JP2002354198A - Amplifier gain adjustment method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for adjusting each gain of amplifiers prepared corresponding to a plurality of sensor arrays each comprising line image sensors and also prepared for the purpose of amplifying each output signal of each sensor array in a short time. SOLUTION: When an adjustment pixel value of each sensor array is acquired, the sensor arrays are sequentially selected, whether or not gain adjustment of the amplifier of the selected sensor array is finished is discriminated according to the acquired adjustment pixel value, and a new amplifier gain is decided for the sensor arrays whose adjustment is not completed. Whether or not the amplifier gain adjustment of all the sensor arrays is finished is discriminated, and when not finished, after totally adjusting the amplifier gain according to the decided amplifier gain, the acquisition of a new adjustment pixel value is instructed repetitively to adjust the gain of the amplifier prepared in cross-reference with the sensor array.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amplifier which is prepared in association with a plurality of sensor arrays constituted by one or a plurality of line image sensors and is provided for amplifying output signals of the sensor arrays. More particularly, the present invention relates to an amplifier gain adjustment method for adjusting the gain of an amplifier in a short time.

In a color document reading apparatus, a color document is read using a line image sensor having an RGB sensor array. In such a color document reading apparatus, it is necessary to adjust the gain and offset (offset / gain) of an amplifier that amplifies the output signal of the line image sensor prepared in association with each of RGB. Must be implemented in the shortest possible time.

[0003]

2. Description of the Related Art FIG. 7 shows the structure of a color original reading apparatus to which the present invention is applied.

The color original reading apparatus shown in FIG. 1 has a pick roller 6 for picking color originals stacked on an original loading table 5 one by one, and a discharge for discharging the picked color originals to an original discharge table 7. With the color original conveyed by the rollers 8 as a reading target, a front-side line image sensor 1a for reading the front side of the conveyed color original, a back-side line image sensor 1b for reading the back side of the conveyed color original, and a color original The front lamp 2a illuminates the front surface of the original, the back lamp 2b illuminates the back surface of the color document, the front mirror 3a that bends the light path to the front line image sensor 1a, and the light path to the back line image sensor 1b. A back surface mirror 3b for bending the
By providing the front white reference sheet 4a prepared for shading correction and the back white reference sheet 4b prepared for shading correction, double-sided reading of a color document is performed.

[0005] Here, reference numeral 9 in the figure denotes a carrier, which is a line image sensor 1a for the surface / a lamp 2 for the surface.
a / the front side mirror 3a / the front side white reference sheet 4a is mounted and moved by the motor 10, so that the original table 1
A device capable of reading a document placed on the device 1;
Is a carrier home position sensor for setting the carrier 9 at its home position, and 13 is a control board on which a circuit as shown in FIG. 8 is mounted.

As shown in FIG. 8, an A / D converter 20 for amplifying and A / D converting image data output from the line image sensor 1 and an output of the A / D converter 20 are provided on the control board 13. An image control LSI 21 that performs image processing such as shading correction by inputting image data to be input, a white / black storage memory 22 that stores white reference data and black reference data required for shading correction, and an image control LS
A memory 23 for storing image data output by I21,
An interface LSI 24 for outputting image data stored in the memory 23 to the outside, a motor driver 25 for controlling the movement of the carrier 9 by controlling the motor 10,
An EPROM 26 for storing information such as a reading start position;
A CPU 27 and a power supply 28 are provided.

The surface line image sensor 1a
The sensor array for R is R0, the sensor array for G is G0,
If the sensor array for B is represented by B0, the sensor array for R of the back side line image sensor 1b is represented by R1, the sensor array for G is represented by G1, and the sensor array for B is represented by B1, As shown in FIG. 9, six amplifiers 30-i (i = 1) amplify the output signals of the paired sensor arrays.
To 6: an amplifier part of the A / D converter 20) and six A / D converters for A / D converting the output signals of the paired amplifiers 30-i.
D converter 31-i (i = 1 to 6: A / D conversion part of A / D converter 20) and one of the output signals of A / D converter 31-i are selected. A selector 32 and a sampling register 33 for sampling a pixel value selected and output by the selector 32 (may be a pixel value of a specific pixel or an average value of pixel values of some pixels)
And a memory 34 for storing gain values (gain and offset / gain values) of the six amplifiers 30-i.

In the color document reading apparatus thus constructed, the program running on the CPU 27 moves the carrier 9 to the black level gain adjustment position and turns off the lamps 2a and 2b as shown in FIG. Then, the front line image sensor 1a and the back line image sensor 1b
Are scanned at the same timing, and the offset signal is set so that the output signal of each amplifier 30-i becomes the specified output level.
Along with adjusting the gain, the carrier 9 is moved to the position of the front white reference sheet 4a, which is the gain adjustment position of the white level, and the lamps 2a and 2b are turned on, so that the front line image sensor 1a and the back line image are turned on. While scanning with the sensor 1b at the same timing, the white reference sheets 4a, 4a
A process is performed to adjust the gain so that the output signal of each amplifier 30-i that reads b becomes a specified output level.

FIGS. 11 to 14 show a prior art of the gain adjustment processing.

That is, in the prior art, when adjusting the gain of the amplifier 30-i, first, as shown in the processing flow of FIGS.
The carrier 9 is moved to the position of the front white reference sheet 4a, which is the gain adjustment position of the white level.
The lamps 2a and 2b are turned on.

Subsequently, in step 3, all the gain values stored in the memory 34 are set to the minimum, and accordingly, the gains of all the amplifiers 30-i are set to the minimum. Subsequently, in step 4, the sensor array R0 (surface R
The selector 32 is controlled so that the pixel value output from the sensor array is input to the sampling register 33.

Subsequently, in step 5, the process waits for the scanning of one line of the line image sensors 1a and 1b to be completed. When the scanning of one line is completed, the process proceeds to step 6, where the scanning is terminated. In response, sampling register 3
3 is read. That is, as shown in FIG. 15, when the scanning of one line of the line image sensors 1a and 1b ends, the output of the sensor array R0 is held in the sampling register 33 in response to the end of the scanning. Read it.

Subsequently, in step 7, it is determined whether or not the output of the read sensor array R0 has reached the specified level. If it is determined that the output has not reached the specified level, the process proceeds to step 8, The gain value of the sensor array R0 stored in the memory 34 is incremented by one unit, and in the subsequent step 9, the gain value of the sensor array R0 stored in the incremented memory 34 is changed to the sensor array R
After setting to the amplifier 30-1 of 0, the process returns to step 5.

By repeating the processing of steps 5 to 9 in this way, if it is determined in step 7 that the output of the sensor array R0 has reached the specified level, the process proceeds to step 10 and proceeds to step 10. The selector 32 is controlled so that the pixel value output from G0 (sensor array for the surface G) is input to the sampling register 33. That is, when it is determined that the adjustment of the amplifier 30-1 of the sensor array R0 has been completed, the selector 32 is controlled so that the pixel value output from the sensor array G0 is input to the sampling register 33.

Subsequently, in step 11, the scanning of one line by the line image sensors 1a and 1b is waited for, and when the scanning of one line is completed, the process proceeds to step 12, where the scanning is terminated. In response, the output of the sensor array G0 to be held in the sampling register 33 is read.

Subsequently, in step 13, it is determined whether or not the output of the read sensor array G0 has reached the specified level. When it is determined that the output has not reached the specified level, the routine proceeds to step 14, The gain value of the sensor array G0 stored in the memory 34 is incremented by one unit, and in a succeeding step 15, the gain value of the sensor array G0 stored in the incremented memory 34 is set in the amplifier 30-2 of the sensor array G0. Then, the process returns to step 11.

By repeating the processing of steps 11 to 15 in this way, step 13
When it is determined that the output of the sensor array G0 reaches the specified level, the process proceeds to step 16, where the sensor array B0
The selector 32 is controlled so that the pixel value output from the (sensor array for the surface B) is input to the sampling register 33. That is, when it is determined that the adjustment of the amplifier 30-2 of the sensor array G0 has been completed, the selector 32 is controlled so that the pixel value output from the sensor array B0 is input to the sampling register 33.

Subsequently, in step 17, the scanning of one line of the line image sensors 1a and 1b is waited for, and when the scanning of one line is completed, the process proceeds to step 18, where the scanning is terminated. In response, the output of the sensor array B0 to be held in the sampling register 33 is read.

Subsequently, in step 19, it is determined whether or not the output of the read sensor array B0 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 20, The gain value of the sensor array B0 stored in the memory 34 is incremented by one unit, and in the following step 21, the gain value of the sensor array B0 stored in the incremented memory 34 is set in the amplifier 30-3 of the sensor array B0. Then, the process returns to step 17.

By repeating the processing of steps 17 to 21 in this manner, step 19
When it is determined that the output of the sensor array B0 reaches the specified level, the process proceeds to step 22, where the sensor array R1
The selector 32 is controlled so that the pixel value output from the (back side R sensor array) is input to the sampling register 33. That is, when it is determined that the adjustment of the amplifier 30-3 of the sensor array B0 has been completed, the selector 32 is controlled so that the pixel value output from the sensor array R1 is input to the sampling register 33.

Subsequently, in step 23, the scanning of one line of the line image sensors 1a and 1b is waited for, and when the scanning of one line is completed, the process proceeds to step 24, where the scanning is terminated. In response, the output of the sensor array R1 to be held in the sampling register 33 is read.

Subsequently, in step 25, it is determined whether or not the output of the read sensor array R1 has reached a specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 26. The gain value of the sensor array R1 stored in the memory 34 is incremented by one unit, and in the following step 27, the gain value of the sensor array R1 stored in the incremented memory 34 is set in the amplifier 30-4 of the sensor array R1. Then, the process returns to step 23.

In this way, by repeating the processing of steps 23 to 27, step 25
When it is determined that the output of the sensor array R1 reaches the specified level, the process proceeds to step 28, where the sensor array G1
The selector 32 is controlled so that the pixel value output from the (back side G sensor array) is input to the sampling register 33. That is, when it is determined that the adjustment of the amplifier 30-4 of the sensor array R1 has been completed, the selector 32 is controlled so that the pixel value output from the sensor array G1 is input to the sampling register 33.

Subsequently, in step 29, the process waits for the scanning of one line of the line image sensors 1a and 1b to be completed. When the scanning of one line is completed, the process proceeds to step 30, where the scanning is terminated. In response, the output of the sensor array G1 to be held in the sampling register 33 is read.

Subsequently, in step 31, it is determined whether or not the output of the read sensor array G1 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 32. The gain value of the sensor array G1 stored in the memory 34 is incremented by one unit, and in a subsequent step 33, the gain value of the sensor array G1 stored in the incremented memory 34 is set in the amplifier 30-5 of the sensor array G1. Then, the process returns to step 29.

By repeating the processing of steps 29 to 33 in this way, step 31
When it is determined that the output of the sensor array G1 has reached the specified level, the routine proceeds to step 34, where the sensor array B1
The selector 32 is controlled so that the pixel value output from the (back side B sensor array) is input to the sampling register 33. That is, when it is determined that the adjustment of the amplifier 30-5 of the sensor array G1 has been completed, the selector 32 is controlled so that the pixel value output from the sensor array B1 is input to the sampling register 33.

Subsequently, in step 35, the process waits for the scanning of one line of the line image sensors 1a and 1b to be completed. When the scanning of one line is completed, the process proceeds to step 36, where the scanning is terminated. In response, the output of the sensor array B1 to be held in the sampling register 33 is read.

Subsequently, in step 37, it is determined whether or not the output of the read sensor array B1 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 38. The gain value of the sensor array B1 stored in the memory 34 is incremented by one unit, and in a succeeding step 39, the gain value of the sensor array B1 stored in the incremented memory 34 is set in the amplifier 30-6 of the sensor array B1. Then, the process returns to step 35.

Then, steps 35 to 39
When it is determined in step 37 that the output of the sensor array B1 has reached the specified level in step 37, it is determined that the adjustment of the amplifier 30-6 of the sensor array B1 has been completed, and the process is terminated. finish.

As described above, in the prior art, first of all,
Amplifier 30 of sensor array R0 (sensor array for surface R)
Adjust the gain of -1 and when the adjustment is complete,
Amplifier 30 of sensor array G0 (sensor array for surface G)
Adjust the gain of -2, and when the adjustment is complete,
Amplifier 30 of sensor array B0 (sensor array for surface B)
Adjust the gain of -3, and when the adjustment is complete,
Amplifier 30 of sensor array R1 (sensor array for back surface R)
Adjust the gain of -4, and when that adjustment is complete,
Amplifier 30 of sensor array G1 (sensor array for backside G)
Adjust the gain of -5, and when that adjustment is complete,
Amplifier 30 of sensor array B1 (sensor array for back surface B)
In other words, the processing is performed such that the gain of the amplifier 30-i of each sensor array is adjusted in order, such as adjusting the gain of -6.

[0031]

However, according to such a conventional technique, the amplifier 3 of each sensor array is required.
Since the processing is performed so as to adjust the gains of 0-i in order, there is a problem that the adjustment takes time.

That is, in the case of a color original reading apparatus that performs double-sided reading of a color original, there are six sensor arrays, so that a color original reading apparatus that performs single-sided single-color reading with only one sensor array is used. On the other hand, there is a problem that it takes six times as long to adjust the gain of the amplifier 30-i.

The present invention has been made in view of such circumstances, and has been prepared in association with a plurality of sensor arrays constituted by one or more line image sensors.
It is an object of the present invention to provide a new amplifier gain adjustment method that can execute the adjustment in a short time when adjusting the gain of an amplifier prepared for amplifying the output signal of the sensor array.

[0034]

In order to achieve this object, according to the present invention, a plurality of sensor arrays constituted by one or a plurality of line image sensors are prepared in association with each other, and these sensor arrays are prepared. When adopting a configuration for adjusting the gain of an amplifier prepared for amplifying an output signal, a first process of acquiring a pixel value for adjustment of each sensor array, and a sensor array are sequentially selected and acquired. A second step of determining whether or not the adjustment of the amplifier gain has been completed according to the adjusted pixel value, and determining a new amplifier gain value for the sensor array for which adjustment has not been completed; Determine whether the adjustment of the amplifier gain has been completed, and if not, adjust the amplifier gain according to the determined amplifier gain value, and then obtain a new adjustment pixel value Configured to include a third step of instructing.

At the time of adopting this configuration, a flag prepared for the sensor array is prepared, and for the sensor array for which the adjustment of the amplifier gain has been completed, processing is performed so as to record the fact in the flag. There is.

By preparing this flag, it is possible to immediately determine whether or not the adjustment of the amplifier gain has been completed irrespective of the adjustment pixel value, and to adjust the amplifier gain for all sensor arrays. It will be possible to determine whether or not it has been completed.

In the present invention configured as described above, when the adjustment pixel values of each sensor array are obtained, the sensor arrays are sequentially selected, and the amplifiers of the selected sensor array are selected in accordance with the obtained adjustment pixel values. It is determined whether or not the gain adjustment has been completed, and a new amplifier gain value is determined for a sensor array for which adjustment has not been completed.

Then, it is determined whether or not the adjustment of the amplifier gain has been completed for all of the sensor arrays. If the adjustment has not been completed, the amplifier gain is collectively adjusted in accordance with the determined amplifier gain value, and then a new By repeatedly instructing the acquisition of the adjustment pixel value, the gain of the amplifier prepared in association with the sensor array is adjusted.

As described above, according to the present invention, an amplifier prepared in association with a plurality of sensor arrays constituted by one or a plurality of line image sensors and provided for amplifying output signals of those sensor arrays is provided. To adjust the gain of each amplifier during one scanning cycle (exposure cycle), and to judge that the adjustment has not been completed. Adopts a configuration in which a new amplifier gain value is determined and the amplifier gain is adjusted in accordance with the amplifier gain value determined in such a manner. By adjusting the gain, the gain of the amplifier can be adjusted in a short time.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail according to embodiments.

FIG. 1 shows an embodiment of the structure of a color document reading apparatus provided with the present invention. Here, in this embodiment, the same configuration as the device configuration shown in FIG. 7 is assumed.

As shown in this figure, a color document reading apparatus for performing double-side reading of a color document is provided with a sampling register 33-1 for sampling a pixel value output from the sensor array R0 when the present invention is provided. A sampling register 33-2 for sampling a pixel value output from the sensor array G0, a sampling register 33-3 for sampling a pixel value output from the sensor array B0, and a sampling register for sampling a pixel value output from the sensor array R1. 33-4, and a sampling register 33-5 for sampling a pixel value output from the sensor array G1.
And six sampling registers 33-i called sampling registers 33-6 for sampling the pixel values output from the sensor array B1, and the pixel values held by these sampling registers 33-i are directly input to the CPU 27. Configuration will be adopted.

Here, the pixel value sampled by the sampling register 33-i may be a pixel value of a specific pixel, or may be an average value of pixel values of several pixels.

Further, the memory 34 has six amplifiers 3
In addition to storing two types of gain values 0-i (gain and offset / gain values), six amplifiers 30-i used for gain adjustment processing and offset / gain adjustment processing
Is stored.

In the color document reading apparatus thus configured, the program running on the CPU 27 moves the carrier 9 to the black level gain adjustment position and turns off the lamps 2a and 2b as shown in FIG. Then, the front line image sensor 1a and the back line image sensor 1b
Are scanned at the same timing, and the offset signal is set so that the output signal of each amplifier 30-i becomes the specified output level.
In addition to adjusting the gain, the carrier 9 is moved to the position of the front white reference sheet 4a, which is the gain adjustment position of the white level, and the lamps 2a and 2b are turned on, so that the front line image sensor 1a and the back line image are formed. While scanning with the sensor 1b at the same timing, the white reference sheets 4a, 4a
A process is performed to adjust the gain so that the output signal of each amplifier 30-i that reads b becomes a specified output level.

FIGS. 2 to 5 show one embodiment of the processing flow of the gain adjustment processing executed according to the present invention.

That is, in the present invention, when adjusting the gain of the amplifier 30-i, as shown in the processing flow of FIGS. 2 to 5, first, in step 1, the carrier 9 is set to the white level. It moves to the position of the front white reference sheet 4a which is the gain adjustment position, and in the following step 2, the lamps 2a and 2b are turned on.

Subsequently, in step 3, "0" is set in the six flags stored in the memory 34, and in step 4, the six gain values stored in the memory 34 are set to the minimum value. Depending on all amplifiers 30-i
Set the gain of to the minimum.

Subsequently, in step 5, the scanning of one line by the line image sensors 1a and 1b is completed. When the scanning of one line is completed, the process proceeds to step 6 to correspond to the sensor array R0. Flag R0 prepared with
Is set to "0".

As will be understood from the description below, when the gain adjustment of the amplifier 30-1 prepared in association with the sensor array R0 is completed, "1" is set in the flag R0. By referring to the flag R0, it is determined whether or not the gain adjustment of the amplifier 30-1 has been completed.

By this determination processing, the flag R0 is set to "0".
Is determined, that is, when it is determined that the gain adjustment of the amplifier 30-1 prepared in association with the sensor array R0 has not been completed, the process proceeds to step 7, and the sensor array R0 The output of the sensor array R0 that is to be held in the sampling register 33-1 prepared in association with is read.

That is, the line image sensors 1a, 1
When the scanning of one line b is completed, the sampling register 33-1 stores the sensor array R0 in response to the completion of the scanning.
Because the output of is retained, it is read.

Subsequently, in step 8, it is determined whether or not the output of the read sensor array R0 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 9, The gain value of the sensor array R0 stored in the memory 34 is incremented by one unit.

On the other hand, if it is determined in step 8 that the output of the read sensor array R0 has reached the specified level, the processing in step 1 is skipped without performing the processing in step 9.
By proceeding to 0 and setting “1” to the flag R0,
The fact that the gain adjustment of the amplifier 30-1 prepared in association with the sensor array R0 is completed is recorded.

Then, in step 6, when it is determined that "0" is not set in the flag R0, that is, when it is determined that "1" is set in the flag R0, the process up to the previous time is performed. It is determined that the gain adjustment of the amplifier 30-1 prepared in association with the sensor array R0 has been completed, and the processing of Steps 7 to 10 is omitted.

Subsequently, at step 11, the sensor array G0
It is determined whether or not “0” is set in the flag G0 prepared in association with.

As will be understood from the later description, when the gain adjustment of the amplifier 30-2 prepared in association with the sensor array G0 is completed, "1" is set to the flag G0. By referring to this flag G0, it is determined whether or not the gain adjustment of the amplifier 30-2 has been completed.

By this determination processing, the flag G0 is set to "0".
Is set, that is, when it is determined that the gain adjustment of the amplifier 30-2 prepared in association with the sensor array G0 has not been completed, the process proceeds to step 12, where the sensor array G0 The output of the sensor array G0, which is to be held in the sampling register 33-2 prepared in association with.

That is, the line image sensors 1a, 1
When the scanning for one line of b is completed, the sampling register 33-2 stores the sensor array G0 in response to the completion of the scanning.
Because the output of is retained, it is read.

Subsequently, in step 13, it is determined whether or not the output of the read sensor array G0 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 14, The gain value of the sensor array G0 stored in the memory 34 is incremented by one unit.

On the other hand, when it is determined in step 13 that the output of the read sensor array G0 has reached the specified level, the process proceeds to step 15 without performing the processing in step 14, and "1" is set in the flag G0. By setting, the amplifier 30 prepared in association with the sensor array G0
Record that the -2 gain adjustment is completed.

Then, in step 11, when it is determined that "0" is not set in the flag G0, that is, when it is determined that "1" is set in the flag G0, the process up to the previous time is performed. It is determined that the gain adjustment of the amplifier 30-2 prepared in association with the sensor array G0 has been completed, and the processing of steps 12 to 15 is omitted.

Subsequently, at step 16, the sensor array B0
It is determined whether or not “0” is set in the flag B0 prepared in association with.

As will be understood from the later description, when the gain adjustment of the amplifier 30-3 prepared in association with the sensor array B0 is completed, "1" is set in the flag B0. By referring to the flag B0, it is determined whether or not the gain adjustment of the amplifier 30-3 has been completed.

By this determination processing, the flag B0 is set to "0".
Is determined, that is, when it is determined that the gain adjustment of the amplifier 30-3 prepared in association with the sensor array B0 has not been completed, the process proceeds to step 17, where the sensor array B0 The output of the sensor array B0, which is to be held in the sampling register 33-3 prepared in association with.

That is, the line image sensors 1a, 1
When the scanning of one line b is completed, the sampling register 33-3 stores the sensor array B0 in response to the completion of the scanning.
Because the output of is retained, it is read.

Subsequently, in step 18, it is determined whether or not the output of the read sensor array B0 has reached the specified level. If it is determined that the output has not reached the specified level, the process proceeds to step 19, The gain value of the sensor array B0 stored in the memory 34 is incremented by one unit.

On the other hand, when it is determined in step 18 that the output of the read sensor array B0 has reached the specified level, the process proceeds to step 20 without performing the processing in step 19, and "1" is set in the flag B0. By setting, the amplifier 30 prepared in association with the sensor array B0
Record that the gain adjustment of -3 is completed.

When it is determined in step 16 that "0" has not been set in the flag B0, that is, when it is determined that "1" has been set in the flag B0, according to the processing up to the previous time, It is determined that the gain adjustment of the amplifier 30-3 prepared in association with the sensor array B0 has been completed, and the processing of steps 17 to 20 is omitted.

Subsequently, at step 21, the sensor array R1
It is determined whether or not “0” is set in the flag R1 prepared in association with.

As will be understood from the description below, when the gain adjustment of the amplifier 30-4 prepared in association with the sensor array R1 is completed, "1" is set to the flag R1. By referring to the flag R1, it is determined whether or not the gain adjustment of the amplifier 30-4 has been completed.

By this determination processing, the flag R1 is set to "0".
When it is determined that is set, that is, when it is determined that the gain adjustment of the amplifier 30-4 prepared in association with the sensor array R1 has not been completed, the routine proceeds to step 22, where the sensor array R1 The output of the sensor array R1 that is to be held in the sampling register 33-4 prepared in association with is read.

That is, the line image sensors 1a, 1
When the scanning of one line b is completed, the sampling register 33-4 stores the sensor array R1 in response to the completion of the scanning.
Because the output of is retained, it is read.

Subsequently, in step 23, it is determined whether or not the output of the read sensor array R1 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 24. The gain value of the sensor array R1 stored in the memory 34 is incremented by one unit.

On the other hand, when it is determined in step 23 that the output of the read sensor array R1 has reached the specified level, the process proceeds to step 25 without performing the process in step 24, and "1" is set in the flag R1. By setting, the amplifier 30 prepared in association with the sensor array R1
Record that the gain adjustment of -4 is completed.

When it is determined in step 21 that the flag R1 is not set to "0", that is, when it is determined that the flag R1 is set to "1", according to the processing up to the previous time, It is determined that the gain adjustment of the amplifier 30-4 prepared in association with the sensor array R1 has been completed, and the processing of steps 22 to 25 is omitted.

Subsequently, at step 26, the sensor array G1
It is determined whether or not “0” is set in the flag G1 prepared in association with.

As will be understood from the later description, when the gain adjustment of the amplifier 30-5 prepared in association with the sensor array G1 is completed, "1" is set to the flag G1. By referring to the flag G1, it is determined whether or not the gain adjustment of the amplifier 30-5 has been completed.

By this determination processing, the flag G1 is set to "0".
Is determined, that is, when it is determined that the gain adjustment of the amplifier 30-5 prepared in association with the sensor array G1 is not completed, the process proceeds to step 27, and the sensor array G1 The output of the sensor array G1 that is to be held in the sampling register 33-5 prepared in association with is read.

That is, the line image sensors 1a, 1
When the scanning of one line b is completed, the sampling register 33-5 stores the sensor array G1 in response to the completion of the scanning.
Because the output of is retained, it is read.

Subsequently, at step 28, it is determined whether or not the output of the read sensor array G1 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 29, The gain value of the sensor array G1 stored in the memory 34 is incremented by one unit.

On the other hand, when it is determined in step 28 that the output of the read sensor array G1 has reached the specified level, the process proceeds to step 30 without performing the process in step 29, and "1" is set in the flag G1. By setting, the amplifier 30 prepared in association with the sensor array G1 is set.
Record that the gain adjustment of -5 is completed.

When it is determined in step 26 that "0" is not set in the flag G1, that is, when it is determined that "1" is set in the flag G1, the processing according to the previous processing is performed. It is determined that the gain adjustment of the amplifier 30-5 prepared in association with the sensor array G1 has been completed, and the processing of steps 27 to 30 is omitted.

Subsequently, at step 31, the sensor array B1
It is determined whether or not “0” is set in the flag B1 prepared in association with.

As will be understood from the later description, when the gain adjustment of the amplifier 30-6 prepared in association with the sensor array B1 is completed, "1" is set to the flag B1. By referring to the flag B1, it is determined whether or not the gain adjustment of the amplifier 30-6 has been completed.

By this determination processing, the flag B1 is set to "0".
When it is determined that is set, that is, when it is determined that the gain adjustment of the amplifier 30-6 prepared in association with the sensor array B1 is not completed, the process proceeds to step 32, where the sensor array B1 is set. The output of the sensor array B1 that is to be held in the sampling register 33-6 prepared in association with is read.

That is, the line image sensors 1a, 1
When the scanning of one line b is completed, the sampling register 33-6 stores the sensor array B1 in response to the completion of the scanning.
Because the output of is retained, it is read.

Subsequently, in step 33, it is determined whether or not the output of the read sensor array B1 has reached the specified level. When it is determined that the output has not reached the specified level, the process proceeds to step 34. The gain value of the sensor array B1 stored in the memory 34 is incremented by one unit.

On the other hand, when it is determined in step 33 that the output of the read sensor array B1 has reached the specified level, the process proceeds to step 35 without performing the process in step 34, and "1" is set in the flag B1. By setting, the amplifier 30 prepared in association with the sensor array B1
Record that the gain adjustment of -6 is completed.

When it is determined at step 31 that "0" has not been set to the flag B1, that is, when it is determined that "1" has been set to the flag B1, the process up to the previous time is performed. It is determined that the gain adjustment of the amplifier 30-6 prepared in association with the sensor array B1 has been completed, and the processing of steps 32 to 35 is omitted.

Subsequently, in step 36, the six flags R0, G0, B0, R1, G1,
It is determined whether or not all “1” s have been set in B1.
When it is determined that "1" is not set in all the flags, the process proceeds to step 37, in which the gain value stored in the memory 34 is set in the corresponding amplifier 30-i, thereby setting the gain of the amplifier 30-i. After adjusting the gain, the process returns to step 5.

On the other hand, at step 36, the six flags R0, G0, B0, R1, G1, B stored in the memory 34
When it is determined that all "1" s have been set to 1, it is determined that the gain adjustment of the amplifier 30-i has been completed, and the process ends.

As described above, in the present invention, as shown in FIG. 6, processing is performed so as to adjust the gains of the six amplifiers 30-i in parallel.

In the processing flow shown in FIGS. 2 to 5, the gain adjustment processing of the amplifier 30-i has been described. However, the offset / gain adjustment processing of the amplifier 30-i is adjusted in parallel according to the same processing. Will be processed.

In the embodiment described above, when the flag is set to "0", processing is performed so that the output of the corresponding sensor array to be held in the sampling register 33-i is read. However, it is also possible to read the output of the sensor array unconditionally and then determine whether or not the flag is set to “0”. When the former processing configuration is adopted, unnecessary reading is not performed, so that the processing can be speeded up.

In the embodiment described above, the gain value of the amplifier 30-i is processed so as to be incremented by one unit from the minimum value, but is decremented by one unit from the maximum value. It may be processed in any way.

[0097]

As described above, according to the present invention, a plurality of sensor arrays each including one or a plurality of line image sensors are prepared in association with each other and used for amplifying output signals of the sensor arrays. When adjusting the gain of the prepared amplifier, it is necessary to determine whether the adjustment of the gain value of each amplifier has been completed in one scanning cycle, and to determine that the adjustment has not been completed. Adopts a configuration in which a new amplifier gain value is determined and the amplifier gain is adjusted in accordance with the amplifier gain value determined in such a manner. By adjusting the gain, the gain of the amplifier can be adjusted in a short time.

[Brief description of the drawings]

FIG. 1 is an embodiment of an apparatus configuration of a color document reading apparatus having the present invention.

FIG. 2 is an embodiment of a processing flow executed by a color document reading apparatus having the present invention.

FIG. 3 is an embodiment of a processing flow executed by a color document reading apparatus having the present invention.

FIG. 4 is an embodiment of a processing flow executed by a color document reading apparatus having the present invention.

FIG. 5 is an embodiment of a processing flow executed by a color document reading apparatus having the present invention.

FIG. 6 is an explanatory diagram of a process executed by the color document reading apparatus having the present invention.

FIG. 7 is an explanatory diagram of an apparatus configuration of a color original reading apparatus to which the present invention is applied.

FIG. 8 is an explanatory diagram of an apparatus configuration of a color original reading apparatus to which the present invention is applied.

FIG. 9 is an explanatory diagram of an apparatus configuration of a color original reading apparatus to which the present invention is applied.

FIG. 10 is a processing flow of gain adjustment processing executed by the color document reading apparatus to which the present invention is applied.

FIG. 11 is a processing flow of a conventional technique.

FIG. 12 is a processing flow of a conventional technique.

FIG. 13 is a processing flow of a conventional technique.

FIG. 14 is a processing flow of a conventional technique.

FIG. 15 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 1a Front-side line image sensor 1b Back-side line image sensor 2a Front-side lamp 2b Back-side lamp 3a Front-side mirror 3b Back-side mirror 4a Front-side white reference sheet 4b Back-side white reference sheet 5 Document loading table 6 Pick roller 7 Original discharge Table 8 Discharge roller 9 Carrier 10 Motor 11 Document table 12 Carrier home position sensor 13 Control board 27 CPU 30 Amplifier 31 A / D converter 33 Sampling register 34 Memory

Claims (4)

[Claims] 1. An amplifier gain that is prepared in association with a plurality of sensor arrays constituted by one or a plurality of line image sensors and adjusts the gain of an amplifier prepared for amplifying an output signal of the sensor array. An adjustment method, comprising: a first step of acquiring an adjustment pixel value of each sensor array; and selecting a sensor array in order and determining whether or not the adjustment of the amplifier gain is completed according to the acquired adjustment pixel value. Judging and determining a new amplifier gain value for the sensor array for which adjustment has not been completed, and determining whether the amplifier gain adjustment has been completed for all sensor arrays. And a third step of adjusting the amplifier gain according to the amplifier gain value and instructing the acquisition of a new adjustment pixel value if not. Loop gain adjustment method. 2. The amplifier gain adjustment method according to claim 1, wherein, in the second step, for a sensor array for which the amplifier gain adjustment has been completed, the fact is recorded in a flag prepared for the sensor array. Thus, it is determined whether or not the adjustment of the amplifier gain has been completed by referring to the flag from the next cycle. In the third step, by referring to the flag, the amplifier gain can be adjusted for all sensor arrays. A method for adjusting an amplifier gain, comprising: determining whether adjustment has been completed. 3. The amplifier gain adjustment method according to claim 2, wherein in the first step, the adjustment pixel value is not acquired for a sensor array for which the adjustment of the amplifier gain specified by the flag has been completed. A method for adjusting an amplifier gain. 4. The amplifier gain adjustment method according to claim 1, wherein in the second step, the new amplifier gain value is increased or decreased by one unit at a time. Determining an amplifier gain adjustment method.