JP4962375B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus that reads an image.

  Conventionally, in order to adjust the resolution of image reading as in the image reading device described in Patent Document 1, pixel data of odd-numbered photodiodes among the photodiodes provided in the line sensor is output by one CCD column. However, there is known a configuration in which pixel data from even-numbered photodiodes is output by the other CCD column. With such a configuration, when reading an image at a low resolution, image data is generated from pixel data output from one of the two CCD columns, and when an image is read at a high resolution. Image data can be generated from the pixel data output from both of the two 2CCD rows. Note that when reading an image with high resolution, it is necessary to rearrange the pixel data output from the two CCD columns in the original order of the photodiodes. In the image reading apparatus described in Patent Document 1, when pixel data by each photodiode is stored in the image memory, the pixel data is directly stored in the storage area of the image memory corresponding to the original order of the photodiodes. The pixel data is rearranged. Furthermore, since pixel data from odd-numbered photodiodes and even-numbered photodiodes are output by two independent CCD columns, pixel data from adjacent odd-numbered and even-numbered photodiodes can be output almost simultaneously. The pixel data can be easily rearranged by writing the output pixel data into the image memory in the original photodiode order.

JP 2004-56283 A (paragraphs 0031 to 0036, 0067 to 0081, FIGS. 2 and 3 etc.)

  Incidentally, in recent years, a line sensor provided with a plurality of CCDs in the main scanning direction has been improved in resolution, and a line sensor provided with two photodiodes for each CCD has been developed. As described above, in a line sensor that has been increased in resolution by providing two photodiodes for each CCD, after pixel data from one photodiode provided in each CCD is output to all of the CCDs. Otherwise, pixel data from the other photodiode cannot be output. Therefore, when the line sensor is used as a reading unit included in the image reading apparatus to read an image, it is necessary to rearrange pixel data by each photodiode as in the conventional image reading apparatus described above.

  On the other hand, when storing the line data output by the reading means in the image memory, in order to increase the processing speed, the data transfer unit is preset as an unchangeable fixed value, and the line data is set in the set data transfer unit. Is generally known in the art. With this configuration, the line data output from the reading unit is stored in the image memory for each predetermined data transfer unit. Therefore, the pixel data cannot be rearranged by directly storing the pixel data in the corresponding storage area of the image memory as described above, and a technical improvement has been demanded.

  The present invention has been made in view of the above problems, and rearranges the pixel data constituting the line data when a data transfer unit is predetermined to the image memory of the line data output by the reading unit. An object of the present invention is to provide an image reading apparatus capable of performing the above.

  In order to achieve the above object, a printing apparatus according to the present invention includes an image reading apparatus that transmits image data acquired by reading an image to an external device via a data transmission unit. At least one line sensor in which N (N is a natural number of 2 or more) CCDs in the main scanning direction are arranged in parallel in the main scanning direction (X is a natural number) is provided in each CCD. A line formed by repeating outputting X pixel data by the nth (n is a natural number) photoelectric conversion element and outputting X pixel data by the (n + 1) th photoelectric conversion element. Scanning means for sequentially outputting data by scanning the image in the sub-scanning direction substantially perpendicular to the main scanning direction by the line sensor, and reading the image; An image memory having a first work area for temporarily holding, a second work area for temporarily holding the line data, and a third work area for temporarily holding the line data; and the reading means outputs The data transfer means for selectively transferring the line data to any one of the first to third work areas using M (M is a natural number of 2 or more) bytes as a data transfer unit; and transferring the line data by the data transfer means. The line data held in any of the first to third work areas is rearranged in the order of the photoelectric conversion elements provided in the line sensor while rearranging the order of the pixel data constituting the line data. Data rearranging means for selectively transferring to any of the first to third work areas, and the data stored in any of the first to third work areas. Data reading means for sequentially reading the line data after the rearrangement by the data rearranging means to the data transmission means until the data size of the remaining data of the line data becomes smaller than M bytes, using M bytes as a data transfer unit. A buffer means for temporarily holding the remaining data, and a data transfer destination of the line data by each of the data transfer means and the data rearranging means, among any of the first to third work areas, Memory management means for setting an area in which the line data is not held, and the remaining data held in the buffer means are set by the memory management means as a data transfer destination at the time of rearrangement by the data rearrangement means Any of the first to third work areas may be provided by the data rearranging means. And a data management means for transferring the data before sorting is started.

  In the invention configured as described above, the line data output from the reading unit is any one of the first to third work areas set by the memory management unit using M bytes as a data transfer unit by the data transfer unit. Forwarded to Then, the line data transferred by the data transfer unit is sorted by the memory management unit while rearranging the order of the pixel data constituting the line data by the data rearrangement unit while rearranging the order of the photoelectric conversion elements provided in the line sensor. Since the data is transferred to one of the set first to third work areas, the data transfer unit of the line data output by the reading unit to the image memory is predetermined as M bytes. The pixel data constituting the line data can be rearranged.

  In addition, when the data sorting unit rearranges the line data in any of the first to third work areas when the output of the next line data in the sub-scanning direction of the image is started from the reading unit. If there is no area, that is, if there is an unused area, the unused area is set as a transfer destination by the data transfer means for the next line data by the memory management means, and the next line data is stored in the unused area. Transferred by data transfer means. Further, when the line data is held in any one of the first to third work areas, and the line data is transferred to one of the remaining work areas by the data transfer means, If the work area is unused, the unused area is set by the memory management means as the transfer destination of the line data when the pixel data is rearranged by the rearranging means, and the pixel data is rearranged in the unused area. While being transferred. As described above, if any of the first to third work areas is unused, the memory management unit sets the data transfer destination of the line data by the data transfer unit or the data rearrangement unit. Since the transfer of line data and the rearrangement of the pixel data by the data rearranging means can be performed simultaneously, it is very efficient and the processing speed can be increased.

  Further, the line data after rearranged by the data rearranging means held in any of the first to third work areas has the data size of the remaining data of the line data with M bytes as the data transfer unit by the data reading means. Data is successively read out to the data transmission means until it becomes smaller than M bytes. Therefore, when the data size of the remaining data is smaller than M bytes, the read of the rearranged line data to the data transmitting means is finished, so that the remaining data having a data size smaller than M bytes as a data transfer unit is read. By doing so, it is possible to reliably prevent the data that becomes garbage together with the remaining data from being transmitted to the external device via the data transmission means.

  The remaining data is temporarily held by the buffer means, and the remaining data held in the buffer means is stored in the memory as a data transfer destination when the data rearrangement means rearranges the next line data by the data management means. The data is transferred to any one of the first to third work areas set by the management unit before the sorting by the data sorting unit is started. When the rearrangement of the next line data by the data rearranging means is completed, the remaining data is transferred by the data reading means together with the rearranged line data and before the rearranged line data. It will be read by the transmission means. Therefore, even when the data transfer unit from the image memory to the data transmission unit is predetermined as M bytes, the image data (line data) transmitted to the external device via the data transmission unit is converted into pixel data. Can be reliably transmitted to an external device in a highly accurate state.

  FIG. 1 is a diagram showing a configuration of a scanner device 10 which is an embodiment of an image reading device of the present invention. FIG. 2 is an enlarged view of a main part of the scanner device 10 of FIG. 1 and shows a configuration of the image sensor 36. FIG. 3 is a diagram showing the configuration of the AFE 27. FIG. 4 is a timing chart showing the reading timing by dot sequential. FIG. 5 is a timing chart showing the reading timing by line sequential. In this scanner device 10, the image of the read document placed on the reading surface 12 is scanned in the sub-scanning direction by the image sensor 36 of the built-in carriage 30, and the obtained image data is read. It is configured to transmit to an external device such as a user personal computer (PC) 50 via an interface (I / F) 29 (corresponding to “data transmission means” of the present invention) 29.

  As shown in FIG. 1, the scanner device 10 includes a carriage 30 that reads an image of a read document placed on a reading surface 12 that is a glass plate, and a control unit 20 that controls the entire device. In addition, the scanner device 10 includes a white reference plate 16 provided on the carriage 30 side of the upper surface 14 of the housing, a transparent original light source 32 that is disposed above the read original and is used when reading the transparent original, and the carriage 30. And a drive motor 39 that moves the motor.

  The carriage 30 is disposed below the read original, and includes a reflective original light source 31 that irradiates light on the original placed on the reading surface 12, and a mirror 33 and a condenser lens 34 that reflect or transmit light reflected from the original. And an image sensor 36 for reading an image by receiving the image via the. The reflective original light source 31 and the transparent original light source 32 are configured such that light from one or a plurality of white LEDs is linearly applied to the reading surface 12. Note that white light may be emitted from a red LED, a green LED, a blue LED, a mercury lamp, or the like.

  2, the image sensor 36 includes a first line sensor 36R that outputs a red (R) signal in which a plurality of photoelectric conversion elements are arranged in parallel in the main scanning direction, and a plurality of photoelectric conversion elements. A second line sensor element array 36G that outputs a green (G) signal arranged in parallel in the main scanning direction and a blue (B) signal that outputs a plurality of photoelectric conversion elements arranged in parallel in the main scanning direction. 3 line sensor 36B. The first line sensor 36R is a photoelectric conversion element constituting one pixel, and converts a plurality of photodiodes 41a1, 41a2, 41b1, 41b2, 41c1, 41c2,... And a plurality of CCDs 42a, 42b, 42c... Capable of transferring charges received from the photodiodes in the horizontal direction. Similarly to the first line sensor 36R, the second line sensor 36G includes photodiodes 43a1, 43a2, 43b1, 43b2, 43c1, 43c2,... And CCDs 44a, 44b, 44c. Similarly to the first and second line sensors 36R and 36G, the third line sensor 36B includes photodiodes 45a1, 45a2, 45b1, 45b2, 45c1, 45c2,... And CCDs 46a, 46b, 46c,. . In the present embodiment, the whole of the plurality of photodiodes 41a1... Is referred to as a photodiode 41, and the whole of the plurality of CCDs 42a. Further, the whole of the plurality of photodiodes 43 a 1... Is referred to as a photodiode 43, and the whole of the plurality of CCDs 44 a. Further, the whole of the plurality of photodiodes 45 a 1... Is called a photodiode 45, and the whole of the plurality of CCDs 46 a. The CCDs 42, 44, and 46 have an electronic shutter function, and the electronic shutter function allows the electric charge to escape to a substrate (not shown). As shown in FIG. 2, in this embodiment, two photodiodes are provided for one CCD to constitute each line sensor 36R, 36G, 36B. The number of photodiodes is not limited to two, and an arbitrary number of photodiodes can be provided according to the resolution of image reading. Further, the number of CCDs constituting the line sensors 36R, 36G, 36B can be arranged in parallel in the main scanning direction according to the resolution of image reading and the configuration of the scanner device 10.

  In addition, the carriage 30 includes a carriage belt 38 laid between a drive motor 39 attached to one end of the housing of the scanner device 10 and a driven roller 38 a attached to the other end of the housing. It is configured to be movable in the carriage movement direction (sub-scanning direction) as it is driven. Then, by moving the carriage 30, line data read by scanning the image of the read original placed on the reading surface 12 in the sub-scanning direction substantially orthogonal to the main scanning direction by the image sensor 36 will be described later. Sequentially output to the AFE 27. Further, although the image sensor 36 in which the line sensors 36R, 36G, and 36B for each color are arranged in a row in the main scanning direction is taken as an example, two or more rows of line sensors for each color may be arranged.

  The control unit 20 includes a CPU 23, a ROM 24 that stores processing programs and various tables, a RAM 22b that temporarily stores data such as line data output from the image sensor 36, a writing of image data to the RAM 22b, and an output from the RAM 22b. A RAM control unit 22a that controls reading of image data, an interface (I / F) 29 such as a USB interface, a LAN in interface, a wireless LAN interface, and an interface according to the IEEE 1394 standard that can be connected to an external device such as the PC 50, and an image From the CCD controller 25 that drives and controls the sensor 36, a timing generator (TG) 26 that outputs the start timing of various operations of the image sensor 36 to the image sensor 36, and the image sensor 36 An analog front end (AFE) 27 that amplifies the applied electric signal and converts it into a digital signal, and image processing that creates digital image data by executing predetermined processing such as shading correction and gamma correction on the signal input from the AFE 27 Each of which is capable of inputting / outputting various signals such as a control command signal and an image data signal via the bus line 21.

  Various signals such as a reading command from the PC 50 are input to the control unit 20 via the I / F 29, and the control unit 20 outputs a lighting signal to the reflective original light source 31 and the transparent original light source 32, and driving. In addition to outputting a drive signal to the motor 39, gain adjustment of the AFE 27, output of a digital image data signal to the I / F 29, and a main clock to the CCD controller 25 are generated. Further, the main controller 21 outputs a lighting signal to the reflective original light source 31 and the transparent original light source 32, a drive signal to the drive motor 39, a gain adjustment signal to the AFE 27, and a digital image data signal to the I / F 29. Then, a main clock and a read command signal to the CCD controller 25 are output.

  The CCD controller 25 outputs, to the TG 26, a drive signal corresponding to the charge readout start timing of the image sensor 36 created based on the main clock generated by the control unit 20, and the image sensor 36 is dot-sequentially. A point-sequential control unit 25a for driving and a line-sequential control unit 25b for driving the image sensor 36 in a line-sequential manner are provided.

  As shown in FIG. 4, “dot sequential” means that the first photodiode 41a1 included in the first CCD 42a included in the first line sensor 36R and the first CCD 44a included in the second line sensor 36G. A first photodiode 43a1, a first photodiode 45a1 included in the first CCD 46a included in the third line sensor 36B, a first photodiode 41b1 included in the second CCD 42b included in the first line sensor 36R, Each photodiode 41 included in each of the line sensors 36R, 36G, and 36B in this order, such as the first photodiode 43b1 included in the second CCD 44b included in the second line sensor 36G. , 43, 45 It refers to be read. When the charges accumulated in the first photodiodes of the CCDs 42, 44, and 46 are read out, the second photodiode 41a2 and the second photodiodes of the first CCD 42a included in the first line sensor 36R are next. The second photodiode 43a2 included in the first CCD 44a included in the line sensor 36G, the second photodiode 45a2 included in the first CCD 46a included in the third line sensor 36B, and the second photodiode included in the first line sensor 36R. The second photodiode 41b2 of the CCD 42b, the second photodiode 43b2 of the second CCD 44b included in the second line sensor 36G, and the second photodiode of each CCD 42, 44, 46 are used. The accumulated charge is Capacitors 36R, 36G, are read in the order of 36B.

  Specifically, as shown in FIG. 4, the CCD controller 25 outputs a shift signal to all the line sensors 36R, 36G, 36B (time t1). Then, all the line sensors 36R, 36G, and 36B start accumulating charges for the read image at the same timing. Next, when the read start timing is reached, a shift signal and a drive signal are output to all the line sensors 36R, 36G, 36B (time t2). Then, in each of the line sensors 36R, 36G, 36B, the charges accumulated in the first photodiodes 41a1, 41b1,..., 43a1, 43b1,. , 44, 46, and the charges moved to the CCDs 42, 44, 46 are in the order of the first line sensor 36 R, the second line sensor 36 G, and the third line sensor 36 B, and the photodiodes of the line sensors 36 R, 36 G, 36 B. , 43a1, 43b1,..., 45a1, 45b1,..., 45a1, 45b1,. When the next read start timing is reached, a shift signal and a drive signal are output to all the line sensors 36R, 36G, 36B (time t3). Then, in each of the line sensors 36R, 36G, 36B, the charges accumulated in the second photodiodes 41a2, 41b2,..., 43a2, 43b2,. , 44, 46, and the charges moved to the CCDs 42, 44, 46 are in the order of the first line sensor 36 R, the second line sensor 36 G, and the third line sensor 36 B, and the photodiodes of the line sensors 36 R, 36 G, 36 B. .., 43a2, 43b2,..., 45a2, 45b2,... Are read in the order of arrangement in the main scanning direction (time t3 to t4). Thus, in the dot sequence, the image sensor 36 receives “R1”, “G1”, “B1”, “R3”, “G3”, “B3”..., “R2” “G2” “B2” “R4” “G4” “B4”. The charges are output in the order of “... If all the charges are output from the line sensors 36R, 36G, and 36B, accumulation of the next charge is started. The numbers next to RGB indicate the arrangement order of the photodiodes provided in the line sensors 36R, 36G, and 36B.

  As shown in FIG. 5, “line sequential” means that all the charges accumulated in the order of the photodiodes 41 a 1, 41 b 1, 41 c 1... Included in the first line sensor 36 R are read from the first line sensor 36 R, All the charges accumulated in the order of the photodiodes 43a1, 43b1, 43c1,... Included in the second line sensor 36G are read from the second line sensor 36G, and the photodiodes 45a1, 45b1, 45c1,. After all the accumulated charges are read out from the third line sensor 36B, and all the charges accumulated in the order of the photodiodes 41a2, 41b2, 41c2, etc. included in the first line sensor 36R are read out from the first line sensor 36R, Photodiode included in the second line sensor 36G All the charges accumulated in the order of 43a2, 43b2, 43c2,... Are read from the second line sensor 36G, and the charges accumulated in the order of the photodiodes 45a2, 45b2, 45c2,. Read all from.

  Specifically, as shown in FIG. 5, first, the CCD controller 25 outputs a shift signal to the first line sensor 36R (time t8). Then, the first line sensor 36R starts accumulating charges for the read image. Next, when the read start timing of the first line sensor 36R is reached, a shift signal and a drive signal are output to the first line sensor 36R, and a shift signal is output to the second line sensor 36G (time t9). Then, the charges accumulated in the photodiodes 41a1, 41b1, 41c1,... Are moved to the CCD 42 (time t9), the charges moved to the CCD 42 are read, and the second line sensor 36G starts accumulating charges for the read image. (Time t9 to t11). When the next read start timing is reached, a shift signal and a drive signal are output to the first line sensor 36R (time t10). Then, the charges accumulated in the photodiodes 41a2, 41b2, 41c2,... Are moved to the CCD 42 (time t10), and the charges moved to the CCD 42 are read out. Subsequently, when the read start timing of the second line sensor 36G is reached, a shift signal and a drive signal are output to the second line sensor 36G, and a shift signal is output to the third line sensor 36B (time t11). Then, the reading of charges from the CCD 42 is finished, the charges accumulated in the photodiodes 43a1, 43b1, 43c1,... Are moved to the CCD 44 (time t11), the charges moved to the CCD 44 are read, and the third line sensor 36B Accumulation of the charge for the read image is started (time t11 to t13). When the next read start timing is reached, a shift signal and a drive signal are output to the second line sensor 36G (time t12). Then, the charges accumulated in the photodiodes 43a2, 43b2, 43c2,... Are moved to the CCD 44 (time t12), and the charges moved to the CCD 44 are read out.

  Subsequently, when the read start timing of the third line sensor 36B is reached, a shift signal and a drive signal are output to the third line sensor 36B (time t13). Then, the reading of charges from the CCD 44 is completed, the charges accumulated in the photodiodes 45a1, 45b1, 45c1,... Are moved to the CCD 46 (time t13), and the charges moved to the CCD 46 are read (time t13 to t14). When the next read start timing is reached, a shift signal and a drive signal are output to the third line sensor 36B (time t14). Then, the charges accumulated in the photodiodes 45a2, 45b2, 45c2,... Move to the CCD 46 (time t14), and the charges moved to the CCD 46 are read out. When the reading of charges from the CCD 46 is completed, the output of line data for one line for each of “R”, “G”, and “B” is completed. As described above, in the line sequential manner, the charge accumulation times of the first line sensor 36R, the second line sensor 36G, and the third line sensor 36B are the same accumulation time, but the charge accumulation start timing and the CCDs 42, 44, 46 The readout start timings for reading out the charges transferred to are set at different timings. Thus, in the line sequential manner, the charges for one line from the image sensor 36 are “R1”, “R3”, “R5”, “R2”, “R4”, “R6”, “G1”, “G3”, “G5”,. G2 "" G4 "" G6 "...," B1 "" B3 "" B5 "..." B2 "" B4 "" B6 "... are output in this order. The numbers next to RGB indicate the arrangement order of the photodiodes provided in the line sensors 36R, 36G, and 36B.

  As described above, in this embodiment, the line sensors 36R, 36G, and 36B are configured by arranging a plurality of CCDs in which two photodiodes constituting one pixel are provided in the main scanning direction. However, the pixel data from the first photodiodes 41a1, 41b1,..., 43a1, 43b1,..., 45a1, 45b1,. .., 43a2, 43b2,..., 45a2, 45b2,..., 45a2, 45b2,... Are all output to form line data, and the line data formed in this way is sub-scanned in the line sensors 36R, 36G, and 36B. Are sequentially output in accordance with the scanning. Note that when three or more photodiodes are provided in each CCD to form the line sensors 36R, 36G, and 36B, each CCD with an nth (n is a natural number) photodiode provided in each CCD is used. The line data is formed by repeating the output of all the pixel data corresponding to the number and outputting all the pixel data corresponding to the number of each CCD by the (n + 1) th photodiode.

  In this embodiment, line data for three colors is output from the first to third line sensors 36R, 36B, and 36G by one reading of one line of the image by the image sensor 36. The line data of the book is combined and handled as the line data of the first line. Unless the line data output by the line sensors 36R, 36G, and 36B is distinguished from each other and clearly handled, the line data of the three colors “R”, “G”, and “B” are combined to form the first line. This is called line data. Further, when the read original is other than negative, the CCD controller 25 has a charge accumulation time (exposure time) of the first line sensor 36R, the second line sensor 36G, and the third line sensor 36B of 1: 1. Is set to a ratio of 1: 1, and when the read original is negative, the charge accumulation time of the first line sensor 36R, the second line sensor 36G, and the third line sensor 36B is set to a ratio of 1: 2: 3. Set to be. With such a configuration, when the read original is a negative transparent original including many dark areas with small gradations, the second line sensor 36G and the third line sensor that read green and blue that are difficult to transmit light. It is possible to obtain a sufficiently large output value of each color by setting the charge accumulation time of 36B to a longer time than usual and driving the image sensor 36 to accumulate the charge.

  Since the arrangement order of the pixel data constituting the line data formed as described above is different from the actual arrangement order of the photodiodes 41, 43, 45, the pixels constituting the formed line data Although it is necessary to rearrange the data, the rearrangement of the pixel data will be described in detail later.

  The TG 26 outputs the output timing of the shift signal to the image sensor 36. The image sensor 36 is configured to move the charge accumulated in the photodiode to the CCD when the shift signal is input from the TG 26, and to output the charge in the CCD to the AFE 27 when the drive signal is input from the TG 26. Has been.

  As shown in FIG. 3, the AFE 27 reads the electric charge read from the image sensor 36 as an image analog signal through a correlated double sampler (CDS) processing circuit 27a while suppressing noise and amplifies it to an appropriate signal level. After 27b, the A / D converter 27c converts the digital signal to about 10 to 16 bits. The AFE 27 has a configuration in which charges from the first line sensor 36R, the second line sensor 36G, and the third line sensor 36B are switched and input by a changeover switch 27d. In this scanner device 10, the AFE 27 inputs charges while switching the three element rows, so that the reading speed at which the charges accumulated in the image sensor 36 are read from the image sensor 36 is determined by the AFE 27 or the image processing unit 28. Is set to a value suitable for the processing speed.

  The image processing unit 28 performs predetermined processing on the digital signal input from the AFE 27 to generate image data, or generates white reference data and black reference data for shading correction. A gamma correction unit, a document discrimination unit, an exposure time setting unit (not shown), respectively.

  The RAM (corresponding to the “image memory” of the present invention) 22b includes a first work area 22b1 for temporarily holding line data, a second work area 22b2 for temporarily holding line data, and a temporary line data. And a third work area 22b3 to be held. The RAM control unit 22a is configured to selectively transfer the line data output from the AFE 27 to any of the first to third work areas 22b1, 22b2, and 22b3 using 16 bytes as a data transfer unit. .

  The CPU 23 transfers the line data before rearrangement transferred by the RAM control unit 22a and held in any of the first to third work areas, the line sensors 36R and 36G according to the arrangement order of the pixel data constituting the line data. , 36B is arranged in the order of arrangement of the photodiodes 41, 43, 45, and the data control unit 23a is configured to selectively transfer to any one of the first to third work areas. . That is, by outputting line data in a dot-sequential manner, “R1” “G1” “B1” “R3” “G3” “B3”..., “R2” “G2” “B2” “R4” “G4” “ The pixel data arranged in the order of “B4” are “R1”, “G1”, “B1”, “R2”, “G2”, “B2”, “R3”, “G3”, “B3”, “R4”, “G4”, “B4”,. The data is transferred while being rearranged. Further, by outputting line data in line sequential order, “R1” “R3” “R5”... “R2” “R4” “R6”..., “G1” “G3” “G5”… “G2” “G4” “G6”..., “B1” “B3” “B5”... “B2” “B4” “B6”..., “R1” “R2” “R3” “R4” “R5” "R6" ..., "G1" "G2" "G3" "G4" "G5" "G6" ..., "B1" "B2" "B3" "B4" "B5" "B6" ... Data is transferred. The transfer destination of the line data from the AFE 27 and the transfer destination of the line data while rearranging the pixel data by the data control unit 23a are any of the first to third work areas 22b1, 22b2, and 22b3. An area in which line data is not held, that is, an unused area is set by the RAM control unit 22a as a data transfer destination.

  In addition, the line data after the pixel data is rearranged by the data control unit 23a held in any of the first to third work areas 22b1, 22b2, and 22b3 is stored as 16 bytes by the RAM control unit 22a. As a transfer unit, the data is sequentially read to the I / F 29 until the data size of the remaining data of the line data becomes smaller than 16 bytes.

  Further, the RAM 22b is configured with a buffer 22b4 that temporarily holds the remaining data of the line data, and the remaining data that has not been transmitted to the I / F 29 because the data size is smaller than 16 bytes is stored in the RAM 22b. The data is temporarily stored in the buffer by the control unit 23a. Then, the data control unit 23a transfers the pixel data to any one of the first to third work areas 22b1, 22b2, and 22b3 set by the RAM control unit 22a as the data transfer destination when the pixel data is rearranged. The remaining data held in the buffer 22b4 before the start is transferred. Since line data is transferred to the I / F 29 by the RAM control unit 22a using 16 bytes as a data transfer unit, the buffer 22b4 may be configured to temporarily hold data having a data size of at least 15 bytes. In this embodiment, the data size of 16 bytes is set as a value fixed as hardware as a data transfer unit of data transfer from the AFE 27 to the RAM 22b and data transfer from the RAM 22b to the I / F 29. However, the data size is not limited to 16 bytes, and the hardware can be designed by arbitrarily setting a data transfer unit with a data size of 2 bytes or more.

  As described above, the carriage 30, the mirror 33, the condenser lens 34, the image sensor 36, and the AFE 27 constitute the “reading unit” of the present invention. The RAM control unit 22a functions as the “data transfer unit”, “data read unit”, and “memory management unit” of the present invention. The buffer 22b4 configured in the RAM 22b functions as the “buffer unit” of the present invention. Further, the data control unit 23a configured in the CPU 23 functions as “data rearranging means”, “buffer means”, and “data management means” of the present invention. Next, the rearrangement of pixel data will be described in detail with reference to FIGS.

  6 is a conceptual diagram showing the writing of pixel data into the RAM 22b by the first photodiodes 41a1, 41b1,..., 43a1, 43b1,..., 45a1, 45b1,. 7 is a conceptual diagram showing the writing of pixel data into the RAM 22b by the second photodiodes 41a2, 41b2,..., 43a2, 43b2,..., 45a2, 45b2,. FIG. 8 is a conceptual diagram showing the writing of the next line data to the RAM 22b and the rearrangement of the pixel data. FIG. 9 is a conceptual diagram showing rearrangement of pixel data of the next line. In the present embodiment, as described above, the line data for one line includes three colors “R”, “G”, and “B” output from the line sensors 36R, 36G, and 36B of the image sensor 36. Line data is included. However, for the sake of simplicity, only the processing of single-color line data output from any one of the line sensors 36R, 36G, and 36B will be described below. However, processing of line data of other colors is described. Since this is the same as the process described below, the description of the process is omitted.

  As shown in FIG. 6, first, the first work area 22b1 is created by the first RAM 41a1, 41b1, ..., 43a1, 43b1, ..., 45a1, 45b1, ... output from the AFE 27 by the RAM controller 22a. Set as the data transfer destination. Then, the pixel data corresponding to the reading range input from the PC 50 or the like via the I / F 29 is transferred to the first work area by the RAM control unit 22a. At this time, the data transfer unit from the AFE 27 to the RAM 22b is set as a data size of 16 bytes. Accordingly, the pixel data other than the read range is also transferred to the first work area 22b1 by the RAM control unit 22a together with the pixel data of the read range so that the data size of all the pixel data to be transferred is a multiple of 16 bytes. Transferred.

  Next, as shown in FIG. 7, of the pixel data by the second photodiodes 41a2, 41b2,..., 43a2, 43b2, ..., 45a2, 45b2,. Pixel data is transferred to the first work area 22b1 by the RAM controller 22a. At this time, in the same manner as described above, the pixel data other than the readout range is also the first work area 22b1 together with the pixel data in the readout range so that the data size of all the pixel data to be transferred is a multiple of 16 bytes. To the RAM controller 22a.

  Subsequently, as shown in FIG. 8, the second work area 22b2 is set as a transfer destination of the pixel data in the rearrangement of the pixel data by the data control unit 23a. Then, among the pixel data stored in the first work area 22b by the data control unit 23a, the pixel data corresponding to the read range is rearranged in the original order of the photodiodes 41, 43, 45, and the second work area. 22b2. At this time, the third work area, which is an unused area, is set by the RAM control unit 22a as the transfer destination of the next line data from the AFE 27, and the RAM control unit 22a performs pixel data transfer from the AFE 27 in the same manner as described above. Is transferred to the third work area 22b3.

  Then, as shown in FIG. 9, the rearranged pixel data stored in the second work area 22b2 is sequentially I / O until the data size of the remaining data becomes smaller than 16 bytes with 16 bytes as a data transfer unit. The data is transferred to F29 by the RAM control unit 22a. At this time, in this embodiment, whether or not the remaining data is generated by transferring the rearranged pixel data to the I / F 29 is calculated by the data control unit 23a prior to the data transfer to the I / F 29. It is configured. When remaining data is generated, the data control unit 23a stores the remaining data in the buffer 22b4 prior to data transfer to the I / F 29.

  On the other hand, since the first work area 22b1 becomes an unused area due to the completion of the rearrangement shown in FIG. 8, the RAM control unit 22a includes pixels constituting the next line data stored in the third work area 22b3. It is set as a transfer destination of pixel data when data is rearranged by the data control unit 23a. At this time, prior to the rearrangement of the pixel data stored in the third work area 22b3, the data control unit 23a stores the remaining data of the previous line held in the buffer 22b4 in the first work area 22b1. It is configured. Next, image reading processing will be described with reference to FIGS. Although omitted in the above description, the present embodiment is configured to read the image by moving the carriage 30 in the sub-scanning direction at a constant speed. At this time, the line data output from the AFE 27 is temporarily stored in a buffer (not shown) and then stored in the RAM 22b. With this configuration, the line data sequentially output from the AFE 27 is temporarily stored in a buffer (not shown), thereby rearranging the pixel data constituting the line data and transmitting the image data to an external device. Even when the speed is slower than the image reading speed of the scanner device 10 (the moving speed of the carriage 30), the image can be read without stopping the carriage 30. Further, the reference numerals of time t indicating the respective timings in FIGS. 10 to 12 are independent in the respective drawings.

<First Example of Image Reading Process>
FIG. 10 is a timing chart showing an example of the image reading process, and shows an example in which the reading range of the image in the main scanning direction is relatively wide. As shown in “reading line” in FIG. 10, the scanner device 10 can read line data of each line at each timing L1, L2, L3..., That is, transfer line data from the AFE 27 to the RAM 22b by the RAM 22a. It is configured. At the timing of time t = t0, the transfer destination of the line data L1 from the AFE 27 is set in the first work area 22b1 by the RAM control unit 22a, and the line data L1 is transferred to the first work area 22b1.

  Next, when the transfer of the line data L1 to the first work area 22b1 is completed at the timing of time t = t1, the pixel data associated with the rearrangement of the pixel data constituting the line data L1 by the data control unit 23a. The second work area 22b2 is set as the transfer destination, and the sorting process is started. At the time t = t2, the RAM control unit 22a sets the transfer destination of the line data L2 from the AFE 27 to the third work area 22b3 that is an unused area, and the line data L2 is set to the third work area 22b3. Transferred. Subsequently, DMA (Direct Memory Access) transfer of the rearranged line data L1 ′ to the external device (I / F 29) by the RAM control unit 22a is started at time t = 3, and the data control unit The remaining data is stored in the buffer 22b4 by 23a. Further, the RAM controller 22a sets the transfer destination of the line data L3 from the AFE 27 to the first work area 22b1 which is an unused area, and the line data L3 is transferred to the first work area 22b1.

  Next, at the timing of time t = t4, the DMA transfer of the rearranged line data L1 ′ to the external device ends, and the data control unit 23a performs the data transfer associated with the rearrangement of the pixel data constituting the line data L2. A second work area 22b2 that is an unused area is set as a transfer destination of pixel data. At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the second work area 22b2. Subsequently, at the timing of time t = t5, DMA transfer of the rearranged line data L2 ′ to the external device by the RAM control unit 22a is started, and the remaining data is stored in the buffer 22b4 by the data control unit 23a. The Further, the RAM control unit 22a sets the transfer destination of the line data L4 from the AFE 27 to the third work area 22b3 which is an unused area, and the line data L4 is transferred to the third work area 22b3.

  Next, at the timing of time t = t6, DMA transfer of the rearranged line data L2 ′ to the external device is completed, and the data control unit 23a performs the transfer of the pixel data constituting the line data L3. A second work area 22b2 that is an unused area is set as a transfer destination of pixel data. At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the second work area 22b2. Subsequently, DMA transfer of the rearranged line data L3 ′ to the external device by the RAM control unit 22a is started at time t = t7, and the remaining data is stored in the buffer 22b4 by the data control unit 23a. The Further, the RAM controller 22a sets the transfer destination of the line data L5 from the AFE 27 to the first work area 22b1 that is an unused area, and the line data L5 is transferred to the first work area 22b1.

  Next, at the timing of time t = t8, the DMA transfer of the rearranged line data L3 ′ to the external device is completed, and the data control unit 23a performs the transfer of the pixel data constituting the line data L4. A second work area 22b2 that is an unused area is set as a transfer destination of pixel data. At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the second work area 22b2. Thereafter, the same processing is repeated until the image reading is completed.

<Second Example of Image Reading Process>
FIG. 11 is a timing chart showing an example of the image reading process, and shows an example in which the reading range of the image in the main scanning direction is relatively narrow. As shown in “reading line” in FIG. 11, the scanner device 10 can read line data of each line at each timing L1, L2, L3..., That is, transfer line data from the AFE 27 to the RAM 22b by the RAM 22a. It is configured. At the timing of time t = t0, the transfer destination of the line data L1 from the AFE 27 is set in the first work area 22b1 by the RAM control unit 22a, and the line data L1 is transferred to the first work area 22b1.

  Next, when the transfer of the line data L1 to the first work area 22b1 is completed at the timing of time t = t1, the pixel data associated with the rearrangement of the pixel data constituting the line data L1 by the data control unit 23a. The second work area 22b2 is set as the transfer destination, and the sorting process is started. At time t = t2, DMA transfer of the rearranged line data L1 ′ to the external device (I / F 29) by the RAM control unit 22a is started, and the remaining data is buffered by the data control unit 23a. 22b4.

  Next, at time t = t3, the RAM control unit 22a sets the transfer destination of the line data L2 from the AFE 27 to the first work area 22b1 that is an unused area, and the line data L2 is set to the first work area 22b1. Forwarded to Next, at the timing of time t = t4, the second work area 22b2, which is an unused area, is set as a transfer destination of the pixel data accompanying the rearrangement of the pixel data constituting the line data L2 by the data control unit 23a. The At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the second work area 22b2.

  Then, at the timing of time t = t5, DMA transfer of the rearranged line data L2 'to the external device by the RAM control unit 22a is started, and the remaining data is stored in the buffer 22b4 by the data control unit 23a. Thereafter, the same processing is repeated until the image reading is completed.

<Third Example of Image Reading Process>
FIG. 12 is a timing chart illustrating an example of image reading processing, and illustrates an example in which the transfer rate of image data to an external device via the I / F 29 is relatively slow. As shown in “reading line” in FIG. 12, the scanner device 10 can read line data of each line at each timing L1, L2, L3..., That is, transfer of line data from the AFE 27 to the RAM 22b by the RAM 22a. It is configured. At the timing of time t = t0, the transfer destination of the line data L1 from the AFE 27 is set in the first work area 22b1 by the RAM control unit 22a, and the line data L1 is transferred to the first work area 22b1.

  Next, when the transfer of the line data L1 to the first work area 22b1 is completed at the timing of time t = t1, the pixel data associated with the rearrangement of the pixel data constituting the line data L1 by the data control unit 23a. The second work area 22b2 is set as the transfer destination, and the sorting process is started. At time t = t2, DMA transfer of the rearranged line data L1 ′ to the external device by the RAM control unit 22a is started, and the remaining data is stored in the buffer 22b4 by the data control unit 23a. .

  Next, at time t = t3, the RAM control unit 22a sets the transfer destination of the line data L2 from the AFE 27 to the first work area 22b1 that is an unused area, and the line data L2 is set to the first work area 22b1. Forwarded to Next, when the transfer of the line data L1 to the first work area 22b1 is completed at the timing of time t = t4, the pixel data associated with the rearrangement of the pixel data constituting the line data L2 by the data control unit 23a. A third work area 22b3, which is an unused area, is set as the transfer destination. At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the third work area 22b3.

  At time t = t5, the remaining data calculated prior to the start of DMA transfer of the rearranged line data L2 ′ to the external device by the RAM control unit 22a is stored in the buffer 22b4 by the data control unit 23a. Stored. Next, at the timing of time t = t6, the transfer destination of the line data L3 from the AFE 27 is set to the first work area 22b1 which is an unused area by the RAM control unit 22a, and the line data L3 is set to the first work area 22b1. Forwarded to Then, at the timing of time t = t7, DMA transfer of the rearranged line data L1 ′ to the external device is completed, and the pixel associated with the rearrangement of the pixel data constituting the line data L3 by the data control unit 23a. A second work area 22b2 that is an unused area is set as a data transfer destination. At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the second work area 22b2. Also, DMA transfer of the rearranged line data L2 'to the external device by the RAM control unit 22a is started.

  Next, at the timing of time t = t8, the remaining data calculated prior to the start of the DMA transfer of the rearranged line data L3 ′ to the external device by the RAM control unit 22a is stored in the buffer 22b4 by the data control unit 23a. Stored in Subsequently, at time t = 9, the RAM control unit 22a sets the transfer destination of the line data L2 from the AFE 27 to the first work area 22b1 that is an unused area, and the line data L4 is set to the first work area 22b1. Forwarded to Then, at the timing of time t = t10, the DMA transfer of the rearranged line data L3 ′ to the external device is completed, and the pixel associated with the rearrangement of the pixel data constituting the line data L4 by the data control unit 23a. A third work area 22b3, which is an unused area, is set as a data transfer destination. At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the third work area 22b3. Also, the DMA transfer of the rearranged line data L3 'to the external device by the RAM control unit 22a is started.

  Next, at the timing of time t = t11, the remaining data calculated prior to the start of the DMA transfer of the rearranged line data L4 ′ to the external device by the RAM control unit 22a is stored in the buffer 22b4 by the data control unit 23a. Stored in Further, the RAM controller 22a sets the transfer destination of the line data L5 from the AFE 27 to the first work area 22b1 that is an unused area, and the line data L5 is transferred to the first work area 22b1. Then, at the timing of time t = t12, the DMA transfer of the rearranged line data L4 to the external device ends, and the pixel data associated with the rearrangement of the pixel data constituting the line data L5 by the data control unit 23a. As a transfer destination, the second work area 22b2 that is an unused area is set. At this time, prior to the start of the rearrangement process, the remaining data held in the buffer 22b4 by the data control unit 23a is transferred to the second work area 22b2. Also, DMA transfer of the rearranged line data L5 'to the external device by the RAM control unit 22a is started. Thereafter, the same processing is repeated until the image reading is completed.

  As described above, in this embodiment, the line data output from the AFE 27 is any one of the first to third work areas 22b1, 22b2, and 22b3 set by the RAM control unit 22a using 16 bytes as a data transfer unit. Is transferred to the area. The line data transferred by the RAM control unit 22a is sent from the photodiodes 41, 43, and 45 provided in the line sensors 36R, 36G, and 36B by the data control unit 23a. While being rearranged in the arrangement order, it is transferred to one of the first to third work areas 22b1, 22b2, and 22b3 set by the RAM control unit 22a. Therefore, even when the data transfer unit of the line data output from the AFE 27 to the RAM 22b is predetermined as 16 bytes, the pixel data constituting the line data can be rearranged.

  In addition, when the data control unit 22a rearranges the pixel data, when output of the next line data in the sub-scanning direction of the image is started from the AFE 27, one of the first to third work areas 22b1, 22b2, and 22b3 is selected. If there is an area in which line data is not stored, that is, if there is an unused area, the unused area is set as a transfer destination of the next line data by the RAM control unit 22a, and the next unused area is next. Are transferred by the RAM control unit 22a. Also, when the line data is held in any of the first to third work areas 22b1, 22b2, and 22b3, and the line data is transferred by the RAM control unit 22a to one of the remaining work areas. On the other hand, if the remaining other work area is unused, the unused area is set by the RAM control unit 22a as the transfer destination of the line data when the data control unit 23a rearranges the pixel data. Sorting is performed. As described above, if any of the first to third work areas 22b1, 22b2, and 22b3 is unused, the unused area is the transfer destination of the line data by the RAM control unit 22a, or the pixel data by the data control unit 23a. Since the transfer of the line data by the RAM control unit 22a and the rearrangement of the pixel data by the data control unit 23a can be performed at the same time, it is very efficient and speeds up the processing. Can be planned.

  In addition, the line data after rearrangement by the dedata control unit 23a held in any of the first to third work areas 22b1, 22b2, and 22b3 is made up of 16 bytes as a data transfer unit by the RAM control unit 22a. The remaining data is sequentially read to the I / F 29 until the data size becomes smaller than 16 bytes. Therefore, when the data size of the remaining data becomes smaller than 16 bytes, the read of the rearranged line data to the I / F 29 is completed, so that the remaining data having a data size smaller than 16 bytes as a data transfer unit is read. By doing so, it is possible to reliably prevent the data that becomes garbage together with the remaining data from being transmitted to the external device such as the PC 50 via the I / F 29.

  The remaining data is temporarily held in the buffer 22b4, and the remaining data held in the buffer 22b4 is set by the RAM control unit 22a as a data transfer destination when the data control unit 23a rearranges the next line data. The data is transferred to one of the first to third work areas 22b1, 22b2, and 22b3 before the sorting by the data control unit 23a is started. When the rearrangement of the next line data by the data control unit 23a is completed, the remaining data is read to the I / F 29 together with the rearranged line data and before the rearranged line data. Will be. Therefore, even when the data transfer unit from the RAM 22b to the I / F 29 is predetermined as 16 bytes, image data (line data) transmitted to an external device such as the PC 50 via the I / F 29 is changed. The pixel data can be reliably transmitted to the external device in a highly accurate state without missing.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, the image reading apparatus capable of reading a color image has been described as an example. However, the present invention may be applied to a monochrome image reading apparatus including one line sensor.

  Further, the setting of the charge accumulation time, the charge accumulation start timing, the charge read timing, and the like of each of the line sensors 36R, 36G, and 36B described in the above embodiment is an example, and is limited to the above setting. is not. These settings can be optimized according to various conditions such as the type of read document, the sensitivity of the photodiodes 41, 43, and 45, the processing speed of the AFE 27, and the overall processing time. In the above-described embodiment, the scanner device 10 is described as an example of the image reading device of the present invention. However, the image reading device of the present invention may be a multi-function printer provided with a printing device or a FAX device. It may be. In the above-described embodiment, the buffer 22b4 functioning as the “buffer unit” of the present invention is configured in a part of the RAM 22b. However, the buffer 22b4 is not limited to the RAM 22b, and the remaining data is stored. If possible, the buffer 22b4 may be configured in any way. For example, a cache provided in the CPU 23 may be used as the buffer 22b4. Alternatively, the buffer 22b4 may be provided in the control unit 20 individually.

1 is a diagram illustrating a configuration of a scanner device that is an embodiment of an image reading device of the present invention. FIG. FIG. 2 is an enlarged view of a main part of the scanner device of FIG. 1. The figure which shows the structure of AFE. The timing chart which shows the reading timing by dot sequential. 6 is a timing chart showing reading timing by line sequential. The conceptual diagram which shows writing to RAM of line data. The conceptual diagram which shows writing to RAM of line data. FIG. 4 is a conceptual diagram illustrating writing of line data to a RAM and rearrangement of pixel data. The conceptual diagram which shows rearrangement of pixel data. 6 is a timing chart illustrating an example of image reading processing. 6 is a timing chart illustrating an example of image reading processing. 6 is a timing chart illustrating an example of image reading processing.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Scanner apparatus (image reading apparatus), 22a ... RAM control part (data transfer means, data reading means, memory management means), 22b ... RAM (image memory), 22b1 ... 1st work area, 22b2 ... 2nd work area 22b3 ... third work area, 22b4 ... buffer (buffer means) 23a ... data control unit (data rearrangement means, buffer means, data management means), 27 ... AFE (reading means), 29 ... I / F (data transmission) Means), 30 ... Carriage (reading means), 33 ... Mirror (reading means), 34 ... Condensing lens (reading means) 41, 43, 45 ... Photodiode (photoelectric conversion element), 36 ... Image sensor (reading means) , 36R, 36G, 36B ... line sensors

Claims (1)

In an image reading apparatus that transmits image data acquired by reading an image to an external device via a data transmission unit,
At least one line sensor in which N (N is a natural number of 2 or more) photoelectric conversion elements constituting one pixel are arranged in parallel with X (X is a natural number) in the main scanning direction. And output X pixel data by the nth (n is a natural number) photoelectric conversion element provided in each CCD, and output X pixel data by the (n + 1) th photoelectric conversion element. Reading means for sequentially outputting line data formed by repeating this by scanning the line sensor in a sub-scanning direction substantially orthogonal to the main scanning direction and reading the image;
An image memory having a first work area for temporarily holding the line data, a second work area for temporarily holding the line data, and a third work area for temporarily holding the line data;
Data transfer means for selectively transferring the line data output by the reading means to any one of the first to third work areas using M (M is a natural number of 2 or more) bytes as a data transfer unit;
The line data transferred by the data transfer means and held in any of the first to third work areas, and the photoelectric conversion provided in the line sensor for the arrangement order of pixel data constituting the line data Data rearranging means for selectively transferring to any one of the first to third work areas while rearranging the elements in the order of arrangement;
The line data stored in any one of the first to third work areas after being rearranged by the data rearranging means is set to M bytes as a data transfer unit, and the data size of the remaining data of the line data is M. Data reading means for sequentially reading to the data transmitting means until it becomes smaller than a byte;
Buffer means for temporarily holding the remaining data;
Memory management means for setting an area in which the line data is not held among any of the first to third work areas as a data transfer destination of the line data by the data transfer means and the data rearranging means. When,
The remaining data held in the buffer unit is stored in the data arrangement in any of the first to third work areas set by the memory management unit as a data transfer destination at the time of rearrangement by the data rearrangement unit. An image reading apparatus comprising: a data management unit that transfers data before sorting by the switching unit is started.

Images