Image reading apparatus, and image reading method

The present invention relates to an image reading device, and more particularly to managing image data read from a document in the image reading device.

In recent years, with the spread of network technology, document data created by scanning from a manuscript has come to be used for various purposes (data transmission, print output via a network, etc.).

In addition, with the spread of color printers and color digital copiers, the colorization of document data is progressing at a rapid pace.

Colorization of document data has become indispensable in various situations such as presentations, and has many advantages, but also has a drawback that it leads to an increase in the amount of information. Handling document data whose capacity has increased due to colorization in this way imposes a heavy load on client PCs and networks. For example, when reading a document in color with a conventional image reader, a color sensor in which RED, GREEN, and BLUE primary color filters are arranged on the light receiving surface, for example, three lines in which the above filters are arranged on the light receiving surface of each line sensor. It is common to use a CCD sensor.

When an A4 size (210 mm x 297 mm) document is read at a resolution of 600 dpi with an image reader using such a conventional 3-line CCD sensor, the image data capacity is 105 MByte (35 MByte x RGB), which is A3 size (A3 size (35 MByte x RGB). When a document of 420 mm x 297 mm) is read, it becomes a large amount of data such as 210 MByte.

Therefore, in order to suppress the increase in the capacity of the document data due to such colorization of the document data, a document data compression technique is required. Document data compression technology is roughly divided into an image part such as a photograph generated in halftone and a line drawing part consisting of characters and thin lines, and the above image part and the line drawing part are compressed separately to obtain the original image. A method of increasing the compression rate of document data without damaging the information is known (see, for example, Patent Document 1 below).<patcit num="1"><text>Japanese Unexamined Patent Publication No. 2-274174</text></patcit>

<p> However, since document data is used for multiple purposes with the recent colorization of document data, not only weight reduction of data but also appropriate and flexible processing of monochrome information and color information is required. ..</p><p> An embodiment of the present invention provides a technique that can contribute to reducing the data capacity of image data read from a document in an image reading device and also contribute to the realization of flexible image processing according to a user's request. The purpose is.</p>

<p> The image reading device according to one aspect of the embodiment includes a first image reading unit that reads a monochrome image of a document by a line sensor having a first resolution, and a second resolution lower than the first resolution. A second image reading unit that reads a color image from the original by the line sensor, and a gradation in a predetermined region in the main scanning direction for each pixel in each image data read by the first image reading unit. The color space frequency is obtained based on the value, and the image belonging to either the first image type in which the brightness resolution should be prioritized or the second image type in which the color reproducibility should be prioritized based on the height of the color space frequency is selected. The discriminant information generation unit that generates discriminant information for discriminating whether or not the image is configured, the pixels of the image data read by the first image reading unit, and the pixels in the image data read by the second image reading unit are described above. The position information acquisition unit that acquires the position information indicating the corresponding position on the same document based on the number of transfer pulses and the pixel in the image data read by the first image reading unit are binarized2. Value processing unit and<u style="single">Said</u>The same position as one of the pixels binarized by the binarization processing unit<u style="single">Read by the second image reading unit in</u>Corresponds to the color information acquisition unit that acquires the color information of the pixels, the position information acquired by the position information acquisition unit, and the color information acquired by the color information acquisition unit for the pixels corresponding to the position information. Further, the position information acquired by the position information acquisition unit is associated with the discrimination information generated by the discrimination information generation unit for the pixels corresponding to the position information, and stored in a predetermined storage area. The configuration is characterized in that it is provided with a storage unit for storing.</p><p><u style="single">Of the embodiment</u>In the image reading method according to one aspect, the original is read in monochrome by a first image reading unit having a line sensor having a first resolution, and a line sensor having a second resolution lower than the first resolution is used. An image is read in color from the original by the second image reading unit having the above, and each pixel in each image data read by the first image reading unit is set to a gradation value in a predetermined region in the main scanning direction. The color space frequency is obtained based on the above, and an image belonging to either the first image type in which the brightness resolution should be prioritized or the second image type in which the color reproducibility should be prioritized is constructed based on the height of the color space frequency. Generates discrimination information to determine whether or not With respect to the pixels of the image data read by the first image reading unit and the pixels in the image data read by the second image reading unit, position information indicating the corresponding positions on the same document is provided based on the number of transfer pulses. The pixels in the image data acquired and read by the first image reading unit are binarized.<u style="single">Said</u>The same position as one of the pixels binarized by the binarization processing unit<u style="single">Read by the second image reading unit in</u>The color information of the pixel is acquired, the acquired position information is associated with the acquired color information for the pixel corresponding to the position information, and the acquired position information corresponds to the position information. The pixel is associated with the discrimination information and stored in the predetermined storage area.</p>

<p> According to the present invention, it is possible to contribute to the reduction of the data capacity of the image data read from the original in the image reading device and to the realization of flexible image processing according to the user's request.</p>

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of an image reader M according to the present embodiment. The image reader M includes a light source 1 that irradiates the original Org with light, a reflector 2 that adjusts the light distribution characteristics for the purpose of irradiating the original Org with uniform light, and a first mirror 3 that receives the reflected light from the original Org. , The reflected light from the 2nd mirror 5 that receives the reflected light from the 1st mirror 3, the 3rd mirror 6 that receives the reflected light from the 2nd mirror 5, and the 3rd mirror 6 that receives the reflected light from the 3rd mirror 6 is transferred to the imaging surface of the 4-line CCD sensor 9. Condensing lens 8 for forming an image, the light energy imaged by the condensing lens 8 is converted into a charge by photoelectric conversion, and the image formed is sequentially output as an electric signal to the outside. 4-line CCD sensors 9, 4 CCD sensor board 10 on which the line CCD sensor 9 is mounted, control board 11 that performs various processing on the CCD output signal output from the CCD sensor board 10, harness 11 that electrically connects the CCD sensor board 10 and the control board 11, white It is provided with a reference plate 13, a platen glass 14 for placing a document Org, and a document holding cover 15.

The first carriage 4 is configured from the light source 1, the reflector 2, and the first mirror 3, and the second mirror 5 and the third mirror 6 to the second carriage 7 are configured. When reading the original Org placed on the platen glass 14, the first carriage 4 moves from the left to the right in FIG. 1 by a driving means (not shown).

At this time, in order not to change the optical path length, which is the distance between the original Org and the image plane of the 4-line CCD sensor 9, the second carriage 7 is moved in the same direction as the first carriage 4 at half the moving speed of the first carriage 4. Move at the speed of.

FIG. 2 is a diagram showing a schematic configuration of the 4-line CCD sensor 9. The 4-line CCD sensor 9 is a color line sensor (second image) consisting of a monochrome line sensor (first image reader) 9K, a red line sensor 9R, a red line sensor 9G, and a blue line sensor 9B. It is equipped with a reading unit).

First, the monochrome line sensor 9K is a shift gate for transferring the charges of the odd-th pixel converted by the photodiode array 9K3 and the photodiode array 9K3, which do not have a color filter on the light receiving surface, to the adjacent analog shift register 9K1. 9K2, analog shift register 9K1 that sequentially transfers the charge to the output side, shift gate 9K4 for transferring the charge of the even-th pixel converted by the photodiode array 9K3 to the adjacent analog shift register 9K5, and the charge to the output side It is equipped with an analog shift register 9K5 that transfers sequentially.

The red line sensor 9R transfers the charge of the photodiode array 9R1 having a blue filter arranged on the light receiving surface, the shift gate 9R2 for transferring the charge of the pixel converted by the photodiode array 9R1 to the adjacent analog shift register 9R3, and the charge. It is equipped with an analog shift register 9R3 that sequentially transfers to the output side. In addition, the green line sensor 9G includes a photodiode array 9G1 in which a blue filter is arranged on the light receiving surface, a shift gate 9G2 for transferring the charge of the pixels converted by the photodiode array 9G1 to an adjacent analog shift register 9G3, and a shift gate 9G2. It is equipped with an analog shift register 9G3 that sequentially transfers charges to the output side.

In addition, the blue line sensor 9B includes a photodiode array 9B1 in which a blue filter is arranged on the light receiving surface, a shift gate 9B2 for transferring the charge of the pixels converted by the photodiode array 9B1 to an adjacent analog shift register 9B3, and It is equipped with an analog shift register 9B3 that sequentially transfers charges to the output side.

The 4-line CCD sensor 9 shown in FIG. 2 has a configuration in which the photodiode array 9K3 and the photodiode array 9B3, the photodiode array 9G3, and the photodiode array 9R3 have different effective pixel counts.

CLK1 and CLK2 that control each analog shift register are in opposite phase, the SHK signal that controls the shift gate 9K2 and the shift gate 9K4, the SHB signal that controls the shift gate 9B2, and the SHG signal that controls the shift gate 9G2. The SHR signal controlling the shift gate 9R2 is input to stop during the'H'period of opening the gate and the period before and after it. In this case, the'H'period is the period during which the gate is opened, but the present invention is not limited to this, and the same operation can be executed during the'L'period.

Further, in the image reader M according to the present embodiment, it is assumed that the number of effective pixels of the photodiode array 9K3 is set to twice that of the photodiode array 9B1, the photodiode array 9G1, and the photodiode array 9R1. For example, when reading a document width of 297 mm, if the photodiode array 9K3 is read at a resolution of 600 dpi (dot per inch), the photodiode array 9B1, the photodiode array 9G1, and the photodiode array 9R1 should be read at a resolution of 300 dpi. become.

FIG. 3 is a graph showing the spectral sensitivity characteristics of the line sensor 9K, and FIG. 4 is a graph showing the spectral sensitivity characteristics of each of the line sensor 9R, the line sensor 9G, and the line sensor 9B.

The 4-line CCD sensor 9 is composed of a line sensor 9K in which a color filter is not arranged on the light receiving surface of the line sensor as described above, and line sensors 9R, 9G and 9B in which a color filter is arranged. The line sensor 9R or line sensor 9G, or line sensor 9B is sensitive only to wavelengths in a specific region, whereas the line sensor 9K has a wavelength region of less than 400 nm to more than 1000 nm. Since the sensitivity is even in the part, the output analog signal amplitude is larger than the analog signal amplitude output from the line sensors R, G, and B.

If the manuscript org is, for example, an A4 size manuscript, it will have an area of 297 mm in the longitudinal direction and 210 mm in the lateral direction. When the document reading operation is performed with the longitudinal direction of the document as the main scanning direction and the minor direction as the sub-scanning direction, the number of effective pixels of the photodiode array of the CCD line sensor 9 is at least 7016 pixels (4677 pixels at 400 dpi). You will need it.

Generally, it is a sensor with 7500 pixels (5000 pixels at 400dpi). In addition, as shown in Fig. 3, the CCD line sensor has an optical shield pixel portion that is shielded from light by aluminum or the like on a part of the photodiode array so that light does not enter the front stage of the effective pixel 7500 pixels, and dummy pixels before and after the effective pixel. Since there is a blank feed part, the number of transfer CLKs exceeding 7500 pixels is required to output all the charges accumulated in the CCD line sensor to the outside.<u style="single">On the contrary, by counting the number of transferred CLKs (clocks), it is possible to acquire the position of the pixel corresponding to the output charge on the line sensor.</u>

Here, assuming that the total of the optical shield pixel portion, the blank feed portion, and the dummy pixel portion outside the effective pixel region described above is 500 in terms of the number of transfer CLKs, the charge accumulated in the CCD line sensor for one line is obtained. Time for 8000 transfer CLKs to output all to the outside of the CCD line sensor<u style="single">Must be</u>In short, that time is the light storage time (tINT) of one line.

Subsequently, the details of the control board 11 will be described. FIG. 5 is a diagram showing a schematic configuration of a control circuit system in the image reader M according to the present embodiment.

The control board 11 is composed of a processing IC 11A such as a CPU, various timing generation circuits 11B, various analog processing circuits 11C, a line memory circuit 11D, and an image processing circuit unit 11E.

In addition to controlling the signal processing system of the CCD sensor 9, the processing IC 11A uses a control signal such as an address bus and a data bus to control the light source 1, and the light source control circuit 17, the first carriage 4, and the second carriage 7. It also controls the drive system control circuit 18 for controlling the motor 19 for moving.

The various timing generation circuits 11B generate signals necessary for driving the CCD line sensor 9, such as SH signals and transfer CLKs 1 and 2 shown in FIG. 2, and signals necessary for various analog processing. The signal required to drive the CCD line sensor 9 generated by the various timing generation circuits 11B is adjusted by the CCD sensor control circuit 10A via the CCD driver 10B, which performs processing for signal amplitude level adjustment and waveform shaping. It is input to the CCD line sensor 9. Here, the CCD sensor control circuit 10A may be configured to be included in the various timing generation circuits 11B. The output from the CCD line sensor 9 is input to various analog processing circuits 11C, and predetermined analog processing is performed. The various analog processing circuits 11C do not necessarily have to be arranged on the control board 11, and there is no functional problem even if they are arranged on the CCD sensor board 10, for example.

As described in FIG. 2, in the CCD line sensor 9, since the line sensors are arranged at predetermined intervals, the reading position of each line sensor is deviated. The line memory circuit 11D corrects the deviation of the reading position. In the image processing circuit unit 11E, in addition to controlling the line memory circuit 11D, processing such as shading correction, enlargement / reduction processing, and LOG conversion performed using the image signal converted into a digital signal is performed. Further, the image processing circuit unit 11E also performs a process of reading a color document and converting the image into an achromatic monochrome signal.

FIG. 6 is a diagram showing a conceptual diagram of a copying device composed of an image reading device M and an image forming device according to the present embodiment.

The copying apparatus uses, for example, an image reader M, a memory as a storage medium, various image processing units 17, a laser optical system 18 using a semiconductor laser, and an electrophotographic process to form an image with toner. It includes an image forming apparatus (printer unit B) including an image forming unit 19, a system control unit that controls all of these, and a control panel that allows the user to directly input data. When communicating between the copying device and external PC1, PC2, PC3, ..., These PCs are connected from the system control unit via a network.

FIG. 7 is a functional block diagram for explaining the image reading device M according to the present embodiment.

The first image reading unit 101 reads a monochrome image from the original at the first resolution (for example, 600 dpi). The second image reading unit 102 reads a color image from the original at a second resolution (for example, 300 dpi) lower than the first resolution. The binarization processing unit 103 binarizes the image data read by the first image reading unit 101.

The discrimination information generation unit 104 determines that each pixel in each image data belongs to either the "first image type" in which the luminance resolution should be prioritized or the "second image type" in which the color reproducibility should be prioritized. Generates discrimination information for determining whether or not it is configured. Specifically, the discrimination information generation unit 104 generates the color space frequency of each pixel in each image data as discrimination information.

The position information acquisition unit 105 acquires position information indicating the corresponding position of each pixel on the document in each image data read from the same document by each of the first image reading unit 101 and the second image reading unit 102. To do.

The color information acquisition unit 106 acquires color information indicating the color of each pixel in each image data. In the present embodiment, the color information acquisition unit 106 is the pixel in the image data read by the first image reading unit 101 based on the image data binarized by the binarization processing unit 103. By adopting the configuration for acquiring the color information of the above, it is possible to contribute to the reduction of the capacity of monochrome image data read at high resolution by the first image reading unit 101 and the data capacity of the color information of the image data. ..<u style="single">That is, each pixel in the image data binarized by the binarization processing unit 103 is represented by either "black" or "white". Therefore, for the pixel represented by either "black" or "white", the color information of the pixel at the same position read by the second image reading unit 102 is acquired. That is, instead of acquiring the color information for all the pixels in the image data read by the second image reading unit 102, the binarization processing is performed in the image data read by the first image reading unit 101. Acquires color information about one of the black and white pixels.</u>

The storage unit 107 discriminates between the position information acquired by the position information acquisition unit 105, the color information acquired by the color information acquisition unit 106 for the pixels corresponding to the position information, and the pixels corresponding to the position information. The discrimination information generated by the information generation unit 104 is associated with the discrimination information and stored in, for example, MEMORY802 or a page memory (predetermined storage area) (not shown). At this time, the storage unit 107 stores each of the above information in the page memory at the same time.

The storage unit 107 groups the position information and the color information based on the discrimination information and stores them in a predetermined storage area. In this way, by storing the position information and color information of pixels belonging to the same image type at consecutive addresses in a predetermined storage area, the pixels that later constitute an image of a specific image type in the image data can be obtained. When performing processing, it is possible to improve the access efficiency to the memory for referring to the position information and the color information stored in the predetermined storage area.

The CPU 801 has a role of performing various processes in the image reader, and also has a role of realizing various functions by executing a program stored in the MEMORY 802. MEMORY802 is composed of, for example, ROM, RAM, etc., and has a role of storing various information and programs used in an image reader.

FIG. 8 is a diagram showing a processing flow in the image reader M according to the present embodiment.

From the image processing circuit unit 11E, a monochrome 600dpi signal and a color signal of 300dpi for each RGB color are aligned by the line memory circuit 11D and output at the same time. For monochrome signals, input to the subsequent binarization processing / pseudo halftone processing (binarization processing unit 103) and the spatial frequency analysis unit (discrimination information generation unit 104) of the image, which will be described later, in order to reduce the weight of the image data. Will be done.

In the page memory PM in the latter stage, the spatial frequency information (discrimination information) generated by the discrimination information generation unit 104 based on the monochrome signal, the monochrome 600dpi binary data, and the Red300dpi signal, Green300dpi signal, and Blue300dpi signal are different from each other. Stored in the area.

Hereinafter, as a reference, a comparison will be made between the conventional data amount when A3 size color information is read and the data amount when read by the image reader M according to the present embodiment. Assuming that the original is A3 size (297 mm × 420 mm), it has 7010 pixels in the main scanning direction and 9912 lines in the sub scanning direction. Here, assuming that the data is 8 bits per color pixel, the required capacity is about 210 MByte for 7010 pixels x 9912 lines x 3 colors.

In the image reader M according to the present embodiment, the capacity of monochrome data becomes about 8.7 MByte at 69.5 Mbit in 7010 pixels × 9912 lines by binarization processing. Further, since the color data capacity has a resolution of 300 dpi, it has 3505 pixels in the main scanning direction and 4956 lines in the sub-scanning direction, and the required capacity is about 52 MByte for 3505 pixels × 4956 lines × 3 colors. Since the spatial frequency data described later is as small as several bytes to several tens of bytes, if ignored here, it is about 210 MByte in the conventional image reading device, whereas it is about 61 MByte (monochrome) in the image reading device according to the present embodiment. 8.7MByte + color 52MByte).

In this way, even if the monochrome and color signals are individually stored in the storage area, the monochrome data is binarized, so that the storage capacity can be reduced by nearly 70%. This leads to a reduction in the amount of data transferred within a certain period of time, and high-speed reading is possible without increasing the speed of the entire circuit, which can contribute to shortening the front job time as a user. Means. Subsequently, the processing in the discrimination information generation unit 104 will be described with reference to FIGS. 9, 10 and 11.

Since the 8-bit image data output from the image processing circuit unit 11E is subjected to shading correction processing, the sensitivity variation of each pixel of the line sensor and the influence of aberration due to the optical system are corrected, but on the document. Since it is not possible to correct singular points such as dust and the roughness of the image due to the original paper itself, filtering is performed in the previous stage of this spatial frequency analysis unit to suppress the roughness (dispersion) generated on the monochrome signal.

In the filter processing, for example, processing such as averaging several pixels in the main scanning direction is performed. After that, the data (color space frequency) is analyzed on a line-by-line basis. For example, the number of times an image change that exceeds the range of image data 100 to 200 LSB is counted, and if the number is equal to or higher than a predetermined threshold (high color space frequency), "character manuscript area (see FIG. 10)". ) Or line art area , and if it is less than a predetermined threshold, it can be determined to be a non-character photographic area (see FIG. 11) . Looking at the flow of processing using the specific images shown in FIGS. 10 and 11, it can be seen that the profile of the character portion changes a lot in the range exceeding the image data 100 to 200 LSB. In addition, although 100 to 200 LSB was set as an explanation this time, it is necessary to set the above judgment range in consideration of the color character and color line data and the roughness after the filter processing.

The discrimination information generation unit 104 performs the above-mentioned processing to generate discrimination information for discriminating between the character area and the photographic area on the image. At this time, when the character area and the photographic area are mixed on one image as shown in FIG. 12, information such as the coordinates of each object is extracted.

For A3 size documents, if the main scanning direction is the x direction and the secondary scanning direction is the y direction, the x direction is from 0 to 8000 (297 mm = 7010 pixels + margin between the front and rear edges), and the y direction is from 0. Assuming 10000 (420mm = 9912 line + margin between front and rear ends), the image information (x, y) can be represented by the coordinates of (x, y) = (0, 0) to (8000, 10000). ..

Taking the character portion 1 shown in FIG. 12 as an example, the main scanning direction is 200 to 6500, the sub scanning direction is 300 to 2500, and the coordinates of the four vertices indicating the region are (200, 300) and (6500, 300). , (200, 2500), (6500, 2500). In order to clarify this area information, it is possible to express it only by diagonal coordinates, and in this case, it can be expressed by START address (200, 300) and END address (6500, 2500).

Since 200 and 300 are decimal numbers, these are expressed in hexadecimal numbers as 00C8 (H) and 012C (H). Similarly, 6500 and 2500 can be represented by 09C4 (H) and 1964 (H) (see Fig. 13).

In addition, image information and coordinates can be represented by adding information representing characters / photographs to the coordinate information. As shown in FIG. 14, when the most significant bit of 16-bit data is used as the image information, the character area is used when the most significant bit = 0 and the character area is used when the most significant bit = 1. Part 1 has a START address 00C8012C and an END address 09C41964.

Similarly, in the photo unit 2, the START address 8FA09770 and the END address 99649F40 can be indicated. In this way, one area can be stored in the page memory as 4-byte data.

FIG. 15 is a diagram for explaining the flow of each image data output from the page memory, and FIGS. 16 and 17 are diagrams for explaining the processing timing related to the resolution conversion process.

The monochrome binary data stored in the page memory is input to the selector (SEL) circuit and resolution conversion circuit in the subsequent stage. The Red multi-value data, Green multi-value data, and Blue multi-value data, which are 300 dpi color data, are input to the resolution conversion process, respectively, and the resolution is converted from 300 dpi to 600 dpi based on the monochrome binary data.

At this time, when the CHA signal indicating the character area shown in FIG. 16 and the PIC signal indicating the photographic area are generated from the spatial frequency data (discrimination information) stored in the page memory by the coordinate conversion counter unit and the CHA signal is valid. The above resolution conversion process is performed. Here, the PVEN (= PageVideoENable) signal shown in FIG. 16 becomes L when the image is valid in the sub-scanning direction, and the HVEN (= HorizontalVideoENable) signal becomes L in the part where the image is valid in the main scanning direction. Is a signal.

That is, according to the present embodiment, in one image data, a high-resolution image is generated in order to display the character portion clearly, and the photographic portion remains at a low resolution so as not to impair the color reproducibility. It is possible to generate an image with a different resolution for each image object (character, line drawing, photograph, etc.), such as generating an image with. In this way, by properly using high-resolution monochrome image data and low-resolution color image data according to the situation, it is possible to provide image data of quality according to the user's request while suppressing the data capacity in the storage area. It becomes possible to do.

In this way, the output resolution of the image can be automatically controlled based on the monochrome 600dpi signal, but since the output content desired by the user is unknown, the output request mode by the control panel, specifically monochrome / By inputting grayscale (monochrome multi-value) / color setting to the selector, monochrome binary, grayscale, and color output can be switched and output.

In the case of color filing, the default setting is a resolution of 300dpi, which is compressed by the system control unit (see Fig. 6) and output to the outside via the network. ) When "High definition" is selected, it is preferable to perform resolution conversion processing on the entire area of the image, perform compression processing on the system control unit as a 600dpi color signal, and output it to the outside via the network. ..

FIG. 18 is a flowchart for explaining a rough flow of processing (image reading method) in the image reading device according to the present embodiment. The first image reading unit 101 reads a monochrome image from the original at the first resolution (first image reading step) (S901). The second image reading unit 102 reads a color image from the original at a second resolution lower than the first resolution (second image reading step) (S902). In the present embodiment, by adopting the above-mentioned 4-line CCD sensor, it is possible to execute the processes of the first image reading step and the second image reading step in parallel.

The binarization processing unit 103 binarizes the image data read in the first image reading step (binarization processing step) (S903). In the discrimination information generation unit 104, which of the first image type in which the luminance resolution should be prioritized and the second image type in which the color reproducibility should be prioritized constitutes an image in which each pixel in each image data belongs. Generate discrimination information for discriminating (discrimination information generation step) (S904). Specifically, the discrimination information generation step generates the color space frequency of each pixel in each image data as discrimination information.

The position information acquisition unit 105 acquires position information indicating the corresponding position of each pixel on the document in each image data read from the same document in each of the first and second image reading steps (position information acquisition step). ) (S905). The color information acquisition unit 106 acquires color information indicating the color of each pixel in each image data (color information acquisition step) (S906). Specifically, the color information acquisition unit 106 acquires the color information of each pixel in the image data read by the first image reading unit 101 based on the image data binarized in the binarization processing step. To do.

The storage unit 107 associates the position information acquired in the position information acquisition step with the color information acquired in the color information acquisition step for the pixels corresponding to the position information, and stores them in a predetermined storage area. (Storage step) (S907). In the storage step, the position information acquired in the position information acquisition step is further associated with the discrimination information generated in the discrimination information generation step for the pixels corresponding to the position information, and stored in a predetermined storage area. You can also let it.

Further, in the storage step, the position information and the color information can be grouped based on the discrimination information and stored in a predetermined storage area. In the storage step, it is desirable to simultaneously store the position information and the color information of the images read in the first and second image reading steps in a predetermined storage area.

Each step in the processing in the image reading device M described above is realized by causing the CPU 801 to execute the image reading program stored in the MEMORY 802.

In the present embodiment, the case where the function for carrying out the invention is recorded in the device in advance has been described, but the present invention is not limited to this, and the same function may be downloaded from the network to the device, or the same function may be recorded. What is stored in the medium may be installed in the device. The recording medium may be in any form as long as it can store a program such as a CD-ROM and can be read by the apparatus. Further, the function obtained by installation or download in advance in this way may be one that realizes the function in cooperation with the OS (operating system) or the like inside the device.

As described above, according to the present embodiment, by simultaneously storing the outputs of the image sensor for high-resolution monochrome reading and the image sensor for low-resolution color reading in the page memory, high-speed transfer of color data becomes possible. .. Further, by performing color resolution conversion in the subsequent processing, it is possible to realize an image output with image processing desired by the user in a short time.

Further, as in the present embodiment, by storing the discrimination information and the pixel position and color information in the storage area in association with each other, the character area and the photographic area when performing desired processing on the image data are performed. It becomes easy to discriminate the image data, and it becomes possible to easily convert the image data to a desired resolution based on the discriminating information. Although the present invention has been described in detail in particular embodiments, it will be apparent to those skilled in the art that various modifications and modifications can be made without departing from the spirit and scope of the invention.

As described in detail above, according to the present invention, it contributes to the reduction of the data capacity of the image data read from the original in the image reading device and also to the realization of flexible image processing according to the user's request. It is possible to provide the technology that can be used.

<figref num="1">It is a figure which shows the schematic structure of the image reading apparatus M by embodiment of this invention.</figref><figref num="2">It is a figure which shows the schematic structure of the 4-line CCD sensor 9.</figref><figref num="3">It is a graph which shows the spectral sensitivity characteristic of a line sensor 9K.</figref><figref num="4">It is a graph which shows the spectral sensitivity characteristic of each of a line sensor 9R, a line sensor 9G, and a line sensor 9B.</figref><figref num="5">It is a figure which shows the schematic structure of the control circuit system in the image reader M by this embodiment.</figref><figref num="6">It is a figure which shows the conceptual diagram of the copying apparatus which consisted of the image reading apparatus M and the image forming apparatus according to this Embodiment.</figref><figref num="7">It is a functional block diagram for demonstrating the image reading apparatus M by this Embodiment.</figref><figref num="8">It is a figure which shows the flow of the process in the image reading apparatus M by this embodiment.</figref><figref num="9">It is a figure for demonstrating the process in the discrimination information generation part 104.</figref><figref num="10">It is a figure for demonstrating the process in the discrimination information generation part 104.</figref><figref num="11">It is a figure for demonstrating the process in the discrimination information generation part 104.</figref><figref num="12">It is a figure which shows the example which the character area and the photographic area are mixed on one image.</figref><figref num="13">It is a figure for demonstrating the method of specifying a character area and a photographic area on an image.</figref><figref num="14">It is a figure for demonstrating the method of specifying a character area and a photographic area on an image.</figref><figref num="15">It is a figure for demonstrating the flow of each image data output from a page memory.</figref><figref num="16">It is a figure for demonstrating the processing timing about the resolution conversion processing.</figref><figref num="17">It is a figure for demonstrating the processing timing about the resolution conversion processing.</figref><figref num="18">It is a flowchart for demonstrating the general flow of the process (image reading method) in the image reading apparatus by this Embodiment.</figref>

Code description

1 light source, 2 reflector, 3 1st mirror, 4 1st carriage, 5 2nd mirror, 6 3rd mirror, 8 condenser lens, 9 4 line CCD sensor, 10 CCD sensor board, 11 control board, 14 platen glass , 15 Original holding cover, 101 1st image reading unit, 102 2nd image reading unit, 103 2 digitizing processing unit, 104 discrimination information generation unit, 105 position information acquisition unit, 106 color information acquisition unit, 107 storage unit , 801 CPU.