JP4339462B2 - Color image reading apparatus and memory controller used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color image reading device that reads a color original image using a three-line image sensor, and a memory that controls a correction memory used in the color image reading device in order to correct a line gap of the three-line image sensor. It relates to the controller.
[0002]
[Prior art]
In general, in a color image reading apparatus such as a color scanner, an original image is read using an RGB (red green blue) three-line image sensor. In a color image reading apparatus using a 3-line image sensor, an original image is scanned by a 3-line image sensor to obtain RGB analog signals corresponding to the original image, and these are converted into RGB digital signals by an A / D converter. Conversion is performed to correct an output timing shift caused by a line gap, which will be described below, and an RGB digital signal is output.
[0003]
As shown in the conceptual diagram of FIG. 5, the 3-line image sensor includes three line sensors including an R sensor, a G sensor, and a B sensor. Each line sensor is physically separated from a predetermined line. It is arranged and integrated. For this reason, the images simultaneously read by the respective line sensors are images at line positions separated by a predetermined line interval. The physical line interval between the line sensors is generally called a line gap.
[0004]
Therefore, when the original image is sequentially read in line units in the BGR order, for example, if the line gap is 8 lines, B reads 8 lines earlier than G and 16 lines earlier than R. Similarly, G reads a line 8 lines earlier than R. For this reason, B is delayed by 16 lines with respect to R, and G is delayed by 8 lines with respect to R so that RGB digital signals corresponding to the same pixel on the same line are output simultaneously. There is.
[0005]
In order to correct the deviation in output timing due to the line gap, for example, the image reading apparatus disclosed in Japanese Patent Laid-Open No. 10-336470 uses a memory for correcting the line gap and outputs it earlier by the number of lines corresponding to the line gap. The digital signal to be stored is temporarily stored in the correction memory, and when the digital signal output at the latest timing is output, the digital signal stored in the correction memory is read and the RGB digital signals are output simultaneously. Like to do.
[0006]
In this case, as shown in the conceptual diagram of FIG. 6, the correction memory is used by dividing the area for each color component of RGB in advance and fixing the area. In the illustrated example, the R digital signal output at the latest timing is also temporarily stored in the correction memory. However, the output timing of the BG digital signal is matched with the output timing of the R digital signal. If there is, it is not always necessary to store the R digital signal in the correction memory.
[0007]
In this way, when the correction memory area is divided and used in a fixed manner, the amount of digital signal data to be stored in the correction memory changes when the reading resolution or the size of the original image changes. Can not respond flexibly. Further, since the line gap width varies depending on the line sensor used, the required memory capacity is different, and there is a problem that the fixed area cannot be used or an area larger than necessary may be required.
[0008]
The above problem depends on the specifications of the color image reading apparatus, the maximum reading resolution, the maximum size of the original image that can be read, and the line gap of the three-line image sensor used in the color image reading apparatus. However, it is necessary to redesign the memory controller that controls the correction memory for each product, which is very important when manufacturing multiple products with various specifications. It takes time and costs.
[0009]
[Problems to be solved by the invention]
An object of the present invention is to provide a color image reading apparatus capable of dealing with various reading resolutions, document image sizes, and line gaps, and a correction memory used in the color image reading apparatus, in view of the problems based on the prior art. It is to provide a memory controller for controlling the above.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a color image reading apparatus that scans and sequentially reads a document image line by line for each RGB.
RGB that extend in the main scanning direction and are arranged in parallel at a predetermined line interval from each other, read the original image line by line for each RGB, and output RGB analog signals corresponding to the read image 3-line image sensor,
A light source extending in the main scanning direction along the three-line image sensor and irradiating the document image;
Conveying means for relatively transported in the sub-scanning direction substantially Cartesian and the original image and the 3-line image sensor and the light source in the main scanning direction,
An A / D converter that converts the RGB analog signals into corresponding RGB digital signals;
A correction memory for temporarily holding the RGB digital signals and adjusting the output timing of the RGB digital signals;
A memory controller that controls writing of the RGB digital signals to the correction memory and reading of the RGB digital signals from the correction memory;
The memory controller is configured to write the RGB digital signals at the same pixel position on the same line at the same pixel positions on the lines that are separated from each other by the predetermined line interval so as to write the RGB digital signals at the same pixel position on successive memory addresses. The present invention provides a color image reading apparatus characterized by controlling an image memory.
Here, the memory controller first applies the RGB digital signal to the RGB digital signal at the same pixel position on the same line output from the A / D converter at a timing shifted by a time corresponding to the predetermined line interval. Among the signals, the color signal from which the first effective digital signal is obtained is the color signal from which the second and third effective digital signals from among the RGB digital signals in the correction memory are obtained. Write to the address that skips the address to write the signal,
Next, after writing the color signal for obtaining the first effective signal for the predetermined line, the color signal for obtaining the second effective signal is written for the color signal for obtaining the first effective signal. Write to the address next to the address,
Further, after writing the color signal for obtaining the second effective signal for the predetermined line, the color signal for obtaining the third effective signal is used as the second color signal to be obtained. It is preferable to control the correction memory so that RGB digital signals at the same pixel position on the same line are written to successive memory addresses by writing to the address adjacent to the written address.
[0011]
In addition, the present invention provides color image reading for outputting RGB digital signals corresponding to an original image read by a three-line image sensor having a line gap with a predetermined line interval by correcting the line gap using a correction memory. In the apparatus, a memory controller that controls writing of the RGB digital signals to the correction memory and reading of the RGB digital signals from the correction memory,
The correction memory is controlled so as to write RGB digital signals at the same pixel position on the same line in consecutive lines supplied to the consecutive memory addresses for the simultaneously supplied RGB digital signals at the same pixel position on the lines separated by the predetermined line interval. A memory controller is provided.
Here, the RGB digital signal is received at a timing shifted by a time corresponding to the predetermined line,
First, among the RGB digital signals, the color signal from which the first effective digital signal is obtained is converted into the second and third effective digital signals of the RGB digital signal in the correction memory. Write to the address that skips the address to write the signal of the color from which the signal is obtained,
Next, after writing the color signal for obtaining the first effective signal for the predetermined line, the color signal for obtaining the second effective signal is written for the color signal for obtaining the first effective signal. Write to the address next to the address,
Further, after writing the color signal for obtaining the second effective signal for the predetermined line, the color signal for obtaining the third effective signal is used as the second color signal to be obtained. It is preferable to control the correction memory so that RGB digital signals at the same pixel position on the same line are written to successive memory addresses by writing to the address adjacent to the written address.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a color image reading apparatus of the present invention and a memory controller used therefor will be described in detail based on preferred embodiments shown in the accompanying drawings.
[0013]
FIG. 1 is a conceptual block diagram of a color image reading apparatus according to an embodiment of the present invention. The illustrated color image reading apparatus 10 scans a document image 12 in units of lines for each of RGB (red, green, and blue) and sequentially reads them. The timing generator 14, the line sensor 16, the light 18, the motor 20, The controllers 22 and 24, an A / D (analog / digital) converter 26, an image processing unit 28, a memory controller 30, a correction memory 32, and an interface 34 are included.
[0014]
In the color image reading apparatus 10, the timing generator 14 first generates a timing control signal such as a clock signal. In FIG. 1, illustration is omitted in order to avoid complication of the drawing, but the timing control signal generated by the timing generator 14 is supplied to each part of the color image reading apparatus 10, and each part has a timing. It operates in synchronization with the timing control signal supplied from the generator 14.
[0015]
Subsequently, each of the line sensors 16 is an RGB three-line image sensor configured by integrating RGB line sensors that extend in the main scanning direction and are physically arranged in parallel at a predetermined line interval. is there. The line sensor 16 reads the document image 12 in units of lines for each RGB, and outputs RGB analog signals corresponding to the read images. The RGB analog signals output from the line sensor 16 are supplied to the A / D converter 26.
[0016]
The light 18 is a light source extending in the main scanning direction along the line sensor 16 and irradiates the document image 12 under the control of the controller 22. In the case of a reflective document, the light emitted from the light 18 enters the document image 12, and the reflected light from the surface of the document image 12 is received by the line sensor 16 and read. In the case of a transmissive document, the light emitted from the light 18 is incident on the document image 12 and the transmitted light transmitted through the document image 12 is received by the line sensor 16.
[0017]
Motor 20 is made of an example of a conveying means, under the control of the controller 24, relatively transported in the sub-scanning direction substantially Cartesian an original image 12 and the line sensor 16 and light 18 in the main scanning direction. The illustrated example is an example in which the document image 12 is fixed and the line sensor 16 and the light 18 are moved by the motor 20, but conversely, the line sensor 16 and the light 18 are fixed and the document image 12 is moved. Alternatively, both may be moved simultaneously.
[0018]
By moving the original image 12 and the line sensor 16 and the light 18 extending in the main scanning direction relatively by the motor 20, the original image 12 is scanned two-dimensionally line by line for each RGB by the line sensor 16. And read. The RGB line sensors constituting the line sensor 16 simultaneously output RGB analog signals corresponding to images at line positions separated by a predetermined line interval corresponding to the line gap.
[0019]
Subsequently, the A / D converter 26 converts the RGB analog signals supplied from the line sensor 16 into corresponding RGB digital signals. The RGB digital signals output from the A / D converter 26 are supplied to the next image processing unit 28.
The image processing unit 28 performs various types of image processing on the RGB digital signals supplied from the A / D converter 26. The RGB digital signals after image processing are supplied from the image processing unit 28 to the memory controller 30.
[0020]
The memory controller 30 controls writing of RGB digital signals supplied from the image processing unit 28 to the correction memory 32 and reading of RGB digital signals from the correction memory 32. The memory controller 30 corrects the memory 32 for correction so as to write RGB digital signals at the same pixel position on the same line to consecutive addresses with respect to the RGB digital signals at the same pixel position on the lines that are separated from each other by a predetermined line interval. To control.
[0021]
Finally, the correction memory 32 is for temporarily holding the RGB digital signal after image processing in order to adjust the output timing of the RGB digital signal. Under the control of the memory controller 30, RGB digital signals at the same pixel position on the same line written at successive addresses in the correction memory 32 are sequentially read out and transferred to a personal computer (PC) or the like via the interface 34. The
[0022]
The color image reading apparatus 10 of the present invention basically has the other parts except that the memory controller 30 of the present invention, which will be described in detail below, is adopted as the memory controller 30 for controlling the correction memory 32. Any conventionally known one can be applied. The color image reading apparatus 10 of the present invention is basically as described above, and can be applied to various devices including a color image reading unit such as a color scanner, a color copy, and a color facsimile.
[0023]
Next, the memory controller 30 of the present invention will be described in detail.
As described above, the memory controller 30 controls the writing of the RGB digital signals supplied from the image processing unit 28 to the correction memory 32 and the reading of the RGB digital signals from the correction memory 32. As shown in the block configuration conceptual diagram of FIG. 2, an address counter 36, a controller 38, and a memory interface 40 are included.
[0024]
In the memory controller 30 of the illustrated example, first, the address counter 36 is controlled by the controller 38, and an address for writing the RGB digital signal supplied from the image processing unit 28 shown in FIG. An address for reading an RGB digital signal from the correction memory 32 is generated. The controller 38 operates based on the timing signal supplied from the timing generator 14.
[0025]
The memory interface 40 controls switching between writing of the RGB digital signals to the correction memory 32 and switching of reading of the RGB digital signals from the correction memory 32. The RGB digital signals after the image processing are performed. Is written in the write address supplied from the address counter 36, and the RGB digital signal is read from the read address in the correction memory 32 supplied from the address counter 36.
[0026]
FIG. 3 shows a conceptual diagram of the correction memory 32 in a state where RGB digital signals are written. In the same figure, if the RGB digital signal sequence of one horizontal line conceptually corresponds to one horizontal line of the document image 12, the RGB digital signal sequence of the first row is the first line of the document image 12. The RGB digital signals corresponding to each of the pixels are RGB digital signals corresponding to the second and subsequent lines of the original image 12, respectively.
[0027]
For each of the RGB digital signal columns in each row, the leftmost RGB digital signal is an RGB digital signal corresponding to the leftmost pixel of the corresponding line of the document image 12, and similarly, the second from the left. The subsequent RGB digital signals are RGB digital signals corresponding to the second and subsequent pixels from the left side of the same line. In this way, the RGB digital signal of each pixel on the same line of the document image 12 is written to successive memory addresses in the correction memory 32.
[0028]
That is, conceptually, for example, the line direction of the original image 12 is made to correspond to the memory address corresponding to the vertical direction of the correction memory 32 in FIG. 2, and the pixel direction of the original image 12 is set to the horizontal direction of the correction memory 32. Considering each corresponding to the corresponding memory address, in the correction memory 32 , RGB digital signals corresponding to each pixel of each line of the original image 12 are converted into consecutive memory addresses intuitively corresponding to each pixel. Will be written.
[0029]
For example, the distance between the RGB line sensors of the line sensor 16, that is, the line gap between R, G, and B, is 8 lines each, and an A4-sized reflective original is used as the original image 12 in the BGR order with a resolution of 400 dpi in the longitudinal direction The procedure for sequentially writing RGB digital signals to the correction memory 32 and reading the RGB digital signals from the correction memory 32 will be described by taking an example of reading sequentially in the scanning direction).
[0030]
First, when an A4 size reflection original is positioned on a mounting table such as a glass plate and reading is started as the original image 12, the motor 20 causes the line sensor 16 and the light 18 extending in the main scanning direction to move in the sub scanning direction. Moved to. At this time, the light emitted from the light 18 enters the original image 12, and the reflected light from the surface of the original image 12 is received by the line sensor 16. Thus, the document image 12 is read by the line sensor 16 in units of lines for each of RGB.
[0031]
The line sensor 16 sequentially outputs RGB analog signals corresponding to each pixel in one row of the read document image 12. The RGB analog signals are supplied to the A / D converter 26 and converted into corresponding RGB digital signals, and various image processes are performed in the image processing unit 28. Thereafter, the RGB digital signals after image processing are supplied to the memory controller 30, and writing to the correction memory 32 and reading from the correction memory 32 are controlled.
[0032]
The A4 size original image 12 is approximately 8.3 inches in length in the short side direction (main scanning direction), and there are 3320 pixels per line when read at a resolution of 400 dpi. Therefore, the line gap of 8 lines corresponds to 3320 × 8 = 26560 pixels. The memory controller 30 shifts the RGB digital signals supplied at the same time by eight lines, and stores the RGB digital signals of the pixels on the same line at successive memory addresses of the correction memory 32.
[0033]
When reading a document image in the order of BGR, first, a B digital signal is obtained, and an effective G digital signal is obtained after 8 lines corresponding to the line gap. Then, an effective R digital signal is obtained after 8 lines, and thereafter a BGR digital signal is obtained simultaneously. However, as described above, the BGR digital signals obtained at the same time are shifted in time output timing corresponding to eight lines with a line gap.
[0034]
A description will be given below with reference to a conceptual diagram of one embodiment showing a procedure for writing RGB digital signals to the correction memory 32 shown in FIG.
In the case of the present embodiment, the memory controller 30 first writes a valid B digital signal sequentially into the correction memory 32 as shown in FIG. At this time, an address for writing the R and G digital signals is skipped and the B digital signal is written.
[0035]
After the B digital signals are written for eight lines, the B and G digital signals are successively written in the correction memory 32 as shown in FIG. At this time, the B digital signal is written in the same manner after writing for 8 lines. Also, the G digital signal is written to the address (the previous address in the illustrated example) adjacent to the memory address corresponding to the pixel position eight lines before the B digital signal.
[0036]
Subsequently, after writing the B digital signal for 16 lines and the G digital signal for 8 lines into the correction memory 32, as shown in FIG. 4C, the B, G, and R digital signals are output. Write. Similarly, the B digital signal is written after 16 lines are written, and the G digital signal is written after 8 lines are written. The R digital signal is written to an address adjacent to the memory address corresponding to the pixel position eight lines before the G digital signal.
[0037]
In this way, when the BGR digital signals for 17 lines, 9 lines, and 1 line are written, the RGB digital signals in the first column of the correction memory 32 are the first line of the original image 12. In this state, RGB digital signals at the same pixel position are written in consecutive memory addresses in the first column of the correction memory 32. 4B and 4C, one of the BGR digital signals supplied at the same time is marked with a circle for easy understanding.
[0038]
Thereafter, in this embodiment, RGB digital signals corresponding to the pixels in the first row of the correction memory 32, that is, the first line of the document image 12, are sequentially read out from the correction memory 32 shown in FIG. And transferred to a PC or the like via the interface 34. Similarly, after the BGR digital signal for one line is written and the RGB digital signal for one line is read repeatedly, the output timing of the RGB digital signal is adjusted (matched).
[0039]
For writing the BGR digital signal for the next one line, the B digital signal is overwritten in the first column of the correction memory 32, and the G and R digital signals are written in the tenth and first columns, respectively. Written. In the case of the present embodiment, the G and R digital signals are also written in the first column of the correction memory 32 after the data for the 17th line, which is the maximum capacity of the correction memory 32, is written. Will be overwritten.
[0040]
As described above, in the color image reading apparatus to which the memory controller of the present invention is applied, the area of the correction memory 32 is used without being fixed for each RGB, so various line gap intervals and the reading resolution of the original image 12 are used. It is possible to flexibly cope with the document size and the like. Further, since RGB digital signals are stored in continuous addresses in the reading order, reading control is easy. In particular, when a DRAM is used as the correction memory 32, reading in a high-speed page mode is possible. .
[0041]
When writing a digital signal, for example, the number of B digital signal write pixels is counted, and when the number of pixels corresponding to the line gap is reached, the G digital signal write is started. It is also possible to read out data from the line sensor 16 because a synchronization signal is always required for each line. Therefore, the G digital signal can be written by counting this synchronization signal for the number of lines corresponding to the line gap. You may make it start.
[0042]
In the above embodiment, the capacity for temporarily storing the R digital signal in the correction memory is one line. However, the present invention is not limited to this, and may be appropriately determined as necessary. In addition, if the G and B digital signals corresponding to the pixels on the same line are read from the correction memory 32 at the timing when the R digital signal is supplied from the image processing unit 28, the R digital signal is read. Is not necessarily temporarily stored in the correction memory 32.
[0043]
The color image reading apparatus of the present invention is basically as described above.
The color image reading apparatus and the memory controller of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various improvements and modifications may be made without departing from the gist of the present invention. Of course.
[0044]
【The invention's effect】
As described above in detail, the present invention is a color image reading apparatus that outputs RGB digital signals corresponding to an original image read by a three-line image sensor by correcting a line gap using a correction memory. , A memory controller that controls writing of RGB digital signals to the correction memory and reading of the RGB digital signals from the correction memory, and the same pixel positions of lines that are simultaneously supplied and separated by a predetermined line interval For the RGB digital signals, the correction memory is controlled so that the RGB digital signals at the same pixel position on the same line are written to successive memory addresses.
As described above, according to the present invention, since the correction memory area is used without being fixed for each RGB, it is possible to flexibly cope with various line gap intervals, document image reading resolution, document size, and the like. System design is easy and it leads to cost reduction. In addition, according to the present invention, since RGB digital signals are stored in continuous addresses in the order of reading, it is easy to control reading. In particular, if a DRAM is used as a correction memory, high-speed page mode can be achieved. Reading can be performed, and even when scanning a specific range, there is an advantage that the operation can be performed without changing the area of the memory for correction only by detecting the synchronization signal.
[Brief description of the drawings]
FIG. 1 is a conceptual block diagram of an embodiment of a color image reading apparatus according to the present invention.
FIG. 2 is a conceptual block diagram of a memory controller according to an embodiment of the present invention.
FIG. 3 is a conceptual diagram of an embodiment of a correction memory in a state where a digital signal is written.
FIGS. 4A, 4B, and 4C are conceptual diagrams of an embodiment showing a procedure for writing a digital signal to a correction memory. FIGS.
FIG. 5 is a conceptual block diagram illustrating an example of a color image reading apparatus.
FIG. 6 is a conceptual diagram of an example of a correction memory.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Color image reading apparatus 12 Original image 14 Timing generator 16 Line sensor 18 Light 20 Motor 22, 24, 38 Controller 26 A / D converter 28 Image processing part 30 Memory controller 32 Correction memory 34 Interface 36 Address counter 40 Memory interface

Claims (4)

A color image reading apparatus that scans a document image in units of lines for each RGB and sequentially reads the original image,
RGB that extend in the main scanning direction and are arranged in parallel at a predetermined line interval from each other, read the original image line by line for each RGB, and output RGB analog signals corresponding to the read image 3-line image sensor,
A light source extending in the main scanning direction along the three-line image sensor and irradiating the document image;
Conveying means for relatively transported in the sub-scanning direction substantially Cartesian and the original image and the 3-line image sensor and the light source in the main scanning direction,
An A / D converter that converts the RGB analog signals into corresponding RGB digital signals;
A correction memory for temporarily holding the RGB digital signals and adjusting the output timing of the RGB digital signals;
A memory controller that controls writing of the RGB digital signals to the correction memory and reading of the RGB digital signals from the correction memory;
The memory controller is configured to write the RGB digital signals at the same pixel position on the same line at the same pixel positions on the lines that are separated from each other by the predetermined line interval so as to write the RGB digital signals at the same pixel position on successive memory addresses. A color image reading apparatus for controlling an image memory. For the RGB digital signal at the same pixel position on the same line output from the A / D converter at a timing shifted by a time corresponding to the predetermined line interval , first , the memory controller The color signal from which the first effective digital signal is obtained is written in the correction memory, and the color signal from which the second and third valid digital signals in the RGB digital signal are obtained from the correction memory. Write to the address that skips the address for
Next, after writing the color signal for obtaining the first effective signal for the predetermined line, the color signal for obtaining the second effective signal is written for the color signal for obtaining the first effective signal. Write to the address next to the address,
Further, after writing the color signal for obtaining the second effective signal for the predetermined line, the color signal for obtaining the third effective signal is used as the second color signal to be obtained. 2. The correction memory is controlled to write RGB digital signals at the same pixel position on the same line to successive memory addresses by writing to the address adjacent to the written address. Color image reader. In a color image reading apparatus for outputting an RGB digital signal corresponding to an original image read by a three-line image sensor having a line gap of a predetermined line interval by correcting the line gap using a correction memory, the RGB image signal is output. A memory controller for controlling writing of the digital signal to the correction memory and reading of the RGB digital signal from the correction memory;
The correction memory is controlled so as to write RGB digital signals at the same pixel position on the same line in consecutive lines supplied to the consecutive memory addresses for the simultaneously supplied RGB digital signals at the same pixel position on the lines separated by the predetermined line interval. A memory controller characterized by that.   The RGB digital signal is received at a timing shifted by a time corresponding to the predetermined line,
  First, among the RGB digital signals, the color signal from which the first effective digital signal is obtained is converted into the second and third effective digital signals of the RGB digital signal in the correction memory. Write to the address that skips the address for writing the signal of the color from which the signal is obtained,
  Next, after writing the color signal for obtaining the first effective signal for the predetermined line, the color signal for obtaining the second effective signal is written for the color signal for obtaining the first effective signal. Write to the address next to the address,
  Further, after writing the color signal for obtaining the second effective signal for the predetermined line, the color signal for obtaining the third effective signal is used as the second color signal to be obtained. 4. The correction memory is controlled so as to write RGB digital signals at the same pixel position on the same line to successive memory addresses by writing to the address adjacent to the address where the data is written. Memory controller.

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