Electronic camera and control program of same

The present invention relates to an electronic camera and a control program thereof.

PROBLEM TO BE SOLVED: To have a dot-like shadow reflected in an image acquired by an electronic camera. The cause is a minute defect on the surface of the optical element or a foreign substance such as a bubble called "bubble" or "butsu" generated inside the optical element. Moreover, the closer the foreign matter is generated to the image sensor, such as an optical filter arranged on the image pickup surface of the image sensor, the more remarkable the effect on the image.

[0003] This foreign matter is a type of foreign matter (hereinafter, referred to as "fixed foreign matter") that is mainly generated during the manufacture of the optical element and does not move with time after the generation. Such fixed foreign matter is one of the factors that deteriorate the performance of the electronic camera. For this reason, it is common to use an optical element for an electronic camera in which the generation of fixed foreign matter is suppressed to a sufficient degree by applying a sufficiently high manufacturing technique.

[0004] However, even if an optical element in which a fixed foreign substance is generated is used, the location where the fixed foreign substance is generated can be found by inspecting the electronic camera before shipping. Therefore, if the manufacturer pre-programs the electronic camera so that the signal affected by the fixed foreign matter is automatically corrected, the influence on the image can be suppressed. Incidentally, such programming is generally performed when the image sensor has defective pixels (Patent Document 1 and the like).

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. 5-68209 [0006] [Problems to be Solved by the Invention] By the way, foreign substances that affect an image include different types of foreign substances from those described above. Exists. It is a foreign substance (hereinafter referred to as "floating foreign substance") that may be newly generated after the electronic camera is shipped and moves with time.

[0007] Floating foreign matter is mainly generated when dust or dirt that has entered from any part of the electronic camera moves and adheres to the surface of the optical element or floats in the imaging optical path. Floating foreign matter is likely to occur, especially when changing lenses in interchangeable lens electronic cameras. However, since the location of such floating foreign matter cannot be predicted before the electronic camera is shipped, the above-mentioned pre-programming is impossible. Therefore, when the user actually acquires an image with an electronic camera and then displays the image on a monitor or the like, the floating foreign matter is discovered for the first time.

[0008] Therefore, the correction for suppressing the influence on the image needs to be performed by the user himself / herself. That is, the user must visually check the image on a monitor or the like, check the location where the floating foreign matter is generated, and specify the floating foreign matter confirmed from the image one by one using computer image software or the like. Must be.

[0009] Incidentally, unlike the fixed foreign matter, it is difficult to prevent the floating foreign matter from being generated. That is, the user frequently cleans the inside of the electronic camera after paying sufficient attention to the handling of the electronic camera to remove dust and dirt that may cause the inside of the electronic camera. However, even if you are careful, some dust will get in. In addition, there are places inside the electronic camera that cannot be cleaned due to the arrangement of the optical elements.

[0010] The present invention has been made in view of such a problem, and an object of the present invention is to provide an electronic camera having a foreign matter self-detection function and a control program thereof.

[0011] [Means for Solving Problems]<u style="single"> Of the present invention</u>An electronic camera includes an image sensor in which an image pickup surface is arranged on the image plane of an optical system.<u style="single">By driving the camera shake correction lens included in the photographing optical system in a direction perpendicular to the optical axis of the photographing optical system, the camera shake correction lens can be driven.</u>Imaging<u style="single">position</u>To<u style="single">Move on the imaging surface</u>An image changing means for changing, and a control means for driving and controlling the image sensor and the image changing means.<u style="single">、</u>The control means drives the image changing means.<u style="single">、</u>Imaging<u style="single">position</u>A plurality of states different from each other are set, and the image sensor is driven in each of these states to acquire a plurality of images, the plurality of images are compared, and the image formation is performed between the images.<u style="single">position</u>It is characterized in that a pattern that does not change with the change of is detected as an image of a foreign substance.

【0012】<u style="single"> In addition, it should be noted.</u>The number of the plurality of images is 2.<u style="single">May</u>。<u style="single"> Also,</u>The number of the plurality of images is 3 or more.<u style="single">May</u>。

【0013】<u style="single"> Also,</u>The plurality of images include at least an image as a reference for the comparison and the image formation on the image.<u style="single">position</u>Includes two images that are offset from each other in the same direction<u style="single">You may.</u><u style="single"> Also,</u>The plurality of images include at least an image as a reference for the comparison and the image formation on the image.<u style="single">position</u>Includes two images that are offset in opposite directions<u style="single">May</u>。

【0014】<u style="single"> Also,</u>Said<u style="single">photograph</u>The diameter of the aperture diaphragm of the optical system can be expanded or contracted, and the control means sets the diameter of the aperture diaphragm to the minimum when acquiring the plurality of images.<u style="single">May</u>。<u style="single"> Also,</u>Immediately after the normal photographing in which the image pickup element is driven in response to an instruction from the outside, the control means performs a series of operations including driving the image changing means and driving the image pickup element, and is acquired by the normal photographing. The detection is performed by comparing the image obtained with the image obtained by the series of operations.<u style="single">May</u>。

【0015】<u style="single"> Also,</u>The control means is said to respond to vibration.<u style="single">Camera shake correction lens</u>The driven camera shake correction mode and the foreign matter detection mode for detecting the foreign matter can be set according to an external instruction, and both the camera shake correction mode and the foreign matter detection mode are set. During the period<u style="single">During the camera shake correction operation by the camera shake correction lens</u>The moving range of the imaging position is limited to be smaller than the moving range of the imaging position during the period when only the camera shake correction mode is set.<u style="single">May</u>。

【0017】<u style="single"> In addition, the present invention</u>The control program of the electronic camera includes an image sensor in which an image pickup surface is arranged on the image plane of the optical system and an image formation of the optical system on the image pickup surface.<u style="single">position</u>Image change means to change<u style="single">、</u>It is a control program of an electronic camera equipped with<u style="single">The image changing portion drives the camera shake correction lens included in the photographing optical system in a direction perpendicular to the optical axis of the photographing optical system, and causes the camera shake correction lens to be driven on the imaging surface.</u>Imaging<u style="single">the position is</u>Set multiple states that are different from each other, and each of these states<u style="single">At</u>The procedure of driving the image sensor to acquire a plurality of images is compared with the plurality of images, and the image formation is performed between the images.<u style="single">position</u>It is characterized by having a procedure of detecting as an image of a foreign substance a pattern in which no change is observed with the change of.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment] First, the first embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, and 4.

FIG. 1 is a configuration diagram of an electronic camera of the present embodiment (and a second embodiment described later). Here, an electronic camera with an interchangeable lens will be described. The electronic camera includes an interchangeable lens unit 20 and an electronic camera body 10. The interchangeable lens unit 20 contains lenses 20a and 20b, a camera shake correction lens 21, an aperture aperture 22, a position sensor 24, an optical system drive mechanism 25, an aperture drive mechanism 26, a vibration sensor 28, an optical system control unit 27, and the like. Be prepared.

[0020] The lenses 20a and 20b and the camera shake correction lens 21 form an image of the luminous flux emitted from the subject on the image pickup surface of the image pickup element 11 in the electronic camera body 10. The optical system drive mechanism 25 includes a gear mechanism, a motor, and the like, and moves the camera shake correction lens 21 (for example, in the direction indicated by the arrow in the figure) so that the imaging position moves on the image pickup surface of the image pickup element 11. ..

[0021] The position sensor 24 detects the position of the camera shake correction lens 21. The diaphragm drive mechanism 26 includes a gear mechanism, a motor, and the like, and expands or contracts the diameter of the aperture diaphragm 22. The vibration sensor 28 includes an acceleration sensor and the like, and detects the vibration of the interchangeable lens unit 20.

[0022] The optical system control unit 27 is composed of a microprocessor or the like, and drives and controls each unit in the interchangeable lens unit 20 under the instruction of the main control unit 12 in the electronic camera body 10 to perform camera shake correction and the like. Camera shake correction is realized as follows. That is, when the main control unit 12 instructs to start the camera shake correction, the optical system control unit 27 is for camera shake correction necessary for canceling the shake vector (direction and amount) indicated by the output of the vibration sensor 28. Calculate the amount of movement of the lens 21. Then, an instruction is given to the optical system drive mechanism 25 while referring to the output of the position sensor 24 so as to move the camera shake correction lens 21 by the amount of the movement. As a result, camera shake correction is realized, and a certain imaging range is projected on the imaging surface of the image sensor 11 without blurring.

On the other hand, in the electronic camera body 10, an image sensor 11, an AD conversion unit 14, a signal processing unit 15, a buffer memory 16, a display unit (LCD, etc.) 13, a release button 18a, an operation button 18b, and an external storage unit are included. (Portable memory and its reader, etc.) 19, main control unit 12, etc. are provided.

[0024] The image pickup device 11 captures an image of a subject formed on the image pickup surface thereof. A cover glass 11a, an optical filter 11b, and the like are arranged in order from the position closest to the image sensor 11 on the front surface of the image sensor 11. Dust that has entered the vicinity of the cover glass 11a and the optical filter 11b is the main cause of floating foreign matter, and bubbles generated during the manufacture of the cover glass 11a and the optical filter 11b are the main causes of the fixed foreign matter.

The AD conversion unit 14 and the signal processing unit 15 process the signal output from the image sensor 11. The signal is stored in the buffer memory 16 and recorded in the external storage unit 19 as needed. The display unit 13 displays an image based on the image data output from the image sensor 11, information necessary for the user of the electronic camera to operate the release button 18a and the operation button 18b, and the like.

[0026] The main control unit 12 is composed of a microprocessor or the like, and in response to the operation of the release button 18a or the operation button 18b by the user, each part in the electronic camera body 10 is driven and controlled to perform imaging, or the interchangeable lens 20 The camera shake correction described above is started / ended by controlling the optical system control unit 27 in the lens. Imaging is realized as follows.

That is, when the user gives an image pickup instruction (when the release button 18a is fully pressed), the main control unit 12 drives the image pickup element 11. The main control unit 12 stores the signal output from the image sensor 11 at this time in the buffer memory 16 via the AD conversion unit 14 and the signal processing unit 15. Next, the characteristic operation of the electronic camera of the present embodiment will be described in detail.

[0028] The display unit 13 displays a setting screen as shown in FIGS. 2A and 2B in response to the operation of the release button 18a and the operation button 18b. When the setting screen shown in FIG. 2A is displayed, the user can set / cancel the "foreign matter detection mode" and the "camera shake correction mode" for the electronic camera body 10, respectively. The setting / cancellation by this user is performed via the release button 18a or the operation button 18b.

[0029] When the main control unit 12 recognizes the content set by the user based on the operation amount of the release button 18a and the operation button 18b, the main control unit 12 stores the content in a predetermined area of the memory in the main control unit 12 and stores the content. To do. When the user sets the "foreign matter detection mode", the setting screen shown in FIG. 2B is displayed on the display unit 13.

When the setting screen shown in FIG. 2B is displayed, the user sets the image saving method to either "record the image before correction" or "record the image after correction". It can be set to one. The setting by this user is performed via the release button 18a and the operation button 18b. When the main control unit 12 recognizes the content set by the user based on the operation amount of the release button 18a and the operation button 18b, the main control unit 12 stores and stores the content in a predetermined area of the memory in the main control unit 12.

FIG. 3 is an operation flowchart of the main control unit 12 of the present embodiment. This operation flowchart is started every time the release button 18a is pressed halfway. When this operation flowchart is started, the main control unit 12 refers to the memory and determines whether or not the camera shake correction mode is set (step S1).

If the camera shake correction mode is set, an instruction is given to the optical system control unit 27 to start the camera shake correction (step S2). Further, the main control unit 12 determines whether or not the foreign matter detection mode is set by referring to the memory (step S3), and if it is set (step S3YES), proceeds to step S4 and detects foreign matter together with normal imaging. If it is not set (step S3NO), the process proceeds to step S12 and only normal imaging is performed.

[0033] In step S4, it is determined whether or not the release button 18a is fully pressed, and imaging is performed at the time when the release button 18a is fully pressed (step S4YES) (step S5). If the camera shake correction is in progress, the main control unit 12 instructs the optical system control unit 27 to end the camera shake correction when the imaging is completed. Hereinafter, the image acquired when the release button 18a is fully pressed in this way is referred to as a save image (see FIG. 4 (a1)).

[0034] When the image for storage is acquired, the main control unit 12 immediately gives an instruction to the optical system control unit 27 to move the camera shake correction lens 21 (step S6). The optical system control unit 27 gives an instruction to the optical system drive mechanism 25 to move the camera shake correction lens 21 while referring to the output of the position sensor 24. At this time, as shown in FIG. 4A2, the imaging position on the imaging surface of the image pickup device 11 (the position of the image 4a of the subject formed on the imaging surface) moves by a predetermined amount. Hereinafter, the amount of movement of the imaging position is referred to as Δ (note that the amount of movement of the imaging position is a predetermined amount in the horizontal direction in FIG. 4, but the moving direction of the imaging position may be the vertical direction).

Regarding the amount of movement of the camera shake correction lens 21 required to move the imaging position by a predetermined amount, the main control unit 12 determines the aperture value of the aperture diaphragm 22 and the focal length of the interchangeable lens unit 20. , Calculated based on the reference shooting information consisting of the shooting distance and the like. When the state in which the imaging position is moved by Δ is secured in this way, the main control unit 12 immediately captures an image (step S7).

[0036] Hereinafter, this image automatically acquired following the image for storage is referred to as a "comparison image" (see FIG. 4 (a2)). When acquiring these storage images and comparison images (steps S5 and S7) during the period in which the foreign matter detection mode is set (step S3YES side), the main control unit 12 sets the diameter of the aperture stop 22. May be instructed to the optical system control unit 27 to minimize. The optical system control unit 27 sets such a diameter via the aperture drive mechanism 26.

[0037] The reason why the diameter of the aperture diaphragm is minimized is to increase the depth of field of the electronic camera so that foreign matter can be clearly reflected, thereby improving the detection accuracy of foreign matter. Next, the main control unit 12 compares the data of the storage image with the data of the comparison image, detects a foreign substance, and calculates correction data according to the foreign substance (step S8).

As shown in FIGS. 4 (a1) and 4 (a2), the image 4a of the subject is deviated by Δ between the storage image and the comparison image. On the other hand, in the image for storage and the image for comparison, the image 4b of the foreign matter is not affected at all. The main control unit 12 in step S8 performs conversion on one of the images (hereinafter referred to as a comparison image) in order to facilitate comparison between the storage image and the comparison image (FIG. 4 (FIG. 4). b1), (b2)).

[0039] In this conversion, the entire comparison image is converted so that the position of the image 4a of the subject is the same as the position of the image 4a of the subject in the preservation image. However, between the storage image and the comparison image, the image 4a of the subject is not only shifted (shifted) by Δ from each other, but also slightly distorted. Therefore, the above-mentioned conversion also includes an operation for correcting the distortion.

The calculation content for this conversion may be determined according to the movement pattern of the camera shake correction lens 21 in step S6, but is based on the storage image and the comparison image as follows. It may be decided. That is, image recognition processing is performed based on the storage image and the comparison image to recognize the common pattern (= subject image) 4a in each image, and between the respective common patterns (= subject image) 4a. The calculation content is determined based on the shift amount and the distortion amount of.

Then, when the difference between the data of the comparison image after this conversion and the data of the image for storage is taken, as shown in FIG. 4 (c), the portion showing the common pattern (= image of the subject) 4a. Is 0, and the portion showing the image 4b of the foreign substance is not 0, but is a value corresponding to the density of the image 4b of the foreign substance. Therefore, the main control unit 12 takes the difference between the data of the comparison image after conversion and the data of the image for storage, and there is no image of foreign matter in the region where it becomes 0, and it becomes a value other than 0. It is judged that an image of a foreign substance exists in the area.

[0042] Then, the main control unit 12 has a pixel address (size and position of the foreign matter image) corresponding to the foreign matter image 4b and a pixel value corresponding to the foreign matter image 4b in the data of the image for storage. (Density of image of foreign matter) is recognized. Further, based on the recognized pixel address and pixel value, the main control unit 12 determines the correction content (hereinafter referred to as "correction data") to be applied to the data of the image for storage in order to suppress the influence of foreign matter. To do.

[0043] Here, this correction should be performed by an interpolation operation with reference to the pixel values around the image 4b of the foreign matter. Therefore, the correction data is a parameter that determines the content of this interpolation operation. For example, the correction data has three parameters: a pixel address corresponding to the center of the foreign object image 4b, a pixel address of a peripheral pixel to be referenced, and each coefficient to be multiplied by the pixel value of the referenced peripheral pixel. ..

[0044] When the correction data is determined in this way, the main control unit 12 refers to the memory, and as an image saving method, "records the corrected image" and "records the image before correction". Determine which is set (step S9).

If it is the former (step S9YES), the main control unit 12 proceeds to step S10, corrects the data of the image for storage according to the correction data (interpolation calculation), and obtains the corrected data. , Write to external storage unit 19, etc. In the latter case (step S9NO), the main control unit 12 proceeds to step S11 and writes the data of the image for storage and the correction data to the external storage unit 19 or the like in association with each other without performing the correction.

When the foreign matter detection mode is not set (step S3NO side), only the image for saving is acquired (step S13) in response to the operation of fully pressing the release button 18a (step S12YES). Yes, steps S6 to S11 (detection of foreign matter) described above are not executed at all. As described above, in the electronic camera of the present embodiment, two images (preservation image and comparison image) obtained while changing the imaging position on the imaging surface were compared, and only displacement was not observed between the images. The picture is considered a foreign object. Therefore, both fixed foreign matter that does not move and floating foreign matter that may move with time are reliably detected.

Moreover, in the electronic camera of the present embodiment, since the comparison image is automatically acquired after the imaging in step S5, the user can concentrate on the imaging without fearing the generation of foreign matter. Moreover, in the electronic camera of the present embodiment, the mechanisms (position sensor 24, optical system drive mechanism 25, optical system control unit 27, vibration sensor 28) mounted for camera shake correction are effectively used for detecting foreign matter. ing.

[0048] Further, the user can set / cancel the foreign matter detection mode for the electronic camera, and for the electronic camera, the image saving method is "record the image before correction" and "image after correction". Can be set to either "Record". If "Record the image before correction" is set, correction data according to the type of foreign matter (size, position, and density of the image of the foreign matter) is acquired together with the data of the image for storage. That is, the user can obtain the information necessary for obtaining an image in which the influence of foreign matter is suppressed.

On the other hand, if "Record the corrected image" is set, appropriate correction according to the type of foreign matter (size, position, and density of the image of the foreign matter) can be performed on the data of the image for storage. Is automatically applied to. That is, the user can obtain image information in which the influence of foreign matter is suppressed. That is, the electronic camera of the present embodiment can flexibly respond to various requests of the user.

[0050] To show the correspondence between the present embodiment and the claims, the image sensor 11 corresponds to the image sensor, and the optical system drive mechanism 25, the position sensor 24, and the optical system control unit 27 serve as image changing means. Correspondingly, the main control unit 12 and the optical system control unit 27 correspond to the control means. Further, in the present embodiment, a method focusing on the contents of the comparison image and the storage image (subject image 4a), that is, one of the comparison image and the storage image has the position of the subject image 4a as the other. The method of converting the two data so that they are the same and then taking the difference between the two data was adopted, but the following method can also be adopted.

[0051] In this method, the storage image and the comparison image are output as they are (output from the image sensor 11) without paying attention to the contents of the comparison image and the storage image (such as the image 4a of the subject). It is a method of superimposing on the data state) and taking the difference between the two data. In this method, it may be determined that the image of the foreign matter does not exist in the region where the difference is a value other than "0", and the image of the foreign matter exists in the region where the difference becomes "0".

[0052] In short, any method may be adopted as long as it is possible to distinguish between the changed portion and the unchanged portion between the comparison image and the storage image.

[Second Embodiment] Next, the second embodiment of the present invention will be described with reference to FIGS. 1, 5, and 6.

[0053] Hereinafter, only the differences from the first embodiment will be described. The electronic camera of the present embodiment is equivalent to the electronic camera of the first embodiment including the main control unit 42 instead of the main control unit 12. FIG. 5 is an operation flowchart of the main control unit 42 of the present embodiment. Of the steps shown in FIG. 5, the same steps as those shown in FIG. 3 are designated by the same reference numerals, and the description thereof will be omitted.

[0054] Further, the operation flowchart shown in FIG. 5 is started every time the release button 18a is half-pressed, similarly to the operation flowchart shown in FIG. First, as shown in steps S7 and S22 of FIG. 5, in the present embodiment, the number of acquired comparative images is two or more. The reason for increasing the number of acquisitions in this way is to improve the accuracy of foreign matter detection.

That is, when the release button 18a is fully pressed (step S4YES) when the foreign matter detection mode is set (step S3YES), the main control unit 42 moves the camera shake correction lens 21 (step S6). ') And acquisition of the comparison image (step S7) are performed a plurality of times. The amount of movement of the camera shake correction lens 21 (that is, the amount of movement of the imaging position) in step S6', which is performed a plurality of times, is different each time.

[0056] For example, when the comparison image is acquired twice, when the moving amount of the imaging position in the first step S6'is + Δ, the moving amount of the imaging position in the second step S6' Is preferably set to -Δ, which is the opposite (here, the amount of movement of the imaging position is expressed with reference to the imaging position at the time of acquisition of the image for storage (step S5)).

[0057] Hereinafter, a case where the number of acquired images for comparison is 2 (that is, the number of acquired images when the image for storage is included is 3) will be described. In this case, the simplest and most reliable detection of foreign matter is possible.

Here, the image for storage is shown in FIG. 6 (a1), and the image shown in FIG. 6 (a2) is for comparison obtained when the amount of movement of the imaging position is + Δ. An image (hereinafter referred to as "first comparison image"), and shown in FIG. 6 (a3) is a comparison image acquired when the amount of movement of the imaging position is -Δ (hereinafter, referred to as "first comparison image"). It is called "second comparison image").

As shown in FIGS. 6 (a1) and 6 (a2), the image 4a of the subject is deviated by + Δ between the storage image and the first comparison image. However, since the images 4b and 4b'of the foreign matter do not move due to the movement of the camera shake correction lens 21, they exist at the same position in the storage image and the first comparison image. Here, the foreign matter image 4b located near the center of the storage image is located in the area where the subject image 4a exists on the first comparison image, but is located in the peripheral portion of the storage image. The foreign matter image 4b'located in is located in the region 4c outside the area where the subject image 4a exists on the first comparison image (for this reason, the preservation image and the first comparison). Foreign matter 4b'cannot be detected only by comparing it with the image for use.)

Further, as shown in FIGS. 6 (a1) and 6 (a3), the common pattern 4a is deviated by Δ between the storage image and the second comparison image. However, since the images 4b and 4b'of the foreign matter do not move due to the movement of the camera shake correction lens 21, they exist at the same position in the storage image and the second comparison image. Here, both the images 4b and 4b'of the foreign matter are located in the area where the image 4a of the subject exists on the second comparative image.

[0061] The main control unit 42 in step S8'combines the first comparison image and the second comparison image (FIG. 6 (b2)). On the composite image for comparison (Fig. 6 (b2)), the image 4b of the foreign matter located near the center of the image for preservation appears at positions deviated by + Δ and -Δ from that position, respectively. On the other hand, the image 4b'of the foreign matter located in the peripheral portion of the image for storage does not appear at a position deviated by + Δ from that position, but appears only at a position deviated by -Δ.

[0062] Then, the main control unit 42 takes a difference between the data of the storage image (FIG. 6 (b1)) and the data of the composite image (FIG. 6 (b2)) after synthesis (FIG. 6 (c)). )). At this time, the difference in the region "0", the difference in the region "+ Δ", and the difference in the region "-Δ" with respect to the position of the image 4b of the foreign matter on the storage image are 0, respectively. It becomes a value other than. In addition, the difference in the area of position "0" and the difference in the area of position "-Δ" with respect to the position of the image 4b'of the foreign matter on the image for storage are values other than 0, respectively (Fig. 6 (c)). )reference).

[0063] The main control unit 42 determines that the image of the foreign matter does not exist in the region where the difference becomes 0, and the image of the foreign matter exists in the region where the difference becomes a value other than 0. After that, the process of determining the correction data and the process of saving the image are performed in the same manner as each process in the first embodiment (see steps S8 to S11 in FIG. 3). By the way, the presence or absence of foreign matter in the first embodiment described above can be determined only in the area where the pattern common to both the storage image and the comparison image exists. That is, the evaluation target area 5a in the first embodiment was a part of the image for preservation as shown by diagonal lines in FIGS. 4 (b1) and 4 (b2).

[0064] Therefore, in the first embodiment (described above), the foreign matter can be detected in a short time because the number of acquired comparative images is small, but the image of the foreign matter is temporarily reflected in the corner of the imaging range. If so, it may not be detected. However, in the present embodiment, by synthesizing two comparison images whose images are shifted in opposite directions, the pattern common to both the storage image and the comparison image is enlarged (Fig. 6 (b1)). ), (B2)). That is, the evaluation target area 5a in the present embodiment is the entire image for storage as shown by diagonal lines in FIGS. 6 (b1) and 6 (b2).

Therefore, according to the present embodiment, even if an image of a foreign object is reflected in the corner of the imaging range, it can be reliably detected. That is, according to the present embodiment, the detection accuracy of foreign matter is increased. Since the electronic camera of the present embodiment is provided with a camera shake correction function, when the camera shake correction mode is set, the above-mentioned image for saving is also acquired (step S5). The camera shake correction function works.

Therefore, the position of the camera shake correction lens 21 is not always at the reference position when the image for storage is acquired (step S5) (reference position: the optical axis of the camera shake correction lens 21 is set. Positions that coincide with the optical axes of the other lenses 20a and 20b). Needless to say, the movable range of the camera shake correction lens 21 is predetermined by the size of the housing of the interchangeable lens unit 20 and the like.

[0067] If the amount of camera shake at the time of acquiring the image for storage (step S5) becomes extremely large, the position of the camera shake correction lens 21 becomes the upper limit of the movable range, and the result in step S6. It may be impossible to move the image position. In order to avoid such a situation, it is desirable that the electronic camera of the present embodiment is configured as follows.

That is, when both the camera shake correction mode and the foreign matter detection mode are set in the electronic camera (YES side in step S1 and YES side in step S3), camera shake correction during camera shake correction is performed. The main control unit 42 instructs the optical system control unit 27 to limit the movement range of the lens 21 to a predetermined range smaller than the movable range (step S21). Upon receiving this instruction, the optical system control unit 27 calculates even if the movement amount of the camera shake correction lens 21 calculated for performing camera shake correction is large, if the movement amount exceeds the movement range. Regardless of the amount of movement, the camera shake correction lens 21 is moved only within the movement range.

[0069] As a result, when the amount of camera shake is extremely large, the effect of camera shake correction becomes small, but the accuracy of detecting foreign matter is kept high.

[Supplement to the 1st Embodiment or the 2nd Embodiment] Conventionally, the generation of fixed foreign matter in an electronic camera has been prevented by improving the manufacturing accuracy of each optical element in the electronic camera.

However, since the electronic camera of each of the above embodiments can self-detect foreign matter, a good image (or information for obtaining a good image) can be obtained even if the manufacturing accuracy is not improved. be able to. In addition, conventionally, fixed foreign matter generated in an electronic camera has been detected by inspection before shipment of the electronic camera.

However, since the electronic camera of each of the above embodiments can self-detect a foreign substance, even if the inspection step is omitted, a good image (or information for obtaining a good image) can be obtained. Obtainable. Therefore, according to each of the above embodiments, it is possible to suppress the manufacturing cost of the electronic camera while ensuring the performance of the electronic camera.

In each of the above embodiments, the amount of movement of the imaging position in steps S6 and S6'is set to a predetermined value, but the amount of movement of the camera shake correction lens 21 is set to a predetermined value. May be good. In this case, instead of obtaining the movement amount of the camera shake correction lens 21 from the movement amount of the imaging position in steps S6 and S6', the movement amount of the camera shake correction lens 21 is obtained in steps S8 and S8'. The amount of movement of the imaging position is obtained.

[0073] Further, a known image recognition method may be applied to the processing in steps S8 and S8'of each of the above embodiments to surely improve the detection accuracy of foreign matter. Incidentally, as a known image recognition method, for example, there is a method of recognizing a pattern depending on the presence or absence of periodicity of the image. This is a so-called "method using an autocorrelation function" which is generally used when analyzing a random phenomenon having no periodicity or reproducibility.

Further, in each of the above embodiments, the electronic camera having the camera shake correction function has been described, but as long as the means for moving the imaging position is provided even if the camera shake correction function is not provided, the above is described. It is possible to detect foreign matter. As means for moving the image, in addition to the mechanism for moving the camera shake correction lens 21 as in each of the above embodiments, a mechanism for shifting the optical axis of the light flux incident on the image sensor 11 and the image sensor 11 are used. A moving mechanism or the like may be applied. However, in the latter case, the only foreign matter that can be detected is the foreign matter adhering to the image sensor 11.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS. 7 and 8. Here, only the difference from the first embodiment will be described. FIG. 7 is a configuration diagram of the electronic camera of the present embodiment. In FIG. 7, the same elements as those shown in FIG. 1 are designated by the same reference numerals.

[0076] In the interchangeable lens unit 30 of the electronic camera of the present embodiment, the lenses 30a and 30b, the focus adjustment lens 31, the aperture diaphragm 22, the position sensor 34, the optical system drive mechanism 35, the aperture drive mechanism 26, and the optical system A control unit 67 and the like are provided. When the focus adjustment lens 31 moves in the optical axis direction (direction indicated by the arrow in the figure), the imaging position of the subject by the interchangeable lens unit 30 moves in the optical axis direction.

The position sensor 34 detects the position of the focus adjustment lens 31, and the optical system drive mechanism 35 moves the focus adjustment lens 31 in the optical axis direction (direction indicated by an arrow in the drawing) to control the optical system. The unit 67 drives and controls each unit in the interchangeable lens unit 30. Like the electronic camera of the first embodiment, the electronic camera of the present embodiment equipped with such an interchangeable lens unit 30 can be set and released in the "foreign matter detection mode" by the user (see FIG. 2).

[0078] The electronic camera of the present embodiment set to the foreign matter detection mode operates as follows. When the release button 18a is pressed halfway, the main control unit 62 adjusts the focus to a position (focusing position) where the focusing state (the state in which the imaging position is on the image pickup surface of the image sensor 11) is achieved. An instruction is given to the optical system control unit 67 to move the lens 31. The amount of movement of the focus adjustment lens 31 required to achieve the in-focus state is determined by the main control unit 62 and / / based on the amount of defocus measured by the attached focus detection device in the electronic camera body 10. Alternatively, the optical system control unit 67 calculates.

[0079] The optical system control unit 67 gives an instruction to the optical system drive mechanism 35 to move the focus adjusting lens 31 by the amount of movement while referring to the output of the position sensor 34. When the in-focus state is achieved in this way, as shown in FIG. 8 (1), the image 4a of the subject formed on the image pickup surface of the image pickup device 11 is in a state of high contrast without blurring.

After that, when the release button 18a is fully pressed, an image is taken and an image for storage is acquired. When the image for storage is acquired, the main control unit 62 immediately instructs the optical system control unit 67 to move the focus adjustment lens 31 from the in-focus position. The optical system control unit 67 gives an instruction to the optical system drive mechanism 35 to move the focus adjustment lens 31 while referring to the output of the position sensor 34.

When the focus adjusting lens 31 moves from the in-focus position in this way, the image 4a of the subject formed on the image pickup surface of the image pickup device 11 is blurred as shown in FIG. 8 (2). That is, the contrast of the subject image 4a is reduced. When the blurred state of the image 4a of the subject is secured, the main control unit 62 immediately takes an image and acquires a comparison image.

[0082] When acquiring these storage images and comparison images, the main control unit 62 may give an instruction to the optical system control unit 67 to minimize the diameter of the aperture diaphragm 22. ..

Next, the main control unit 62 compares the data of the storage image with the data of the comparison image, detects a foreign substance, and calculates correction data according to the foreign substance. As shown in FIGS. 8 (1) and 8 (2), the latter is more blurred between the subject image 4a in the preservation image and the subject image 4a in the comparison image, and the contrast changes. However, the degree of blurring and the contrast are the same between the image of foreign matter 4b in the preservation image and the image of foreign matter 4b in the comparison image.

[0084] Therefore, the main control unit 62 compares the contrast of these storage images with the contrast of the comparison image, detects a region where the contrast does not change between the two images, and detects a foreign matter in that region. Judge that the image exists. After that, the process of determining the correction data and the process of saving the image are performed in the same manner as each process in the first embodiment (see steps S8 to S11 in FIG. 3).

[0085] As described above, in the present embodiment, the method of changing the imaging state is different from that in the first embodiment (in the present embodiment, the imaging position on the optical axis is changed, whereas the first embodiment is changed. In the embodiment, the imaging position on the imaging surface is changed), but both the fixed foreign matter and the floating foreign matter are reliably detected as in the first embodiment.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described with reference to FIGS. 9 and 10.

[0086] Here, only the differences from the first embodiment will be described. FIG. 9 is a configuration diagram of the lens of the electronic camera of the present embodiment. In FIG. 9, the same elements as those shown in FIG. 1 are designated by the same reference numerals. The interchangeable lens unit 40 of the electronic camera of the present embodiment includes lenses 40a, 40b, 40c, an aperture diaphragm 22, a position sensor 44, an optical system drive mechanism 45, an optical system control unit 87, and the like.

[0087] When the lenses 40a, 40b, and 40c move in the optical axis direction, the imaging magnification of the interchangeable lens unit 40 changes. The position sensor 44 detects each position (zoom position) of the lenses 40a, 40b, and 40c, and the optical system drive mechanism 45 moves the lenses 40a, 40b, and 40c in the optical axis direction (the direction indicated by the arrow in the figure). , The optical system control unit 87 drives and controls each unit in the interchangeable lens unit 40.

[0088] The electronic camera of the present embodiment equipped with such an interchangeable lens unit 40 can be set and canceled by the user in the "foreign matter detection mode" as in the electronic camera of the first embodiment (FIG. 2). reference). The electronic camera of the present embodiment set to the foreign matter detection mode operates as follows. When the release button 18a is fully pressed, an image is taken and an image for storage is acquired.

[0089] When the image for storage is acquired, the main control unit 82 immediately gives an instruction to the optical system control unit 87 to change the zoom position of the interchangeable lens unit 40. The optical system control unit 87 gives an instruction to the optical system drive mechanism 45 to move the lenses 40a, 40b, and 40c while referring to the output of the position sensor 44. When the zoom position changes in this way, as shown in FIGS. 10 (1) and 10 (2), the size of the subject image 4a formed on the image pickup surface of the image sensor 11 changes, and each of the subject images 4a changes. The distance from the center of the position varies.

[0090] When the changed state of the size of the image 4a of the subject is secured, the main control unit 82 immediately takes an image and acquires a comparison image. When acquiring these storage images and comparison images, the main control unit 82 may give an instruction to the optical system control unit 87 to minimize the diameter of the aperture diaphragm 22.

Next, the main control unit 82 compares the data of the storage image with the data of the comparison image, detects a foreign substance, and calculates correction data according to the foreign substance. As shown in FIGS. 10 (1) and 10 (2), the size (distance from the center of each position of the image 4a) is between the image 4a of the subject in the preservation image and the image 4a of the subject in the comparison image. However, the size (distance from the center of each position of the image 4b) is the same between the image 4b of the foreign body in the preservation image and the image 4b of the foreign body in the comparison image.

Therefore, the main control unit 82 compares these storage images with the comparison image, detects a region (pattern) in which the size does not change between the two images, and an image of a foreign substance in that region. Judge that exists. After that, the process of determining the correction data and the process of saving the image are performed in the same manner as each process in the first embodiment (see steps S8 to S11 in FIG. 3).

[0093] As described above, in the present embodiment, the method of changing the imaging state is different from that in the first embodiment (in the present embodiment, the imaging magnification is changed, whereas in the first embodiment, the imaging magnification is changed. The imaging position on the imaging surface is changed.) However, both the fixed foreign matter and the floating foreign matter are reliably detected as in the first embodiment.

[Supplement to the 3rd Embodiment or the 4th Embodiment] The electronic cameras of the 3rd embodiment and the 4th embodiment described above have the same number of acquired images for comparison as the electronic cameras of the 1st embodiment. Although it is 1, the number of acquired images for comparison may be increased to 2 or more to improve the accuracy of foreign matter detection as in the electronic camera of the second embodiment.

[0094] The direction of deviation of the imaging state of the two comparative images with respect to the storage image may be the "opposite direction" as in the second embodiment, but the "same direction". It may be. Further, also for the electronic cameras of the third embodiment and the fourth embodiment, the detection accuracy of foreign matter may be surely improved by applying a known image recognition method.

[Others] The electronic camera of each of the above embodiments is configured to calculate correction data according to the type of foreign matter (size, position, and density of the image of the foreign matter). The configuration may be changed so that only the presence / absence is detected and the user is notified of the presence / absence. Further, in each of the above-described embodiments, each operation of the electronic camera is realized by processing by the main control units 12, 42, 62, and 82 provided in advance in the electronic camera. Such a main control unit 12 , 42, 62, 82 may prepare a recording medium on which a program corresponding to a part or all of the processing is recorded, and mount the recording medium on an electronic camera as needed.

[0096] Further, the user of the electronic camera may download such a program from a predetermined homepage via a computer and the Internet. For example, the download is executed by selecting the electronic camera in use from the products displayed on the screen while accessing the predetermined homepage from the computer.

[0097] Further, the following dial-up connection can be applied as a connection form between the computer and the Internet. That is, the computer is connected to the telephone line via a modem or terminal adapter, and is connected to the modem or terminal adapter of the provider, which is an Internet connection service company, via this telephone line.

[0098] The modem or terminal adapter of the provider is connected to the server, and the server is connected 24 hours a day via a router for setting a relay route to the Internet. The user makes a phone call from the computer when needed and connects to the Internet (home page) via the provider's server.

[0099] The connection form between the computer and the Internet is not limited to such a dial-up connection, and may be a form in which the computer is always connected to the provider using a dedicated line. When a known continuous shooting function is added to any of the electronic cameras of the above-described embodiments, the data of a plurality of images acquired by the continuous shooting may occupy the memory. The control units 12, 42, 62, and 82 may be restricted so that the foreign matter detection mode can be set only when the memory storage area has a margin. As a result, the memory is effectively used.

[0100] The electronic camera of each of the above embodiments is configured such that once the user sets the foreign matter detection mode, the foreign matter is automatically detected until the foreign matter detection mode is released (FIG. 3). , See Figure 5), but foreign matter detection can be performed only when the user deems it necessary. For example, when the release button 18a is fully pressed and the predetermined operation button is pressed, foreign matter is automatically detected, and the release button 18a is fully pressed and the predetermined operation button is not pressed. Occasionally, the configuration is such that foreign matter is not detected.

[0101] Further, the electronic camera of each of the above embodiments may be configured so as to be able to detect that a foreign matter that has been a floating foreign matter has been fixed. For example, the main control units 12, 42, 62, and 82 accumulate correction data obtained when detecting a foreign matter, and recognize that the foreign matter is fixed when the same correction data is continuously obtained a predetermined number of times or more. And notify the user to that effect.

[0102] Further, if necessary, the main control units 12, 42, 62, and 82 are subjected to the type of foreign matter (the size, position, and density of the image of the foreign matter) indicated by the continuously obtained correction data. ) May be notified to the user. Further, in each of the above embodiments, the electronic camera with an interchangeable lens has been described, but the present invention can also be applied to an electronic camera with an integrated lens.

[Effects of the Invention] As described above, according to the present invention, an electronic camera having a foreign matter self-detection function and a control program thereof are realized.

BRIEF DESCRIPTION OF THE DRAWINGS [Fig. 1] Fig. 1 is a configuration diagram of an electronic camera according to a first embodiment and a second embodiment.

FIG. 2 is a diagram showing an example of a setting screen.

FIG. 3 is an operation flowchart of the main control unit 12 of the first embodiment.

FIG. 4 is a diagram illustrating a method for detecting a foreign substance in the first embodiment.

FIG. 5 is an operation flowchart of the main control unit 42 of the second embodiment.

FIG. 6 is a diagram illustrating a method for detecting a foreign substance in the second embodiment.

FIG. 7 is a configuration diagram of an electronic camera according to a third embodiment.

FIG. 8 is a diagram illustrating a method for detecting a foreign substance in the third embodiment.

FIG. 9 is a configuration diagram of an electronic camera according to a fourth embodiment.

FIG. 10 is a diagram illustrating a method for detecting a foreign substance in the fourth embodiment.

[Code description] 10 Electronic camera body 11 Imaging element 11a Cover glass 11b Optical filter 12,42,62,82 Main control unit 13 Display unit 14 AD conversion unit 15 Signal processing unit 16 Buffer memory 18a Release button 18b Operation button 20, 30,40 Interchangeable lens unit 20a, 20b, 30a, 30b, 40a, 40b, 40c Lens 21 Camera shake correction lens 31 Focus adjustment lens 22 Aperture aperture 24,34,44 Position sensor 25,35,45 Optical system drive mechanism 26 Aperture drive means 27,67,87 Optical system control unit 28 Vibration sensor 4a Common pattern (= image of subject) 4b, 4b'Image of foreign matter 5a Evaluation target area