Electronic camera with picture selection function and storage medium recording its program

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention relates to an electronic camera that sorts and stores image data in a good shooting state, and a recording medium on which a program is recorded. In particular, the present invention relates to a technique for efficiently performing quality evaluation of image data as a part of an image compression process.

【0002】

[Conventional technology]

In general, in the case of hand-held camera shooting, camera shake often occurs. When such camera shake occurs, the field of view flows and is exposed, so that an overall blurred image is taken. In such a blurred image, the fine details of the entire screen are lost, and the edges that should be clearly captured are lost. Therefore, the image is not very impressive.

【0003】

Conventionally, a camera with a camera shake correction mechanism has been known as a camera for solving such a problem caused by camera shake. FIG. 18 is a diagram showing a camera with a camera shake correction mechanism of this type. In FIG. 18, a photographing lens 92 is attached to the front surface of the camera 91. The blur correction optical system 93 is rotatably arranged in the lens barrel of the photographing lens 92.

【0004】

The blur correction optical system 93 transmits the rotation of the two-axis coreless motors 94 and 95, and vibrates up and down and left and right. On the other hand, on the camera 91 side, a blur amount detection sensor 96 that detects the amount of blur in the left-right direction and a blur amount detection sensor 97 that detects the amount of blur in the vertical direction are arranged. In the camera 91 having such a configuration, the vibration of the camera body is detected by using the blur amount detection sensors 96 and 97. The camera 91 drives the coreless motors 94 and 95 in the direction opposite to the detected vibration to vibrate the optical axis of the blur correction optical system 93. As a result, the vibration of the shooting optical axis is canceled, and a good photograph in which camera shake is corrected can be taken.

【0005】

[Problems to be Solved by the Invention]

By the way, in the conventional example as described above, since the blur correction optical system 93 is arranged, there is a problem that the photographing lens 92 becomes large and heavy. Therefore, an object of the present invention is to provide an electronic camera capable of surely obtaining good image data with less camera shake while solving the above-mentioned problems. In particular, an object of the present invention is to provide an electronic camera that efficiently executes quality evaluation of image data as one of image compression processes.

【0006】

[Means for solving problems]

Hereinafter, means for solving the problem will be described for each claim while associating the reference numerals or step numbers of the embodiments (FIGS. 1 to 17). It should be noted that this association is for reference only, and the configuration of the present invention is not limited thereto.

【0007】

(Claim 1) The invention according to claim 1 includes an imaging means (14) that continuously images a subject, a compression means (17,18) that compresses image data, and an imaging means or an external image. However, the image data is compressed with a compression parameter for quality evaluation via a compression means (S111), and the quality of the image data is evaluated based on the compression code amount (18), and the quality evaluation is performed by the evaluation means. Highly evaluated image data is selected from the image data that has been subjected to the above, and the selected image data is recorded in a state of being compressed to a target compression code amount for image recording via a compression means (18, quality selection means). It is characterized by having 19) and.

【0008】

In the above configuration, the imaging means continuously captures image data of a plurality of frames. The evaluation means performs image compression on each of such image data by using the compression means with compression parameters for quality evaluation (parameters at the time of compression calculation that influence the compression rate). Normally, the image data continuously captured has the same pattern, so that the amount of compression code is almost the same between these images. However, when camera shake, subject blur, out of focus, etc. occur in some image data, the high frequency component of the spatial frequency disappears, and the amount of compression code is reduced accordingly. Therefore, the evaluation means evaluates as better image data as the compression code amount is larger. The quality selection means selects and records good image data according to such an evaluation.

【0009】

By such an operation, in the invention according to claim 1, it is possible to selectively store image data in a good shooting state. In particular, in the invention according to claim 1, the compression means used at the time of recording is diverted to execute the process for quality evaluation. Therefore, it is not necessary to separately provide a processing mechanism dedicated to the quality evaluation, and the device configuration can be simplified.

【0010】

Further, in the invention according to claim 1, when compressing an image at the time of quality evaluation, a dedicated compression parameter independent of that at the time of recording is used. Normally, when the compression rate setting at the time of recording is very high, a large amount of high frequency components of spatial frequency are lost in the compression stage, and the amount of compression code does not change so much between images. On the other hand, if the compression rate setting at the time of recording is very low, minute amplitude signals such as dark current noise and fixed pattern noise are encoded (quantized) as high frequency components, so the amount of compression code is also between images in this case as well. It doesn't change much.

【0011】

From such a phenomenon, when the quality evaluation is performed using the result of image compression at the time of recording, it is assumed that there is no significant difference in the compression code amount and the quality evaluation becomes difficult. However, in the invention according to claim 1, a dedicated compression parameter is used in the quality evaluation. Therefore, apart from recording, it is possible to set a medium compression ratio suitable for quality evaluation. Therefore, it is possible to reliably execute an accurate quality evaluation without being affected by the compression rate setting for recording.

【0012】

(Claim 2) The invention according to claim 2 is the electronic camera according to claim 1, wherein the quality selection means (18, 19) determines the amount of compression code at the time of quality evaluation of the selected image data as an image. Judge whether the target compression code amount for recording is within the permissible range (S121), if it is within the permissible range, record the compressed data at the time of quality evaluation (S122), and if it is not within the permissible range, select it. The image data is recompressed to a target compression code amount for image recording and recorded (S124). As in the above configuration, in the invention according to claim 2, when the code amount of the compressed data at the time of quality evaluation is suitable for recording, the compressed data is recorded. Therefore, it is possible to omit the recompression process for recording, and it is possible to shorten the time required for the entire process.

【0013】

(Claim 3) The invention according to claim 3 is the electronic camera according to claim 1 or 2, wherein the compression means (17, 18) is an image based on the result of the compression process at the time of quality evaluation. It is characterized in that the compression parameter at the time of compression coding to the target compression code amount for recording is determined (S123). Normally, in order to keep the amount of compression code at the time of recording within the target range, it is necessary to correct the compression parameter while performing several trial compressions. However, in the invention according to claim 3, since the compression result at the time of quality evaluation is the trial compression, it is possible to surely reduce the number of trial compressions at the time of recording.

【0014】

(Claim 4) The recording medium according to claim 4 is a program for causing the computer to function as "the compression means, the evaluation means, and the quality selection means according to any one of claims 1 to 3". Is recorded. Recently, there are many cases where an electronic camera is configured as a system consisting of an imaging unit and a computer (including an electronic organizer). Therefore, the electronic cameras according to claims 1 to 3 are immediately configured by realizing the evaluation means and the pass / fail selection means using the recording medium according to claim 4 on a computer having such a system configuration. It becomes possible. In particular, when the evaluation means and the quality selection means according to any one of claims 1 to 3 are realized in a single computer, an image is taken from an electronic camera, a communication medium, a recording medium, a scanner, another program, or the like. It is possible to realize a system that takes in data and executes quality selection of these image data.

【0015】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

【0016】

<First Embodiment> The first embodiment is an embodiment of an electronic camera that evaluates quality and selects images after completing continuous imaging. FIG. 1 is a block diagram showing the configuration of the electronic camera 10. In FIG. 1, a photographing lens 12 is attached to the front surface of the electronic camera 10. The light receiving surface of the image sensor 14 is arranged on the image space side of the photographing lens 12 via the mirror box 13. On the other hand, the finder optical system 13a is arranged in the reflection direction of the mirror box 13.

【0017】

The image output of the image sensor 14 is stored in the image memory 16 via an image processing unit 15 that performs color signal processing, A / D conversion, γ correction, and the like. In addition, the image compression unit 17 and the image display circuit 24 are connected to the data bus of the image memory 16, respectively. The image compression unit 17 is connected to the microprocessor 18. A memory card 20 is detachably connected to the microprocessor 18 via a card interface 19.

【0018】

Further, the microprocessor 18 includes a CCD drive circuit 21 for controlling the image sensor 14, a display unit 22 in the finder for displaying in the finder, a photometric unit 23 for measuring the subject brightness, an image display circuit 24, and a flash. Part 26 and the like are connected. The image output of the image display circuit 24 is supplied to a monitor display unit 25 arranged on the back surface of the housing of the electronic camera 10.

【0019】

Further, in the housing of the electronic camera 10, operation members such as the operation button group 27 and the release button 30 are arranged. The outputs of these operating members are supplied to the microprocessor 18, respectively. Further, a focus detection unit 31 is arranged below the mirror box 13. The focus detection data output from the focus detection unit 31 is supplied to the microprocessor 18. Further, the microprocessor 18 is connected to a lens driving mechanism 32 that drives the focus lens group of the photographing lens 12 back and forth, and an encoder 33 that detects the position of the focus lens group of the photographing lens 12.

【0020】

(Summary Explanation of Main Routine) As one of the shooting modes, the electronic camera 10 is provided with a mode (hereinafter referred to as "good / bad selection mode") in which image data is selected and recorded. FIG. 2 is a diagram showing a main routine executed by the microprocessor 18 when the pass / fail selection mode is set. Hereinafter, the flow of the main routine will be roughly described before explaining the detailed operation.

【0021】

First, the microprocessor 18 executes various settings of the metering mode, the focus detection mode, and the pass / fail selection mode according to the switch operation of the operation button group 27 (step S1). Next, the microprocessor 18 executes the evaluation area setting routine (described later) to set the evaluation area (step S2).

【0022】

The microprocessor 18 repeats these operations until the release button 30 is pressed (NO side of step S3). In this state, when the release button 30 is pressed by the operator (YES side in step S3), the microprocessor 18 drives the image sensor 14 via the CCD drive circuit 21 to perform imaging for one frame (1 frame). Step S4).

【0023】

Next, the microprocessor 18 executes a determination routine (described later) for the imaging stop condition, and determines whether or not to stop continuous imaging (step S5). As a result of such a determination routine, when the stop flag is in the reset state (NO side in step S6), the microprocessor 18 returns to the operation in step S4 and repeats continuous imaging.

【0024】

On the other hand, when the stop flag is set (YES side in step S6), the microprocessor 18 executes the pass / fail evaluation routine (described later) and collectively executes the pass / fail evaluation of the continuously captured image data (step S7). .. Next, the microprocessor 18 determines whether or not at least one of the quality evaluation results exceeds a predetermined allowable value (step S8).

【0025】

Here, if there is no quality evaluation above the permissible value (NO side in step S8), the microprocessor 18 returns to the operation in step S4 and repeats continuous imaging. On the other hand, when there is a quality evaluation equal to or higher than the permissible value (YES side in step S8), the microprocessor 18 determines that good image data has been captured, and proceeds to the next image selection operation.

【0026】

In this image selection operation, the microprocessor 18 first determines the operating conditions of the quality selection mode, and determines whether or not to select the screen of the good image (step S9). Here, when the operating condition for screen selection of the image is selected in advance by the operator (YES side in step S9), the microprocessor 18 executes the display routine (described later) of the selection screen. As a result, the "thumbnail display of continuously captured image data" and the "rank of quality evaluation" are overlapped and displayed on the display unit 25 (step S10).

【0027】

The operator manually selects one of the image data on the display unit 25 as a good image by operating the operation button group 27 (step S11). After accepting the manual selection of the good image, the microprocessor 18 shifts to the operation in step S13. On the other hand, when the operating condition for automatically selecting images is selected in step S9 (NO side of step S9), the microprocessor 18 selects the image data having the first quality evaluation rank as a good image (step S12). ).

【0028】

In this way, the microprocessor 18 compresses and records the good image selected in step S11 or step S12 on the memory card 20 via the card interface 19. The shooting operation in the pass / fail selection mode is completed by the series of operations as described above. Next, the contents of the various subroutines described above will be described individually.

【0029】

(Evaluation area setting routine) Fig. 3 and Fig. 4 show some examples of the evaluation area setting routine. Hereinafter, these examples will be described in order.

【0030】

<< In the case of the setting routine shown in FIG. 3A >> First, the microprocessor 18 sets the metering area as follows according to the type of metering mode set by the photographer (step S20).

【0031】

In the spot metering mode: The area a shown in Fig. 5 (a) is the metering area.

【0032】

In the case of center-weighted metering mode: Areas a and b shown in Fig. 5 (a) are the metering areas (however, the weighting of area a is larger than the weighting of area b).

【0033】

In the case of multi-metering mode: From the areas a to f shown in Fig. 5 (a), the bright area (EV11 or more) and the dark area (EV3 or less) where the gradation reproducibility deteriorates are excluded and remain. The area is a photometric area. Subsequently, the microprocessor 18 determines the evaluation area by diverting the metering area and its evaluation weight set in this way as they are (step S21).

【0034】

<< In the case of the setting routine shown in FIG. 3 (b) >> As shown in FIG. 5 (b), five areas g to k at which focus can be detected are provided in advance in the shooting screen of the electronic camera 10. The photographer can operate the operation buttons group 27 to select a desired focus detection area from the areas g to k. Further, the microprocessor 18 can determine the area where the nearest subject is located based on the focus detection data of each area, and automatically select that area as the focus detection area. Further, a known focus detection technique can be used to change the focus detection area by following the movement of a moving subject. The microprocessor 18 sets the evaluation area at the current position of the focus detection area selected in this way (step S22).

【0035】

<< In the case of the setting routine shown in Fig. 3 (c) >> First, the microprocessor 18 captures the photometric values of several points in the screen from the photometric unit 23. Based on these photometric values, the microprocessor 18 removes the bright area and the dark area from the shooting screen to create an appropriate exposure area (step S23). The microprocessor 18 sets the appropriate exposure area created in this way as the evaluation area (step S24).

【0036】

<< In the case of the setting routine shown in FIG. 3D >> First, the microprocessor 18 determines the focus of several points on the screen via the focus detection unit 31 and creates the focus recognition area (step S25). The microprocessor 18 sets the focusing certification area created in this way as the evaluation area (step S26). It should be noted that such an evaluation area setting can be performed not only when the automatic focus control is executed but also when the focus is manually adjusted or the focus aid is executed.

【0037】

<< In the case of the setting routine shown in FIG. 4 >> First, the microprocessor 18 acquires the switch state of the operation button group 27, and determines whether or not the photographer has performed an operation to lock the focus adjustment (so-called AF lock). (Step S30). Here, if the AF lock is not performed, the microprocessor 18 sets the area selected as the focus detection area as the evaluation area (step S31).

【0038】

On the other hand, when AF lock is performed, the photographer is likely to change the framing in order to change the screen layout. Therefore, the microprocessor 18 cancels the setting of the evaluation area at this point (step S32). Next, the microprocessor 18 acquires the switch state of the operation button group 27, and determines whether or not the photographer has performed an operation to lock the exposure adjustment (so-called AE lock) (step S33).

【0039】

Here, if the AE lock is performed, the photographer is likely to change the framing in order to change the screen layout. Therefore, the microprocessor 18 gives up the range setting of the evaluation area and resets the entire screen to the evaluation area (step S34). On the other hand, when the AE lock is not performed, the microprocessor 18 sets the area selected for the metering area as the evaluation area (steps S35 to S39).

【0040】

(Routine for determining imaging stop condition) Next, the routine for determining the imaging stop condition will be described. FIG. 6 is a diagram showing a determination routine of the imaging stop condition. First, when this determination routine is activated from the main routine, the microprocessor 18 determines the mode setting of the number of imaging frames (step S41).

【0041】

Here, when the fixed number of frames mode is selected by the photographer, the microprocessor 18 determines whether or not the photographer intentionally selects the quality selection mode (step S42). If the quality selection mode is intentionally selected, the photographer does not feel uncomfortable even if the number of images captured is large. Therefore, the microprocessor 18 sets the number of imaging frames to a large number (10 frames in this case) (step S43).

【0042】

On the other hand, when the quality selection mode is automatically selected (for example, when the microprocessor 18 automatically selects the quality selection mode in a state where camera shake is likely to occur such as macro shooting mode), the photographer has a large number of images. Is easy to feel uncomfortable. Therefore, in such a case, the microprocessor 18 sets the number of imaging frames to a small number (here, 3 frames) (step S44). It should be noted that such a fixed number of frames may be set at the time of the setting operation (step S1) before the release.

【0043】

Next, the microprocessor 18 determines whether or not the number of imaging frames has been reached (step S45). Here, when the number of frames to be imaged has not been reached, the microprocessor 18 returns the operation to the main routine while maintaining the stop flag in the reset state. On the other hand, when the number of imaging frames has been reached, the microprocessor 18 determines that the imaging stop condition is satisfied, sets the stop flag (step S46), and returns the operation to the main routine.

【0044】

Further, when the free shooting mode is determined in step S41 above, the microprocessor 18 determines whether or not the press of the release button 30 is released (step S47). Here, if the release button 30 is continuously pressed, the microprocessor 18 returns to the main routine while maintaining the stop flag in the reset state.

【0045】

On the other hand, when the release button 30 is released, it is determined that the imaging stop condition is satisfied, the stop flag is set (step S48), and the operation is returned to the main routine. Further, when the stop determination mode is determined in step S41 above, the microprocessor 18 detects a change in framing based on the difference between frames of the image data (step S49).

【0046】

If no framing change is detected, the microprocessor 18 returns to the main routine. On the other hand, when a change in framing is detected, it is determined that the imaging stop condition is satisfied, the stop flag is set (step S48), and the operation is returned to the main routine. By the series of operations as described above, the determination routine of the imaging stop condition is executed.

【0047】

(Explanation of pass / fail evaluation routine) Next, the pass / fail evaluation routine will be described. FIG. 7 is a diagram showing a pass / fail evaluation routine executed by the microprocessor 18. First, when the pass / fail evaluation routine is started from the main routine, the microprocessor 18 selects one unevaluated image data and extracts the data in the evaluation area from the image data (step S60). The microprocessor 18 processes the data in the evaluation area extracted in this way by using the image compression unit 17 in the following procedure (step S61).

【0048】

(1) The image compression unit 17 divides the data in the evaluation area into 8 × 8 pixel blocks.

【0049】

(2) The image compression unit 17 executes DCT conversion (discrete cosine transform) for each pixel block.

【0050】

(3) The image compression unit 17 weights and adds the DCT transform coefficient for each pixel block. At this time, by weighting the DCT transform coefficient in the zigzag scan order (highest spatial frequency order), an evaluation value indicating how much the high frequency component of the spatial frequency is included can be obtained. The evaluation value for each pixel block thus obtained is further weighted and added to obtain the evaluation value for the entire evaluation area (step S62). At this time, as shown in FIG. 5 (c), the evaluation area is divided into three regions, peripheral portion C1, intermediate portion C2, and central portion C3, and as shown in the following equation, the pixel block closer to the center of the area is evaluated. Set a large weight for.

【0051】

[Evaluation weight of C1] = 0.3 [Evaluation weight of C2] = 0.6 [Evaluation weight of C3] = 1.0 Here, the microprocessor 18 determines whether or not there are a plurality of evaluation areas (step S63).

【0052】

If the evaluation area is singular, the microprocessor 18 determines that the calculation of the evaluation value is completed, terminates the pass / fail evaluation routine, and returns the operation to the main routine. On the other hand, when there are a plurality of evaluation areas, the microprocessor 18 executes (1) weighted addition (2) majority decision calculation (3) maximum value calculation (4) minimum value calculation, etc. for the evaluation value of each evaluation area, and comprehensively performs the evaluation value. Evaluation value is obtained (step S64). Such a series of processes is performed on all the captured image data (step S65).

【0053】

(Selection screen display routine) The selection screen display routine will be described below. FIG. 8 is a flow chart showing a display routine of the selection screen executed by the microprocessor 18. First, when the display routine for image selection is activated from the main routine, the microprocessor 18 determines the mode setting of the screen display (step S71).

【0054】

Here, when the shooting order display mode is selected by the photographer, the microprocessor 18 displays the image data as thumbnails in the shooting order on the display unit 25 via the image display circuit 24 (step S72). On the other hand, when the evaluation order display mode is selected by the photographer, the microprocessor 18 displays the image data as thumbnails in the evaluation order on the display unit 25 via the image display circuit 24 (step S73).

【0055】

The microprocessor 18 overlaps the frame number and the evaluation order with respect to the reduced image displayed as a thumbnail via the image display circuit 24 (step S74). FIG. 9A is a diagram showing a selection screen displayed in such a shooting order display mode. In this selection screen, the image data of the first frame has the highest evaluation order, but the shutter chance is inappropriate and the subject appears quite small. In this case, the photographer can accurately select, for example, the image data of the fourth frame as a good image after considering both the shutter chance and the evaluation order.

【0056】

Further, FIG. 9B is a diagram showing a selection screen displayed in the evaluation order display mode. In this selection screen, the image data having the highest evaluation order has an inappropriate shutter chance, and the subject is in a half-eyed state. In such a case, the photographer can accurately select, for example, the image data having the third evaluation rank as a good image after considering both the shutter chance and the evaluation rank.

【0057】

(Effect of the First Embodiment) According to the operation described above, in the first embodiment, the image data rich in the high-frequency spatial frequency component is selected and recorded from the continuously captured image data. It becomes possible. Therefore, it is possible to selectively obtain image data with less camera shake, subject blur, and out-of-focus.

【0058】

Further, in the first embodiment, since the quality evaluation of the image data is performed within the partial evaluation area, the quality evaluation of the image data can be performed accurately without being affected by the blurring of the background image as much as possible. .. Moreover, since the entire screen is not evaluated as good or bad, the processing time for good or bad evaluation can be shortened. Further, in the first embodiment, since the evaluation weight on the peripheral side of the evaluation area is set lower than the evaluation weight on the central part, the quality evaluation value does not fluctuate significantly due to the image accidentally jumping into the evaluation area. ..

【0059】

Further, in the first embodiment, since it is possible to comprehensively evaluate a plurality of evaluation areas, it is possible to perform an appropriate quality evaluation even in a situation where a plurality of subjects exist on the screen. .. Further, in the first embodiment, it is possible to set an evaluation area excluding the bright area and the dark area in the screen. Therefore, it is possible to avoid an unreasonably low evaluation due to brightness crushing or the like and perform an appropriate quality evaluation focusing on the subject.

【0060】

Further, in the first embodiment, since the in-focus recognition area can be set as the evaluation area, it is possible to appropriately evaluate the quality of the subject image existing at the position in the screen of the in-focus recognition area. Further, in the first embodiment, it is also possible to determine the evaluation area from the light measurement area and the focus detection area. Therefore, it is possible to use both area setting means, and the configuration of the electronic camera 10 related to these area settings can be further simplified.

【0061】

Further, in the first embodiment, when the photographer fixes the focus adjustment or the exposure adjustment, the evaluation area setting can be automatically canceled, so that the reliability of the quality evaluation due to the screen layout change can be quickly avoided. You can also do it. Further, in the first embodiment, it is possible to flexibly change the number of frames for continuous imaging in the determination routine of the imaging stop condition.

【0062】

Further, in the first embodiment, since the continuous imaging can be stopped immediately by detecting the framing change, it is possible to prevent problems such as unnecessarily continuing the continuous imaging after the framing change. Further, in the first embodiment, when the evaluation of the image data does not reach the permissible value, continuous imaging is restarted. Therefore, there is no possibility that the pass / fail selection will be executed in a state where the allowable value is not reached, and the storage of image data at least the allowable value or more is guaranteed.

【0063】

Further, in the first embodiment, the photographer can appropriately select and save image data in a good shooting state via the selection screen. In this case, the photographer can select the image data while referring to the quality evaluation result and also including the subjective evaluation such as the shutter chance. Next, another type of embodiment will be described.

【0064】

<Second Embodiment> The second embodiment is an embodiment of an electronic camera that performs continuous imaging and quality evaluation in parallel. Since the configuration of the second embodiment is the same as that of the first embodiment (FIG. 1) except for the operation program of the microprocessor 18, the description of the configuration is omitted here.

【0065】

(Outline Description of Main Routine) FIG. 10 is a diagram showing a main routine executed by the microprocessor 18 when the pass / fail selection mode is set. Hereinafter, the flow of the main routine will be roughly described before explaining the detailed operation. First, the microprocessor 18 executes various settings such as a metering mode, a focus detection mode, and a pass / fail selection mode according to the switch operation of the operation button group 27 (step S100).

【0066】

Next, the microprocessor 18 executes the evaluation area setting routine as in the first embodiment (step S2). The microprocessor 18 repeatedly executes these setting operations until the release button 30 is pressed (NO side in step S101). In this state, when the release button 30 is pressed by the operator (YES side in step S101), the microprocessor 18 sweeps out unnecessary charges on the image sensor 14 via the CCD drive circuit 21 to expose the first frame. The operation is started (step S102).

【0067】

The microprocessor 18 waits for the elapse of the exposure set time (shutter time), controls the CCD drive circuit 21, and reads out the image data from the image sensor 14 (step S103). From the time when the image data is read out, the image sensor 14 starts the exposure operation of the next frame (step S104).

【0068】

The microprocessor 18 executes an image compression routine (described later) for quality evaluation, and executes quality evaluation of the image data for which imaging has been completed earlier (step S105). Here, if the fluctuation of the pass / fail evaluation result from the previous time is equal to or greater than the threshold value, the microprocessor 18 determines that there is a framing fluctuation (YES side in step S106). In this case, since the pattern itself of the image data changes, the microprocessor 18 determines that it is no longer possible to evaluate the quality under the same conditions, stops continuous imaging, and returns to step S100.

【0069】

On the other hand, if the fluctuation of the pass / fail evaluation result from the previous time is less than the threshold value, the microprocessor 18 determines that there is no framing fluctuation (NO side in step S106). In this case, the microprocessor 18 shifts to step S107 to continue continuous imaging. Incidentally, in such a framing change, it is preferable to set a region where the pattern changes significantly (for example, the peripheral side of the shooting screen) as a framing change detection region. Within such a detection region, the microprocessor 18 can sensitively detect framing changes by monitoring the frame-to-frame difference of image data, fluctuations in the quality evaluation result, and the like.

【0070】

Subsequently, the microprocessor 18 executes an in-finder display routine (described later) and displays the result of the pass / fail evaluation on the in-finder display unit 22 (step S107). Here, the microprocessor 18 determines whether or not the result of the quality evaluation regarding the latest image data is the current maximum evaluation (step S108). If the evaluation is the maximum (YES side in step S108), the microprocessor 18 executes an image overwrite recording routine (described later) and rewrites the recorded image on the memory card 20 with the latest image data (step S109). ).

【0071】

On the other hand, if it is not the maximum evaluation (NO side in step S108), the overwriting image is not executed and the recorded image on the memory card 20 is not updated. Next, the microprocessor 18 determines whether or not the result of the pass / fail evaluation exceeds the maximum point (step S110). Here, if the result of the quality evaluation does not exceed the maximum point (NO side of step S110), it can be determined that there is a high possibility that the quality evaluation of the image data will be further improved. Therefore, the microprocessor 18 returns to the operation in step S103 to continue continuous imaging.

【0072】

On the other hand, when the result of the quality evaluation clearly exceeds the maximum point (YES side in step S109), it can be judged that the possibility that the quality evaluation of the image data is further improved is low. Therefore, the microprocessor 18 returns to the operation in step S100, and temporarily completes the imaging operation in the pass / fail selection mode. The imaging operation in the pass / fail selection mode is completed by the series of operations as described above. Next, the contents of the various subroutines described above will be described individually.

【0073】

(Image compression routine for quality evaluation) FIG. 11 is a diagram showing an image compression routine for quality evaluation. First, when this image compression routine is activated from the main routine, the microprocessor 18 instructs the image compression unit 17 to perform image compression for quality evaluation. The image compression unit 17 extracts the image data in the evaluation area from the latest image data in response to this command. The image compression unit 17 compresses the extracted image data using compression parameters for quality evaluation (here, a scale factor with a compression rate of about 1/10 or a quantization table) (step S111). Next, the microprocessor 18 acquires the compression code amount of the image data compressed in this way and uses it as the evaluation value of the latest image data (step S112). As described above, after obtaining the evaluation value, the microprocessor 18 returns the operation to the main routine.

【0074】

(In-Finder Display Routine) FIG. 12 is a diagram showing an in-finder display routine. First, when the in-finder display routine is activated from the main routine, the microprocessor 18 determines whether or not the current evaluation value of the image data is the maximum evaluation (step S115).

【0075】

If it is the maximum evaluation (YES side in step S115), the microprocessor 18 updates the maximum evaluation value Emax stored in advance in the internal memory area with the value of the current evaluation value E (step S116). ). On the other hand, if it is not the maximum evaluation (NO side of step S115), the microprocessor 18 maintains the value of the maximum evaluation value Emax as it is. Next, the microprocessor 18 displays the maximum evaluation value Emax and the current evaluation value E as bars on the display unit 22 in the finder (step S117). Such an in-finder display routine executes the in-finder display as shown in FIG.

【0076】

(Image Overwriting Recording Routine) FIG. 14 is a diagram showing an image overwriting recording routine. First, when the image overwrite recording routine is activated from the main routine, the microprocessor 18 determines whether or not the evaluation area setting is the entire screen (step S120).

【0077】

If the evaluation area is set as a part of the screen (NO side of step S120), the microprocessor 18 shifts the operation to step S123 in order to perform image compression again for the entire screen. On the other hand, when the evaluation area is set for the entire screen (YES side in step S120), the microprocessor 18 determines whether or not the compression code amount at the time of quality evaluation is within the allowable range of the target compression code amount for recording. Determine (step S121).

【0078】

In step S121, if the compression code amount at the time of quality evaluation is within the permissible range of the target compression code amount for recording, it can be determined that the image compression does not need to be performed again. Therefore, the microprocessor 18 overwrites and records the compressed data at the time of pass / fail evaluation on the memory card 20 as it is (step S122). After completing such overwrite recording, the microprocessor 18 terminates the overwrite recording routine and returns to the main routine.

【0079】

On the other hand, in step S121, if the compression code amount at the time of quality evaluation is out of the permissible range of the target compression code amount for recording, the microprocessor 18 determines that the image compression needs to be performed again, and determines that the image compression needs to be performed again. Move the operation to step S123. In this step S123, the result of image compression at the time of quality evaluation is regarded as the first trial compression result, and a known compression parameter estimation method (for example, Japanese Patent Application Laid-Open No. 4-220879, USP5594554) or the like, or the present application. The compression parameters for recording (here scale factors and quantization tables) are estimated using the method described in Japanese Patent Application No. 10-284531, which is not known at the time of filing the application.

【0080】

Next, the microprocessor 18 recompresses the current image data using the estimated compression parameters (step S124). The microprocessor 18 determines whether or not the compression code amount thus obtained is within the permissible range of the target compression code amount for recording (step S125). Here, if the target compression ratio for recording is out of the allowable range (NO side of step S125), the microprocessor 18 re-estimates the compression parameters (step S126) and operates in step S124. return.

【0081】

On the other hand, if the amount of compression code is within the permissible range of the target compression rate for recording (YES side in step S125), the microprocessor 18 overwrites and records the compressed data compressed here on the memory card 20. (Step S127). After completing the overwrite recording by such a series of operations, the microprocessor 18 returns the operation to the main routine.

【0082】

(Effect of the Second Embodiment) By the operation described above, also in the second embodiment, the image data rich in the high-frequency spatial frequency component is selected and recorded from the continuously captured image data. It becomes possible to do. Therefore, it is possible to reliably obtain image data with less camera shake, subject blur, and out-of-focus.

【0083】

In particular, in the second embodiment, the quality evaluation is performed in parallel with the continuous imaging, so it is possible to determine whether or not to stop the continuous imaging according to the result of the quality evaluation. Therefore, the automatic adjustment of the number of frames becomes accurate, and problems such as the number of frames being insufficient and only low-rated images being captured, or the number of frames being excessive and the shooting time being unnecessarily long are efficiently solved. It can be avoided.

【0084】

Further, in the second embodiment, since the image compression unit 17 is also used to perform image compression for quality evaluation and image compression for recording, it is not necessary to separately provide a processing mechanism for quality evaluation, and the electronic image is used. It is possible to simplify the configuration of the camera 10. Further, in the second embodiment, image compression for quality evaluation is performed using a dedicated compression parameter independent of that for recording. Therefore, regardless of the compression rate setting for recording, it is possible to compress at a medium compression rate suitable for good / bad evaluation, and it is possible to accurately perform good / bad evaluation.

【0085】

Further, in the second embodiment, when the code amount of the compressed data at the time of quality evaluation is suitable for recording, the compressed data is stored as it is. Therefore, it is possible to omit the recompression processing for recording, and it is possible to efficiently shorten the processing time. Further, in the second embodiment, since the compression result at the time of quality evaluation is regarded as trial compression, the number of trial compressions at the time of recording can be efficiently reduced.

【0086】

Further, in the second embodiment, the result of the quality evaluation is displayed in the finder, so that the photographer can refer to the display in the finder and guide the shooting state in the subsequent shooting to a better one. It will be possible. Further, in the second embodiment, the maximum evaluation and the latest evaluation at the present time are displayed on the monitor, so that the photographer can lead the shooting state to a better one with the goal of the maximum evaluation in the subsequent shooting. It becomes. Next, another type of embodiment will be described.

【0087】

<Third Embodiment> The third embodiment is an embodiment in which an image selection system is configured on a computer by using a program in a recording medium. FIG. 15 is a diagram showing a configuration of an image sorting system using the computer 71.

【0088】

In FIG. 15, a microprocessor 72 is provided inside the computer 71. An input device 73 including a keyboard and a mouse, a hard disk 74, a memory 75, an image processing board 76, and an interface board 78 are connected to the microprocessor 72. A monitor 77 is connected to the image output terminal of the image processing board 76. On the other hand, an image input device 79 such as a scanner or an electronic camera is connected to the interface board 78.

【0089】

On the other hand, the CD-ROM drive device 80 is connected to the microprocessor 72. An image processing program and a CD-ROM 81 recording the installation program thereof are inserted into the CD-ROM drive device 80. By the installation program in the CD-ROM81, the microprocessor 72 expands the image processing program in the CD-ROM81 and stores it in the hard disk 74 in an executable state.

【0090】

(Operation of the Third Embodiment) FIG. 16 is a diagram showing a main routine of an image processing program. First, on the computer 71, a plurality of image data are taken in via an image input device 79, another program, or the like, and stored in advance on the hard disk 74. When the image processing program shown in FIG. 16 is executed in such a state, the microprocessor 72 executes the evaluation area setting routine (step S201).

【0091】

If an electronic camera or the like is connected to the computer 71 and information at the time of imaging (information such as light measurement area, focus detection area, presence / absence of AE lock, presence / absence of AF lock, light measurement value, focus recognition area, etc.) can be acquired. For example, the setting routines shown in FIGS. 3 (a) to 3 (d) and FIG. 4 can be executed. On the other hand, in the situation where the information at the time of imaging cannot be acquired, the range setting of the evaluation area by the operator may be accepted via the input device 73 such as a mouse.

【0092】

The evaluation area can also be automatically determined by executing the setting routine shown in FIG. In FIG. 17, first, the microprocessor 72 captures the luminance information of the image data. Based on this brightness information, the microprocessor 72 removes extremely bright and dark areas from the screen and creates a proper exposure area (step S210).

【0093】

Subsequently, the microprocessor 72 sets this proper exposure area as an evaluation area (step S211). After any of these setting routines is executed, the microprocessor 72 executes the quality evaluation routine (FIG. 7) described in the first embodiment, and sequentially executes the quality evaluation of a plurality of image data (the quality evaluation of a plurality of image data). Step S7).

【0094】

Next, the microprocessor 18 determines the setting conditions by the operator and determines whether or not to select a screen of a good image (step S203). Here, when the operating condition for screen selection of the image is selected in advance by the operator (YES side in step S203), the microprocessor 18 is the display routine of the selection screen described in the first embodiment (FIG. 8) is executed, and the "thumbnail display of continuously captured image data" and the "rank of quality evaluation" are displayed on the monitor 77 in an overlapping manner (step S10).

【0095】

The operator manually selects one of the image data on the monitor 77 as a good image by operating the input device 73 (step S205). After accepting the manual selection of the good image, the microprocessor 18 shifts to the operation in step S207. On the other hand, when the setting condition for automatically selecting images is selected in step S203 (NO side of step S203), the microprocessor 18 selects the image data having the first quality evaluation rank as a good image (step S206). ).

【0096】

In this way, the microprocessor 72 stores the good images selected in step S205 or step S206 on the hard disk 74 (step S207). The operation of the image processing program by the computer 71 is completed by the series of operations as described above.

【0097】

(Effects of the Third Embodiment) By the operation described above, it is possible to realize the same effects as those of the first embodiment and the second embodiment on the computer 71 in the third embodiment. Become.

【0098】

<Supplementary Notes to the Embodiment> In each of the above-described embodiments, the spatial frequency component is precisely evaluated by using an orthogonal transform such as a DCT transform, but the present invention is not limited to this. For example, although the accuracy of the quality evaluation is reduced, the high frequency component of the spatial frequency is extracted from the image data in the evaluation area via a known spatial frequency filter or the like, and the quality of the image data is evaluated from the amount of the high frequency component. It is also possible.

【0099】

Further, in each of the above-described embodiments, the case where the quality evaluation is performed based on the spatial frequency component has been described, but the present invention is not limited to this. For example, although the setting range of the evaluation area is unclear, a camera shake detecting means such as an acceleration sensor may be provided in the camera unit, and the camera shake amount detected by the camera shake detecting means may be used as an evaluation item. In addition, the quality of the image data is evaluated using the detail component amount, contrast amount, noise amount, gradation reproducibility, degree of focusing at the time of imaging, degree of proper exposure, color reproducibility, saturation, etc. of the image data as evaluation items. May be done.

【0100】

Further, in each of the above-described embodiments, an example in which the evaluation area is determined in association with the previously set light measurement area or focus detection area has been described, but the present invention is not limited thereto. On the contrary, the evaluation area may be set first, and the light measurement area or the focus detection area may be determined from the evaluation area. Further, in each of the above-described embodiments, the shape and size of the areas are matched between the evaluation area and the other areas, but the present invention is not limited to this. In general, it is not necessary to match the shape and size of the areas because a sufficient effect can be obtained if only the positions in the screen are associated with each other between these areas.

【0101】

Further, in the first and second embodiments described above, the embodiment composed of the electronic camera 10 alone has been described, but the present invention is not limited to this configuration. For example, the electronic camera 10 in these embodiments can be configured as a system including an imaging unit and a computer (including an electronic notebook). In such a case, a program for executing the above-mentioned flow chart may be recorded on a recording medium (memory, CD-ROM, hard disk, etc.), and the program may be executed on the computer side.

【0102】

In the second embodiment described above, continuous imaging is stopped when the evaluation value exceeds the maximum point (step S110), but the present invention is not limited to this. For example, when the evaluation value exceeds a predetermined upper limit value, it may be determined that a sufficiently good image has been captured and continuous imaging may be stopped. Further, the continuous imaging may be stopped when the evaluation value becomes equal to or less than a predetermined lower limit value and it is determined that the continuation of the continuous imaging is meaningless. Further, continuous imaging may be stopped when the number of imaging frames exceeds a predetermined number of frames.

【0103】

Further, the first embodiment has an advantage that continuous imaging can be executed at high speed because image selection is executed after continuous imaging is completed. On the other hand, the second embodiment has an advantage that it is not necessary to temporarily store all the image data because the images are selected and overwritten and saved in parallel with the continuous imaging. Therefore, an operation switching means is provided to determine whether or not there is a margin in the temporary storage capacity, and if there is a margin, high-speed continuous imaging is executed according to the first embodiment. On the other hand, if there is no margin, the second embodiment may be implemented so that the temporary storage capacity is not insufficient. By the operation of such an operation switching means, it is possible to flexibly switch and execute the pass / fail selection mode according to the number of remaining frames of the electronic camera and the like.

【0104】

[Effect of the invention]

(Claim 1) In the invention according to claim 1, image data in a good shooting state can be selectively stored. In particular, in the invention according to claim 1, the quality evaluation is performed by diverting the compression means used at the time of recording. Therefore, it is not necessary to separately provide a dedicated processing means for quality evaluation, and the configuration can be simplified. Further, in the invention according to claim 1, image compression for quality evaluation is performed by using a compression parameter independent of that at the time of recording. Therefore, it is possible to perform moderate image compression suitable for quality evaluation, and it is possible to perform appropriate quality evaluation regardless of the compression rate setting at the time of recording.

【0105】

(Claim 2) In the invention according to claim 2, when the code amount of the compressed data at the time of quality evaluation is suitable for recording, the compressed data is recorded. Therefore, it is possible to omit the recompression process for recording, and it is possible to shorten the time required for the entire process.

【0106】

(Claim 3) In the invention according to claim 3, the number of trial compressions at the time of recording can be surely reduced by regarding the compression result at the time of quality evaluation as one trial compression.

【0107】

(Claim 4) By using the recording medium according to claim 4 on a computer system-configured with an imaging unit or the like, the electronic camera according to claims 1 to 3 can be immediately configured. Become. Further, by using the recording medium according to claim 4 in the computer alone, image data can be taken in from an electronic camera, a communication medium, a recording medium, a scanner, another program, etc., and the quality of these image data can be selected. A computer system to execute can be realized.

[Simple explanation of drawings]

[Figure 1]

It is a block diagram which shows the structure of an electronic camera 10.

[Figure 2]

It is a figure which shows the main routine of 1st Embodiment.

[Fig. 3]

It is a figure which shows the setting routine of an evaluation area.

[Fig. 4]

It is a figure which shows the setting routine of an evaluation area.

[Fig. 5]

It is a figure which shows the arrangement example of each area.

[Fig. 6]

It is a figure which shows the determination routine of the imaging stop condition.

[Fig. 7]

It is a figure which shows the quality evaluation routine.

[Fig. 8]

It is a flow chart which shows the display routine of the selection screen.

[Fig. 9]

It is a figure which shows the display example of the selection screen.

[Fig. 10]

It is a figure which shows the main routine of the 2nd Embodiment.

[Fig. 11]

It is a figure which shows the image compression routine for quality evaluation.

[Fig. 12]

It is a figure which shows the display routine in a finder.

[Fig. 13]

It is a figure which shows the display example in a finder.

[Fig. 14]

It is a figure which shows the overwriting recording routine of an image.

[Fig. 15]

It is a figure which shows the structure of the image selection system using a computer 71.

[Fig. 16]

It is a figure which shows the main routine of an image processing program.

[Fig. 17]

It is a figure which shows the setting routine of an evaluation area.

[Fig. 18]

It is a figure which shows the camera with the conventional camera shake correction mechanism.

[Explanation of symbols]

10 electronic camera 12 Shooting lens 13 Mirror box 14 Image sensor 15 Image processing unit 16 image memory 17 Image compression section 18 microprocessor 19 card interface 20 memory card 21 CCD drive circuit 22 Display in finder 23 Photometer 24 Image display circuit 25 Display 26 Flash 27 Operation buttons 28 Distance measurement mode selection button 29 Shooting mode selection button 30 release button 31 Focus detector 32 Lens drive mechanism 33 encoder 71 Computer 72 MPU 73 Input device 74 hard disk 75 memory 76 Image processing board 77 monitor 78 interface board 79 Image input device 80 CD-ROM drive device 81 CD-ROM