JP3469317B2 - Image processing device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image processing apparatus such as a digital monochrome copying machine, a digital color copying machine, a color facsimile, a printer having a .gamma.

[0002]

2. Description of the Related Art Conventionally, an image processing unit for performing a predetermined image processing on an input signal, an output device for outputting an image by an output signal of the image processing unit, a writing value of the image processing unit and the output device. In an image processing apparatus such as a digital monochrome copying machine, a digital color copying machine, a color facsimile, and a printer having a γ correction unit for correcting the γ characteristic with the output image of “color image scanner design technology”, Trikeps, WHITE SERIES N
o. 130, pages 123 to 126, the output γ characteristic differs depending on the element and is not completely linear, and the γ correction value is given from the outside. In addition, the same “Color Image Scanner Design Technology”, Trikeps, WH
ITE SERIES No. 130, 157-15
As described on page 8, the output γ characteristic is not linear due to the relationship between the writing pitch and the dot system. Further, as described in "Various Problems of Latent Image Formation and Analytical Method", Electrophotographic Society Journal, Vol. 26, No. 1 (1987), charging and exposure of a photoconductor used in a process of an output device. The characteristics relating to fluctuate due to various factors, such as electrostatic fatigue and wear of the photoconductor drum, exposure fatigue, temperature and humidity. Therefore, the output γ characteristic changes.

FIG. 14 shows an example of the structure of a printer. An input signal of the printer is γ-corrected by a γ-correction unit 11 and is dithered by an image processing unit 12 including a dither processing unit, and then sent to an output device 13. The output device 13 receives an image from the input signal from the image processing unit 12. Is output. The γ characteristic of the printer differs for each characteristic of the output device 13 as described above.
For this reason, the γ correction unit 11 must externally select the optimum γ correction curve according to the characteristics of the output device 13 from the plurality of γ correction curves as shown in FIG. 15 by the γ correction curve selection value as described above. I have to. The γ correction unit 11 adopts a Look Up Table method (hereinafter referred to as LUT) using a memory 14 such as a ROM as shown in FIG. 16, for example, and selects an optimum γ correction curve from the outside according to a γ correction curve selection value. To do.

[0004]

In the image processing apparatus such as the printer described above, the γ correction section selects the optimum γ correction curve from the outside according to the γ correction curve selection value.
It took a long time to select the optimum γ correction curve from the correction curves.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image processing apparatus which solves the above problems and which can select a γ correction curve at high speed and with high accuracy.

[0006]

In order to achieve the above object, the invention according to claim 1 provides a predetermined image for an input signal.
An image processing unit that performs image processing and an output signal of this image processing unit
And an output device for outputting an image by the
Corrects the γ characteristic between the imprint value and the output image of the output device.
In the image processing apparatus having a γ correction unit for
Input signal to the image processing unit to the output device.
A patch generation unit for outputting a patch and the output device.
The patch reading section that reads the patch output from the
Γ characteristic is obtained from the output signal of the patch reading unit of
And the γ characteristic from this γ characteristic determination section
Generate a target γ correction curve from the previously set target γ characteristics
γ correction curve determination unit and γ of a plurality of given density regions
Compensation curve is synthesized by a predetermined calculation and synthesized γ correction car
Γ-correction curve synthesizing section
The combined γ correction curve from the control unit and the γ correction curve determination unit
Deviation from the target γ correction curve
The target deviation and the combined γ correction curve that is larger than the
The second deviation where the combined γ correction curve is smaller than the γ correction curve
And is calculated for each density area, and the first deviation is calculated for each density area.
The maximum deviation is the deviation that is larger between
From the difference value determination unit and the output signal of this deviation value determination unit,
Concerning the concentration range where the maximum deviation is maximum in the concentration range
When the first deviation is larger than the positive deviation threshold of the density region,
The γ correction amount of the γ correction curve in the density region is reduced by m steps
The γ-correction curve selection value manipulated variable
The first deviation is larger than the positive deviation threshold of the density area
And the second deviation is larger than the negative deviation threshold of the density region.
Sometimes the γ correction amount of the γ correction curve in the density area is n steps larger.
To determine the selected value operation amount of the γ correction curve so that
Correction curve selection value manipulated variable determiner and this γ correction curve selection
Of the γ correction curve for each density area from the selected value manipulated variable determiner
Gamma correction curves for multiple density areas based on the selected value operation amount
Is selected and given to the γ correction curve synthesizing unit.
And the first and second deviations of all density areas
Is within the threshold of each density region, the
Means for correcting the γ characteristic by a combined γ correction curve,
It is equipped with .

According to a second aspect of the present invention, an input signal is applied.
An image processing unit that performs predetermined image processing, and the image processing unit
An output device for outputting an image according to an output signal;
Γ characteristic of the written value of the processing unit and the output image of the output device
In an image processing apparatus having a γ correction unit for correcting
Input the patch signal to the image processing unit and output it.
Output unit for outputting a patch to the input device, and the output
Patch reading to read the patch output by the device
Section and the output signal of this patch reading section to obtain the γ characteristic.
And the γ characteristic from this γ characteristic determining section
Create a target γ correction curve from the target γ characteristics created in advance.
Γ correction curve determiner to generate, and a plurality of given concentrations
The γ correction curve of the area is synthesized by a predetermined calculation and synthesized γ
The γ-correction curve synthesizing unit to be the correction curve and this γ-correction curve
Combined γ correction curve from the curve combiner and the γ correction curve
The deviation from the target γ correction curve from the decision unit
The first deviation in which the combined γ correction curve is larger than the γ correction curve
And the combined γ correction curve is smaller than the target γ correction curve.
The deviation of 2 is calculated for each density area and the
The larger of the deviation of 1 and the deviation of 2 is the maximum deviation.
And the output signal of this deviation value determination unit.
Concentration range with the largest maximum deviation among multiple concentration ranges
For the first deviation is greater than the second deviation for
When the difference is larger than the positive deviation threshold of the density area, the density
If the γ correction amount of the γ correction curve of the area is not the minimum, the density
Reduce the amount of γ correction of the γ correction curve in the area by m steps
The selected value operation amount of the γ correction curve is determined, and γ of the density region is determined.
If the γ correction amount of the correction curve is the minimum, it is adjacent to the density area
The γ correction amount of the γ correction curve in the
Select the γ correction curve selection value operation amount so that
Concerning the concentration range where the maximum deviation is maximum in the concentration range
If the first deviation is not greater than the second deviation and the second deviation is
When the density deviation is larger than the negative deviation threshold value of the density area, the density area
If the γ correction amount of the
Γ correction curve so that the γ correction amount of the
Determines the manipulated variable for the selected value of the positive curve and corrects the γ in the density area.
If the γ correction amount of the curve is maximum, it is adjacent to the density area
The γ correction amount of the γ correction curve in the density region will increase by n steps.
Gamma correction car that determines the manipulated variable of the gamma correction curve
And the γ correction curve selection value operation
Select value of γ correction curve for each density area from quantity determination unit
Select gamma correction curves for multiple density areas based on
And a γ correction curve selecting section to be given to the γ correction curve synthesizing section.
And the first and second deviations of all density areas are
When it is within the threshold value of the area,
A means for correcting the γ characteristic by a positive curve is provided .

The invention according to claim 3 is the invention according to claim 1 or 2.
In the image processing device described above, the γ correction curve selection value
Of the γ-correction curve for each density area determined by the manipulated variable determiner
Operate the selected value operation amount back and forth in P steps to obtain multiple concentration ranges.
Equipped with a means to select the γ correction curve that minimizes the deviation of the range
It is a gift .

[0009]

[0010]

[0011]

According to the invention of claim 1, the patch generator
The patch signal is input to the image processing unit and the output device
The patch output by this output device.
Read by the touch reading unit. The γ characteristic determination unit
The γ characteristic is calculated from the output signal of the
The curve determination unit creates in advance the γ characteristic from the γ characteristic determination unit.
A target γ correction curve is generated from the set target γ characteristic. γ
The correction curve synthesis unit is given by the γ correction curve selection unit.
The γ correction curves for multiple density areas are combined by a predetermined calculation.
To form a combined γ correction curve. The deviation value determination unit
Positive γ correction curve and γ correction curve from the positive curve synthesizing section
The deviation from the target γ correction curve from the decision unit
The first deviation in which the combined γ correction curve is larger than the γ correction curve
And the combined γ correction curve is smaller than the target γ correction curve.
The deviation of 2 is calculated for each density area and the
The larger of the deviation of 1 and the deviation of 2 is the maximum deviation.
And The γ correction curve selection value manipulated variable determiner determines the deviation value
The maximum deviation from the output signal of the constant section
For a density area that is large, the first deviation is
If it is larger than the deviation threshold,
Selected value of γ correction curve so that the γ correction amount is reduced by m steps
The manipulated variable is determined, and the first deviation is
If the second deviation is larger than the positive deviation threshold value of the
When it is larger than the negative deviation threshold of the
Of the γ correction curve so that the
Determine the manipulated variable for the selected value. γ correction curve selector is γ correction
Γ correction for each density area from the curve selection value manipulated variable determiner
Based on the curve manipulated variable selection value,
Select a positive curve and give it to the γ-correction curve synthesizer.
The first deviation and the second deviation of the density area are the threshold values of each density area.
The γ correction unit uses the combined γ correction curve to
Correct the sex.

According to the second aspect of the invention, the patch generation unit
These patch signals are input to the image processing unit and the output device
Output the patch, and the patch output by this output device
Is read by the patch reading unit. γ characteristic determination unit
Calculates the γ characteristic from the output signal of the patch reading unit and
The positive curve determination unit creates the γ characteristic from the γ characteristic determination unit in advance.
Generate a target γ correction curve from the previously set target γ characteristics.
It The γ-correction curve synthesizing unit is supplied from the γ-correction curve selecting unit.
Predetermined calculation of the obtained γ correction curves for multiple density areas
Further, they are combined into a combined γ correction curve. Deviation value determination unit
Is the combined γ correction curve from the γ correction curve combination unit
It is the deviation from the target γ correction curve from the positive curve determination section.
The combined γ correction curve is larger than the target γ correction curve.
From the deviation of 1 and the target γ correction curve, the combined γ correction curve is
A small second deviation is calculated for each concentration area and each concentration region is calculated.
The larger deviation of the first deviation and the second deviation for each region
Maximum deviation. The γ correction curve selection value manipulated variable determiner
From the output signal of the deviation value determination unit, the maximum
For the density area where the deviation is maximum, the first deviation is the second
The first deviation that is larger than the deviation is the positive deviation threshold of the density region.
When it is larger, the γ correction of the γ correction curve of the density region
If the amount is not the minimum, the γ correction of the γ correction curve of the density region
Γ correction curve selection value operation amount so that the amount is reduced by m steps
Is determined and the γ correction amount of the γ correction curve in the density area is the minimum.
If so, the γ correction curve of the density area adjacent to the density area
Select the γ correction curve so that the γ correction amount of
The value manipulated variable is determined, and the maximum deviation is
The first deviation is greater than the second deviation for large density areas
If the second deviation is not larger than the negative deviation threshold of the density region
When it is large, the γ correction amount of the γ correction curve in the density region is
If it is not the maximum, the γ correction amount of the γ correction curve in the density region is
Decide the manipulated value of the selected value of the γ correction curve so that it will be increased by n steps.
The γ correction amount of the γ correction curve in the density region is the maximum
Then, γ of the γ correction curve of the density region adjacent to the density region
Select the γ correction curve so that the correction amount is increased by n steps.
Determine the crop. The γ correction curve selection section
Of the γ correction curve for each density area from the selected value manipulated variable determiner
Gamma correction curves for multiple density areas based on the selected value operation amount
To the γ-correction curve composition section,
The first deviation and the second deviation of are within the threshold of each density region
Sometimes the γ correction unit corrects the γ characteristic with the combined γ correction curve
To do.

According to the invention of claim 3, claim 1 or
In the image processing device described in 2, the γ correction curve selection value operation
Selection of the γ correction curve for each concentration area determined by the cropping unit
The selected value operation amount is operated back and forth in P steps to obtain multiple concentration ranges.
The γ correction curve that minimizes the deviation of the range is selected.

[0014]

[0015]

[0016]

FIG. 1 shows a first embodiment of the present invention. This first
The embodiment is an embodiment of the invention described in claim 1 and is an example of a printer. Normally, the input signal is γ-corrected by the γ-correction unit 21, and the γ-characteristics, that is, the relationship between the writing value of the image processing unit 22 including the dither processing unit and the density or reflectance of the output image of the output device 23 is corrected. Then, the output signal of the γ correction unit 21 is selected by the selector 24 and input to the output device 23. The output device 23 outputs an image according to the input signal from the selector 24.

As the output device 23, an electrophotographic output device or another output device is used. FIG. 2 shows an example of an electrophotographic output device. In this output device, for example, a photoconductor drum 25 is used as a photoconductor, and at the time of image output, the photoconductor drum 25 is rotationally driven by a motor and uniformly charged by a charging unit 26, and then image exposure from an exposure unit 27 is performed. An electrostatic latent image is formed by writing an image.
The electrostatic latent image is developed into a toner image by the developing unit 28, and the recording paper is fed from the paper feeding device 29 to the registration roller 30.

The registration roller 30 sends out the recording paper in accordance with the toner image on the photoconductor drum 25, and the transfer unit 31 transfers the toner image on the photoconductor drum 25 to the recording paper and the separating unit 32 forms the photoconductor on the photoconductor. After being separated from the drum 25, the toner image is fixed by the fixing unit 33 and discharged to the outside. Further, the photosensitive drum 25 is cleaned by a cleaning device after the recording paper is separated to prepare for the next image forming operation.

The exposure time counter 34 includes an exposure unit 27.
The exposure time of the photosensitive drum 25 is measured, and the surface potential meter 35 measures the charging potential and the exposure portion potential of the photosensitive drum 25 between the exposure portion 27 and the developing portion 35. The toner concentration meter 36 measures the toner concentration of the two-component developer in the developing section 28. The copy counter 37 counts the number of times the registration roller 30 sends out the recording paper, and the image density sensor 3
Reference numeral 8 measures the density of the toner image on the photosensitive drum 25 when the toner image on the photoconductor drum 25 passes through the transfer unit 31 and the separation unit 32 without being transferred to the recording paper. The drum rotation speed counter 39 counts the rotation speed of the photosensitive drum 25, and the temperature sensor 40 and the humidity sensor 41 measure the temperature and the humidity.

When selecting the optimum γ correction curve,
As shown in FIG. 1, the patch signal generated by the patch generation unit 42 is selected by the selector 24 and input to the dither processing unit 22, and the signal of an arbitrary patch is input to the dither processing unit 2.
2 can be entered. Where the patch is gray,
It includes monochromatic and mixed color patches. Selector 24
The patch signal from 1 is subjected to dither processing by the dither processing unit 22 and input to the output device 23, and the output device 23 outputs a patch by the patch signal from the dither processing unit 22 to create a patch sample 43. The patch reading unit 44 reads the patch sample 43.

The patch reading section 44 includes, for example, a densitometer for measuring the density of the patch sample 43, a color difference meter for measuring the color difference of the patch sample 43, a scanner for reading the patch sample 43 (such as a scanner inside the copying machine), and the electronic device described above. Patch sample 43 used in photographic output devices
Density sensor 3 for measuring the density and latent image potential (density of patch formed on photoconductor drum 25 and latent image potential)
8. The surface electrometer 35 can be used.

The output signal of the patch reading unit 44 is a density signal from the densitometer when the patch reading unit 44 is a densitometer, and L * from the color difference meter when the patch reading unit 44 is a color difference meter. a *, b *, L :, u *, v *, and other color signals in a uniform color space, and the integrated value of the spectral reflectance, and when the patch reading unit 44 is a scanner, R, G, B signals, Y, If the M, C, K signals and the patch reading unit 44 are the image density sensor 38 and the surface potential meter 35, A /
This is a signal obtained by correcting the output signal after D conversion so as to obtain the γ characteristic of the printer.

The patch generation unit 42 generates a patch signal that obtains the γ characteristic (output γ characteristic) of the printer, and the patch sample 43 is read by the patch reading unit 44. The γ characteristic determination unit 45 obtains a γ characteristic signal by linearly interpolating the output signal of the patch reading unit 44 as shown in FIG. As shown in FIG. 12, the target γ correction curve determination unit 46 determines a target from the signal of the printer γ characteristic that is the output signal of the γ characteristic determination unit 45 and the signal of the target γ characteristic (target input / output characteristic) that is created in advance. A signal of the γ correction curve is generated.

The γ correction curve is divided into a highlight area, a middle area, and a shadow area as shown in FIG. 13, and a highlight portion γ correction curve selection value operation amount determination portion 47 and a middle portion γ correction curve selection value operation amount determination portion are determined. Part 48, shadow part γ
The correction curve selection value manipulated variable determiner 49 displays the highlight area,
The γ correction curve selection value operation amount of each of the middle area and the shadow area is held. The highlight part γ correction curve selection value manipulated variable determiner 47, the middle part γ correction curve selected value manipulated variable determiner 48, and the shadow part γ correction curve selected value manipulated variable determiner 49 include a highlight region, a middle region, and a shadow region. An initial value is set in advance as each γ correction curve selection value operation amount in the area, for example, 0, 0, 0 is set.

The highlight section γ correction curve selection section 50, the middle section γ correction curve selection section 51, and the shadow section γ correction curve selection section 52 are respectively a highlight section γ correction curve selection value operation amount determination section 47 and a middle section γ. The highlight area, the middle area according to the γ correction curve selection value operation amount of each of the highlight area, the middle area, and the shadow area from the correction curve selection value operation amount determination portion 48 and the shadow portion γ correction curve selection value operation amount determination portion 49. Each γ correction curve selection value in the area and the shadow area changes.

The highlight part γ correction part 53, the middle part γ correction part 54, and the shadow part γ correction part 55 are constituted by a LUT system using a ROM as shown in FIG.
The data of each γ correction curve of the highlight area, the middle area, and the shadow area as shown in FIG. 5 is stored.
This highlight part γ correction part 53, middle part γ correction part 5
4. The shadow section γ correction section 55 is for selecting the highlight area, the middle area, and the shadow area from the highlight section γ correction curve selection section 50, the middle section γ correction curve selection section 51, and the shadow section γ correction curve selection section 52, respectively. Data of each γ correction curve in the highlight area, middle area, and shadow area is selected and output according to each γ correction curve selection value.

As shown in FIG. 6, the γ correction curve synthesizing section 56 includes a highlight section γ correcting section 53 and a middle section γ correcting section 5.
4. A γ correction curve is synthesized by averaging the data of each γ correction curve of the highlight area, the middle area, and the shadow area from the shadow section γ correction section 55, and the synthesized γ correction curve is synthesized. Call. The deviation value determination unit 57, for example, when the number of gradations of the output device 23 is N and 0
<Highlight area <N / 3, N / 3 <Middle area <2N
/ 3, 2N / 3 ≦ shadow area <N, and the signal of the target γ correction curve from the target γ correction curve determination unit 46 and the γ correction curve for each density area (highlight area, middle area, shadow area) The average value of the difference from the signal of the synthetic γ correction curve from the synthesizing unit 56 is calculated, and γ for each density region is calculated.
The average value of the correction curve is used as the deviation of the highlight area, middle area, and shadow area.

Highlight portion γ correction curve selection value manipulated variable determiner 47, middle portion γ correction curve selected value manipulated variable determiner 4
8. Shadow portion γ correction curve selection value manipulated variable determiner 49
Is the γ correction curve selection value operation amount for each of the highlight area, middle area, and shadow area so that all combinations of a plurality of γ correction curves for each density area (highlight area, middle area, shadow area) are selected. The γ correction curves for the highlight area, the middle area, and the shadow area are selected when the deviations from the deviation value determining unit 57 for each density area (highlight area, middle area, shadow area) are minimized by operating sequentially. determining a value operation amount to the value at this time. Further, the deviation determination unit 62 compares the deviation for each density area (highlight area, middle area, shadow area) from the deviation value determination unit 57 with the threshold value for each density area, and the deviation value determination unit 57.
The gate 58 is opened when the deviation of each density area from the respective values becomes equal to or less than the threshold value of each density area. Therefore, the data of the combined γ correction curve from the γ correction curve combination unit 56 is set to the γ correction unit 21 through the gate 58 as the optimum γ correction curve data, and the γ correction unit 21 sets the set γ correction curve.
Γ correction of the input signal is performed based on the correction curve data.

In the first embodiment, the γ correction curve selection value operation amounts for the highlight area, the middle area, and the shadow area are sequentially determined so as to select all combinations of the plurality of γ correction curves for each density area. Then, when the deviation for each density region from the deviation value determining unit 57 becomes the minimum, the gate 58 is opened and the data of the combined γ correction curve is set in the γ correction unit 21, so that the optimum γ correction curve is selected. be able to.

FIG. 7 shows a second embodiment of the present invention. The second embodiment is an embodiment of the invention described in claim 2. First
In the embodiment, the highlight portion γ correction curve selection value manipulated variable determiner 47 and the middle portion γ correction curve selected value manipulated variable determiner 4
8. Shadow region γ correction curve selection value operation amount determining unit 49 manipulates each γ correction curve selection value in the highlight region, middle region, and shadow region so that all combinations of a plurality of γ correction curves in each density region are selected. Since the amount is sequentially determined, the time required to select the optimum γ correction curve cannot be shortened sufficiently. In order to solve this problem, it is only necessary to obtain the γ correction curve when the deviation of each density region is within the threshold value.

Therefore, in the second embodiment, in the first embodiment, the highlight part γ correction curve selection value manipulated variable determiner 59 and the middle part γ correction curve selected value manipulated variable determiner 6 are used.
0, shadow part γ correction curve selection value manipulated variable determiner 61
Is the γ correction curve selection value operation amount for each of the highlight area, middle area, and shadow area so that all combinations of a plurality of γ correction curves for each density area (highlight area, middle area, shadow area) are selected. The γ-correction curve selection for each density region is performed when the deviation for each density region (highlight region, middle region, shadow region) from the deviation value determination unit 57 is within the threshold value for each density region by operating sequentially. The value manipulated variable is set to the value at this time. Highlight section γ correction curve selection section 50, middle section γ correction curve selection section 5
1, the shadow part γ correction curve selection part 52 is a highlight part γ correction curve selection value operation amount determination part 59, a middle part γ correction curve selection value operation amount determination part 60, and a shadow part γ correction curve selection value operation amount determination part 60. Each γ correction curve selection value of the highlight region, the middle region, and the shadow region from the unit 61 changes in accordance with the operation amount of each γ correction curve selection value of the highlight region, the middle region, and the shadow region.

Further, the deviation determining section 62 includes a deviation value determining section 5
The deviation of each density area (highlight area, middle area, shadow area) from 7 is compared with the threshold value of each density area, and the deviation of each density area from the deviation value determination unit 57 is calculated for each density area. The gate 58 is opened when the voltage becomes less than the threshold value. Therefore, the combined γ correction curve data from the γ correction curve combining unit 56 is set as the optimum γ correction curve data in the γ correction unit 21 through the gate 58, and the γ correction unit 21 sets the set γ correction curve data. The γ correction of the input signal is performed by. In the second embodiment, it is not necessary to select all the combinations of the plurality of γ correction curves in each density region, so that the γ correction curve can be selected in a shorter time than in the first embodiment.

FIG. 8 shows a third embodiment of the present invention. The third embodiment is an embodiment of the invention described in claim 3. In the second embodiment, the optimum γ correction curve can be selected in a shorter time than in the first embodiment, but it still takes a long time to select the optimum γ correction curve. In order to solve this problem, the γ correction curve selection value operation amount may be determined according to the deviation between the target γ correction curve obtained in advance and the selected combined γ correction curve.

Therefore, in the third embodiment, in the second embodiment, the deviation value determining unit 63, for example, the number of gradations of the output device 23 is N and 0 ≦ highlight area <N / 3, N /
3 ≤ middle area <2N / 3, 2N / 3 ≤ shadow area <
Assuming that N is N, the γ correction curve synthesizing unit 5 uses the signal of the target γ correction curve from the target γ correction curve determination unit 46 for each density region (highlight region, middle region, shadow region).
The deviation of a portion of the signal of the combined γ correction curve from 6 (referred to as a first deviation) and the target γ correction curve determination unit 46.
The deviation (referred to as the second deviation) is calculated for the portion where the signal of the combined γ correction curve from the γ correction curve combining unit 56 is smaller than the signal of the target γ correction curve from.

Highlight portion γ correction curve selection value manipulated variable determiner 64, middle portion γ correction curve selected value manipulated variable determiner 6
5, shadow portion γ correction curve selection value manipulated variable determiner 66
Is the largest deviation of the first deviation and the second deviation for each density area from the output signal of the deviation value determination unit 63, and the first deviation and the second deviation of each density area Is less than or equal to the threshold value for each density region, or when the number of repetitions of the γ correction curve selection value operation amount reaches the specified number, the γ correction curve selection value operation amount of each density region is determined to the value at this time. .

Further, in the highlight part γ correction curve selection value manipulated variable determiner 64, the middle part γ correction curve selected value manipulated variable determiner 65, and the shadow part γ correction curve selected value manipulated variable determiner 66, each density area Of the density regions having the largest maximum deviation (hereinafter referred to as the maximum deviation density regions), the γ-correction curve selection value manipulated variable is determined from the output signal of the deviation value determination unit 63 from the maximum deviation density region. When the first deviation is larger than the second deviation and the first deviation is larger than the positive deviation threshold value of the density area of maximum deviation, the γ correction curve selection value operation amount of the density area of maximum deviation is set to the density area of maximum deviation. The γ correction curve selection value operation amount for the density region with the maximum deviation is set to γ for the density region with the maximum deviation.
When the correction curve cannot be manipulated to be smaller by m steps, the γ correction curve selection value operation amount in the density region with the maximum deviation is set to the minimum value, and the γ correction curve in the density region with the maximum deviation is set to the minimum γ correction amount. .

Further, in each of the density areas of the highlight part γ correction curve selection value manipulated variable determiner 64, the middle part γ correction curve selected value manipulated variable determiner 65, and the shadow part γ correction curve selected value manipulated variable determiner 66. The deviation value determining unit 63 determines the γ correction curve selection value operation amount of the density area having the largest maximum deviation (hereinafter referred to as the maximum deviation density area).
From the output signal of the above, when the first deviation is not larger than the second deviation in the density area of the maximum deviation, and when the second deviation is larger than the negative deviation threshold value of the density area of the maximum deviation, γ correction of the density area of the maximum deviation is performed. The γ correction curve in the density region where the deviation of the curve selection value operation amount is maximum is increased by n (a positive integer) (γ
The correction amount is increased by n steps, and if the γ correction curve selection value operation amount in the density area with the maximum deviation cannot be operated so that the γ correction curve in the density area with the maximum deviation is increased by n steps, the maximum deviation is obtained. Γ-correction curve for density area γ-correction curve for density area with maximum deviation
The correction amount should be the maximum.

The highlight section γ correction curve selection section 50, the middle section γ correction curve selection section 51, and the shadow section γ correction curve selection section 52 are respectively a highlight section γ correction curve selection value operation amount determination section 64 and a middle section γ. The highlight area, the middle area according to the γ correction curve selection value operation amount of each of the highlight area, middle area, and shadow area from the correction curve selection value operation amount determination portion 65 and the shadow portion γ correction curve selection value operation amount determination portion 66. Each γ correction curve selection value in the area and the shadow area changes.

The deviation determining unit 62 compares the deviation for each density area from the deviation value determining unit 57 with the threshold value for each density area, and the deviation for each density area from the deviation value determining unit 57 is used for each density area. The gate 58 is opened when the value becomes equal to or less than the threshold value of the region or when the number of repetitions of the γ correction curve selection value operation amount reaches the designated number. Therefore, the combined γ correction curve data from the γ correction curve combining unit 56 is set as the optimum γ correction curve data in the γ correction unit 21 through the gate 58, and the γ correction unit 21 sets the set γ correction curve data. The γ correction of the input signal is performed by.

As a result of the experiment, the case of m = 1 and n = 1 was effective. In the third embodiment, a plurality of γ in each density region
Since you can reduce the number of combinations of correction curves to be selected,
The γ correction curve can be selected in a shorter time than in the second embodiment.

FIG. 9 shows a fourth embodiment of the present invention. The fourth embodiment is an embodiment of the invention described in claim 4. The third embodiment has a problem that it is not always possible to select the optimum γ correction curve. In order to solve this problem, the γ correction curve selection value operation amount of the density area adjacent to the density area having the maximum deviation may be operated.

Therefore, in the fourth embodiment, in the third embodiment, the highlight part γ correction curve selection value manipulated variable determiner 67 and the middle part γ correction curve selected value manipulated variable determiner 6 are used.
8. Shadow part γ correction curve selection value manipulated variable determiner 69
Is the largest deviation of the first deviation and the second deviation for each density area from the output signal of the deviation value determination unit 63, and the first deviation and the second deviation of each density area Is less than or equal to the threshold value for each density region, or when the number of repetitions of the γ correction curve selection value operation amount reaches the specified number, the γ correction curve selection value operation amount of each concentration region is determined as the operation amount at this time. To do.

Further, each density area in the highlight part γ correction curve selection value manipulated variable determiner 67, the middle part γ correction curve selected value manipulated variable determiner 68, and the shadow part γ correction curve selected value manipulated variable determiner 69 Among the above, the one that determines the γ correction curve selection value manipulated variable in the density area having the largest maximum deviation (the density area having the largest deviation) is the first in the density area having the largest deviation from the output signal of the deviation value determination unit 63. Deviation is larger than the second deviation and the first deviation is larger than the positive deviation threshold value of the maximum deviation density area, the γ correction curve selection value operation amount of the maximum deviation density area is corrected to the maximum deviation deviation area. The curve is manipulated to be smaller by m steps, and the γ correction curve selection value operation amount in the density area with the maximum deviation is set to γ in the density area with the maximum deviation.
When the correction curve cannot be manipulated to be smaller by m steps, the γ correction curve selection value operation amount in the density region with the maximum deviation is set to the minimum value, and the γ correction curve in the density region with the maximum deviation is set to the minimum γ correction amount. .

Further, the highlight part γ correction curve selection value manipulated variable determiner 67, the middle part γ correction curve selected value manipulated variable determiner 68, the shadow part γ correction curve selected value manipulated variable determiner 69 is a deviation value determiner. From the output signal of 63, when the first deviation is larger than the second deviation in the concentration maximum deviation area, the first deviation
Is larger than the positive deviation threshold of the density area of maximum deviation, the γ correction curve selection value operation amount of the density area of maximum deviation is the minimum value, and the γ correction curve of the density area of maximum deviation is γ.
When the correction amount is the minimum, the γ correction curve selection value operation amount adjacent to the high density region side of the density region with the maximum deviation (hereinafter referred to as the adjacent high density region) is set to the adjacent high density region. If the γ-correction curve cannot be manipulated so that the γ-correction curve selection value operation amount of the adjacent high-concentration region is reduced by m steps, the γ-correction curve of the adjacent high-concentration region is reduced by m steps. It is assumed that the γ correction curve selection value operation amount in the density region is set to the minimum value and the γ correction curve in the adjacent high density region is set to the minimum γ correction amount.

Further, of the highlight part γ correction curve selection value manipulated variable determiner 67, the middle part γ correction curve selected value manipulated variable determiner 68, and the shadow part γ correction curve selected value manipulated variable determiner 69, the maximum deviation is determined. What determines the γ correction curve selection value manipulated variable in the density region is the second deviation when the first deviation is not larger than the second deviation in the maximum density region of the deviation from the output signal of the deviation value determination unit 63. Is larger than the negative deviation threshold value of the maximum deviation density area, the γ correction curve selection value operation amount of the maximum deviation density area is set to γ of the maximum deviation density area.
The correction curve is operated to increase by n steps (the γ correction amount increases by n steps), and the γ correction curve selection value operation amount of the density area with the maximum deviation is set to the γ correction curve of the density area with the maximum deviation.
When the operation cannot be performed in such a manner that the step size becomes larger, the γ correction curve selection value operation amount in the density region with the maximum deviation is set to the maximum value, and the γ correction curve in the density region with the maximum deviation has the maximum γ correction amount.

Further, the highlight part γ correction curve selection value operation amount determining part 67, the middle part γ correction curve selection value operating amount determining part 68, the shadow part γ correction curve selection value operating amount determining part 69 is a deviation value determining part. From the output signal of 63, when the first deviation is not larger than the second deviation in the density area of maximum deviation and the second deviation is larger than the negative deviation threshold value of the density area of maximum deviation, γ of the density area of maximum deviation is When the correction curve selection value operation amount is the maximum value and the γ correction curve of the density region with the maximum deviation has the maximum γ correction amount, γ of the adjacent high density region adjacent to the density region with the maximum deviation is The correction curve selection value operation amount is operated so that the γ correction curve of the adjacent high density region is increased by n steps, and the γ correction curve selection value operation amount of the adjacent high density region is set to the γ correction curve of the adjacent high density region. n
If the operation cannot be performed in a stepwise manner, the γ correction curve selection value operation amount of the adjacent high density region is set to the maximum value, and the γ correction curve of the adjacent high density region is set to the maximum γ correction amount.

The highlight section γ correction curve selection section 50, the middle section γ correction curve selection section 51, and the shadow section γ correction curve selection section 52 are respectively a highlight section γ correction curve selection value operation amount determining section 67 and a middle section γ. The highlight area, the middle area according to the γ correction curve selection value operation amount of each of the highlight area, the middle area, and the shadow area from the correction curve selection value operation amount determination section 68 and the shadow section γ correction curve selection value operation amount determination section 69. Each γ correction curve selection value in the area and the shadow area changes.

The deviation determining section 62 compares the deviation for each density area from the deviation value determining section 57 with the threshold value for each density area, and the deviation for each density area from the deviation value determining section 57 is calculated for each density area. The gate 58 is opened when the value becomes equal to or less than the threshold value of the region or when the number of repetitions of the γ correction curve selection value operation amount reaches the designated number. Therefore, the combined γ correction curve data from the γ correction curve combining unit 56 is set as the optimum γ correction curve data in the γ correction unit 21 through the gate 58, and the γ correction unit 21 sets the set γ correction curve data. The γ correction of the input signal is performed by.

As a result of the experiment, the case of m = 1 and n = 1 was effective. In the fourth embodiment, a plurality of γ in each density region
Since you can reduce the number of combinations of correction curves to be selected,
It is possible to select the γ correction curve with high accuracy in a shorter time than in the second embodiment.

FIG. 10 shows a fifth embodiment of the present invention. The fifth embodiment is an embodiment of the invention described in claim 5. In the third and fourth embodiments, the optimum γ correction curve cannot always be selected. In order to solve this problem, the γ correction curve for each density region may be selected so that the deviation between the target γ correction curve and the combined γ correction curve is minimized.

Therefore, in the fifth embodiment, in the third embodiment, the highlight part γ correction curve selection value manipulated variable determiner 70 and the middle part γ correction curve selected value manipulated variable determiner 7 are used.
1, shadow portion γ correction curve selection value operation amount determination unit 72
Respectively, the highlight part γ correction curve selection value manipulated variable determiner 64, the middle part γ correction curve selected value manipulated variable determiner 65, and the shadow part γ correction curve selected value manipulated variable determiner 6 respectively.
As in the case of 6, the γ correction curve selection value operation amount of each density region is determined, and the γ correction curve selection value operation amount of each density region is increased / decreased by one step to p steps, thereby highlighting the γ correction curve. Each γ of the selection section 50, the middle section γ correction curve selection section 51, and the shadow section γ correction curve selection section 52
The correction curve selection value is increased / decreased one step at a time to p steps.

For this reason, the highlight part γ correction part 53, the middle part γ correction part 54, and the shadow part γ correction part 55 have a highlight part γ correction curve selection value operation amount determination part 70 and a middle part γ correction curve selection value. Manipulation amount determination unit 71, shadow unit γ
One type of γ correction curve for each density region corresponding to the γ correction curve selection value manipulated variable of each density region determined by the correction curve selection value manipulated variable determiner 72, and 2p types that are increased or decreased by one step to p levels Then, each combination with the γ correction curve of each density region is sequentially selected and the data is output. The deviation determination unit 73 determines the minimum value of the deviation between the target γ correction curve and the combined γ correction curve from the output signal of the deviation value determination unit 63, and the deviation between the target γ correction curve and the combined γ correction curve is minimized. At this time, the gate 58 is opened so that the data of the combined γ correction curve from the γ correction curve combination unit 56 at this time is set in the γ correction unit 21 through the gate 58 as the optimum γ correction curve data.

As a result of the experiment, the case of m = 1, n = 1, p = 1 or 2 was effective. In the fifth embodiment, it is possible to reduce the number of combinations of a plurality of γ correction curves to be selected for each density region, so that a γ correction curve can be selected at high speed and with high accuracy.

The sixth embodiment of the present invention is an embodiment of the invention described in claim 5. The sixth embodiment is the same as the fourth embodiment except that the highlight part γ correction curve selection value manipulated variable determiner 67 and the middle part γ correction curve selected value manipulated variable determiner 6 are used.
8. The shadow portion γ correction curve selection value manipulated variable determiner 69 determines the γ correction curve selection value manipulated variable for each density area as described above, and the determined density areas are determined as in the fifth embodiment. Each of the γ corrections of the highlight part γ correction curve selection part 50, the middle part γ correction curve selection part 51, and the shadow part γ correction curve selection part 52 by increasing or decreasing the γ correction curve selection value operation amount The curve selection value is increased / decreased by one step to p steps, and the deviation determination unit 73 determines the minimum value of the deviation between the target γ correction curve and the combined γ correction curve from the output signal of the deviation value determination unit 63 to determine the target γ. The gate 58 is opened when the deviation between the correction curve and the combined γ correction curve is minimized, and the same effect as the fifth embodiment can be obtained.

[0055]

As described above, according to the first aspect of the present invention, the image processing unit for performing the predetermined image processing on the input signal, and the output device for outputting the image by the output signal of the image processing unit. An image processing device having a γ correction unit for correcting the γ characteristic of the write value of the image processing unit and the output image of the output device, the signal of the patch being input to the image processing unit From the output device, a γ characteristic determining unit that obtains a γ characteristic from an output signal of the patch reading unit, and a γ characteristic determining unit a γ-correction-curve determining unit that generates a target γ-correction curve from the γ-characteristics and the target γ-characteristic created in advance,
As a γ correction curve for correcting the γ characteristic in the γ correction unit, the γ correction curves of a plurality of given density regions are combined by a predetermined calculation to form a combined γ correction curve γ.
A correction curve combining unit, a combined γ correction curve from this γ correction curve combining unit, and a target γ from the γ correction curve determining unit.
A deviation value determination unit that calculates the deviation from the correction curve for each density region, and a γ correction curve selection value operation that determines the selected value operation amount of the γ correction curve for each density region from the output signal of this deviation value determination unit And the γ-correction-curve composition by selecting the γ-correction curves of a plurality of density regions based on the selected-value operation amount of the γ-correction curve for each density region from the γ-correction curve selection-value operation amount determination unit. And a γ correction curve selection section for giving a γ correction curve selection value operation amount determination section.
Since the selected value operation amount of the γ correction curve for each density region is determined so that the deviation of each density region between the correction curve and the target γ correction curve is minimized, the optimum γ correction curve can be selected.

According to the second aspect of the present invention, an image processing unit for performing a predetermined image processing on the input signal, an output device for outputting an image by the output signal of the image processing unit, and the image processing unit. In an image processing apparatus having a γ correction unit for correcting the γ characteristic of a writing value and an output image of the output device, a patch for inputting a patch signal to the image processing unit and outputting the patch to the output device A generation unit, a patch reading unit that reads a patch output by the output device, a γ characteristic determination unit that obtains a γ characteristic from an output signal of the patch reading unit, and a γ characteristic determination unit that determines the γ characteristic.
A γ correction curve determination unit that generates a target γ correction curve from the characteristics and a target γ characteristic that has been created in advance, and a plurality of given γ correction curves for correcting the γ characteristic by the γ correction unit. A γ-correction curve synthesizing unit for synthesizing the γ-correction curve in the density region by a predetermined calculation to form a synthetic γ-correction curve, a synthetic γ-correction curve from this γ-correction-curve synthesizing unit, and a target γ from the γ-correction-curve determining unit. A deviation value determination unit that calculates the deviation from the correction curve for each density region, and a γ correction curve selection value operation that determines the selected value operation amount of the γ correction curve for each density region from the output signal of this deviation value determination unit And the γ-correction-curve composition by selecting the γ-correction curves of a plurality of density regions based on the selected-value operation amount of the γ-correction curve for each density region from the γ-correction curve selection-value operation amount determination unit. Selection of γ correction curve given to department And the γ
Since the correction curve selection value operation amount determination unit determines the selection value operation amount of the γ correction curve for each density region so that the deviation of each density region between the combined γ correction curve and the target γ correction curve is equal to or less than the threshold value, It is possible to shorten the time required to select the γ correction curve.

According to the third aspect of the present invention, an image processing section for performing a predetermined image processing on the input signal, an output device for outputting an image by the output signal of the image processing section, and the image processing section In an image processing apparatus having a γ correction unit for correcting the γ characteristic of a writing value and an output image of the output device, a patch for inputting a patch signal to the image processing unit and outputting the patch to the output device A generation unit, a patch reading unit that reads a patch output by the output device, a γ characteristic determination unit that obtains a γ characteristic from an output signal of the patch reading unit, and a γ characteristic determination unit that determines the γ characteristic.
A γ correction curve determination unit that generates a target γ correction curve from the characteristics and a target γ characteristic that has been created in advance, and a combined γ correction curve that is obtained by synthesizing the γ correction curves of a plurality of given density regions by a predetermined calculation. Γ correction curve synthesizing unit
A deviation between the combined γ correction curve from the correction curve combination unit and the target γ correction curve from the γ correction curve determination unit, which is larger than the target γ correction curve in the combined γ correction curve, and the target γ correction curve. A second deviation whose synthetic γ correction curve is smaller than the curve is calculated for each density area, and a deviation value is determined for each density area, with the larger deviation of the first deviation and the second deviation being the maximum deviation. Section and the output signal of the deviation value determining section, when the first deviation is larger than the positive deviation threshold value of the density area for the density area having the largest maximum deviation among the density areas, the γ correction of the density area is performed. The selected value operation amount of the γ correction curve is determined so that the γ correction amount of the curve is reduced by m steps, and the first deviation is larger than the positive deviation threshold value of the density region and the second deviation is the density of the density region. When it is larger than the negative deviation threshold of the area, Of the γ correction curve of degree area γ
A γ correction curve selection value operation amount determining unit that determines the selection value operation amount of the γ correction curve so that the correction amount increases by n steps, and a γ correction for each density region from the γ correction curve selection value operation amount determining unit A γ-correction curve selecting section for selecting γ-correction curves of a plurality of density areas based on the selected value operation amount of the curve and giving the γ-correction curve synthesizing section, a first deviation and a second deviation of all the density areas Since the [gamma] correction unit includes means for correcting the [gamma] characteristic with the combined [gamma] correction curve when is within the threshold of each density region, the time required for selecting the [gamma] correction curve can be shortened.

According to the invention described in claim 4, an image processing section for performing a predetermined image processing on an input signal, an output device for outputting an image by an output signal of the image processing section, and the image processing section of the image processing section. In an image processing apparatus having a γ correction unit for correcting the γ characteristic of a writing value and an output image of the output device, a patch for inputting a patch signal to the image processing unit and outputting the patch to the output device A generation unit, a patch reading unit that reads a patch output by the output device, a γ characteristic determination unit that obtains a γ characteristic from an output signal of the patch reading unit, and a γ characteristic determination unit that determines the γ characteristic.
A γ correction curve determination unit that generates a target γ correction curve from the characteristics and a target γ characteristic that has been created in advance, and a combined γ correction curve that is obtained by synthesizing the γ correction curves of a plurality of given density regions by a predetermined calculation. Γ correction curve synthesizing unit
A deviation between the combined γ correction curve from the correction curve combination unit and the target γ correction curve from the γ correction curve determination unit, which is larger than the target γ correction curve in the combined γ correction curve, and the target γ correction curve. A second deviation whose synthetic γ correction curve is smaller than the curve is calculated for each density area, and a deviation value is determined for each density area, with the larger deviation of the first deviation and the second deviation being the maximum deviation. Section and the output signal of the deviation value determining section, the first deviation is larger than the second deviation and the first deviation is positive in the density area in the density area having the largest maximum deviation among the plurality of density areas. If the γ correction amount of the γ correction curve of the density region is not the minimum when the deviation threshold value is larger than the deviation threshold, the selected value operation amount of the γ correction curve is set so that the γ correction amount of the γ correction curve of the density region is reduced by m steps. Γ correction amount of the γ correction curve of the determined density region Is the minimum, the γ correction amount of the γ correction curve of the density area adjacent to the density area is m.
The selected value operation amount of the γ correction curve is determined so as to become smaller, and the first deviation is not larger than the second deviation in the density area having the largest maximum deviation among the plurality of density areas, and the second deviation is determined. Is larger than the negative deviation threshold of the density region,
If the γ correction amount of the γ correction curve in the density region is not the maximum, the selected value operation amount of the γ correction curve is determined so that the γ correction amount of the γ correction curve in the density region is increased by n steps, and If the γ correction amount of the γ correction curve is the maximum, the γ correction curve selection is performed so that the γ correction amount of the γ correction curve in the density region adjacent to the density region is increased by n steps. The γ correction curve for a plurality of density regions is selected based on the value manipulated variable determining unit and the selected value manipulated variable of the γ correction curve for each density region from the γ correction curve selection value manipulation amount determining unit. The γ correction curve selection unit to be given to the curve synthesizing unit, and the γ correction unit to the γ correction unit by the synthetic γ correction curve when the first deviation and the second deviation of all the density regions are within the threshold value of each density region. Since it has a means for correcting the characteristics, It is possible to select with high accuracy in a short time.

According to the fifth aspect of the invention, in the image processing apparatus according to the third or fourth aspect, the selection value operation of the γ correction curve of each density region determined by the γ correction curve selection value operation amount determination unit is performed. Since the means for selecting the γ correction curve that minimizes the deviation between the plurality of density regions by operating the amount forward and backward by P steps, the γ correction curve can be selected at high speed and with high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic view showing an example of an output device used in the first embodiment.

FIG. 3 is a characteristic curve diagram showing a highlight region γ correction curve in the first embodiment.

FIG. 4 is a characteristic curve diagram showing a middle area γ correction curve in the first embodiment.

FIG. 5 is a characteristic curve diagram showing a shadow region γ correction curve in the first embodiment.

FIG. 6 is a diagram showing a synthesis example of a γ correction curve in the first embodiment.

FIG. 7 is a block diagram showing a second embodiment of the present invention.

FIG. 8 is a block diagram showing a third embodiment of the present invention.

FIG. 9 is a block diagram showing a fourth embodiment of the present invention.

FIG. 10 is a block diagram showing a fifth embodiment of the present invention.

FIG. 11 is a characteristic curve diagram showing an example of linear interpolation of a γ characteristic in the above embodiment.

FIG. 12 is a characteristic curve diagram showing an example of setting a target γ correction curve in the above embodiment.

FIG. 13 is a diagram showing a γ correction curve and each density region in the above embodiment.

FIG. 14 is a block diagram showing an example of a conventional printer.

FIG. 15 is a characteristic curve diagram showing a γ correction curve used in the printer.

FIG. 16 is a block diagram showing a LUT type γ correction unit used in the printer.

[Explanation of symbols]

21 γ correction unit 22 image processing unit 23 output device 24 selector 42 patch generation unit 44 patch reading unit 45 γ characteristic determination unit 46 target γ correction curve determination unit 47, 59, 64, 67, 70 highlight portion γ correction curve selection value Manipulation amount determination unit 48, 60, 65, 68, 71 Middle portion γ correction curve selection value Manipulation amount determination unit 49, 61, 66, 69, 72 Shadow portion γ correction curve selection value Manipulation amount determination unit 50 Highlight portion γ correction Curve selection section 51 Middle section γ correction curve selection section 52 Shadow section γ correction curve selection section 53 Highlight section γ correction section 54 Middle section γ correction section 55 Shadow section γ correction section 56 γ correction curve combination section 57, 62, 63, 73 deviation value determination unit 58 gate

Continuation of the front page (56) Reference JP-A 1-2222574 (JP, A) JP-A 5-323750 (JP, A) JP-A 6-62252 (JP, A) JP-A 7-95406 (JP , A) JP 7-221988 (JP, A) JP 7-162682 (JP, A) JP 6-292010 (JP, A) JP 6-46264 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04N 1/407 B41J 2/52 G06T 5/00 100

Claims (3)

(57) [Claims] 1. An image for performing predetermined image processing on an input signal.
An image is output by the image processing unit and the output signal of this image processing unit.
Output device, the writing value of the image processing unit and the
Γ correction for correcting the γ characteristic with the output image of the output device
In an image processing device having a
Input to the image processing unit and output the patch to the output device.
The patch generation unit and the output device.
And the patch reading section that reads the patch
And a γ characteristic determination unit that calculates the γ characteristic from the output signal of the
Γ characteristics from the γ characteristics determination unit of
γ correction curve decision to generate target γ correction curve from γ characteristics
The fixed part and the gamma correction curves for the given density areas
Γ-correction to make a combined γ-correction curve by combining by a certain calculation
The curve synthesizing unit and the synthesizing γ from this γ correction curve synthesizing unit
Correction curve and target γ correction from the γ correction curve determination unit
It is the deviation from the curve, and it is combined γ from the target γ correction curve.
The first deviation with a large correction curve and the target γ correction curve
The second deviation with a small combined γ correction curve
The first deviation and the second deviation are calculated for each concentration area
A deviation value determination unit that makes the larger deviation the maximum deviation,
From the output signal of this deviation value determination unit,
For the density area where the maximum deviation is maximum, the first deviation is
Γ of the density area when it is larger than the positive deviation threshold of the density area
The γ correction function is set so that the γ correction amount of the correction curve is reduced by m steps.
The selection value manipulated variable of the curve is determined, and the first
Of the second deviation is larger than the positive deviation threshold of the concentration area.
When the difference is larger than the negative deviation threshold of the concentration area, the concentration range is
Γ so that the γ correction amount of the γ correction curve in the range increases by n steps
Selection of correction curve γ correction curve selection that determines the manipulated variable
Value manipulated variable determiner and this γ correction curve selection value manipulated variable determine
To the selected value operation amount of the γ correction curve for each density area from the
Select γ correction curves for multiple density areas based on
The γ-correction curve selection section to give to the γ-correction curve composition section,
The first deviation and the second deviation of all density areas are
When it is within a threshold value, the γ correction unit is configured to
And a means for correcting the γ characteristic by means of a blur . 2. An image for performing predetermined image processing on an input signal.
An image is output by the image processing unit and the output signal of this image processing unit.
Output device, the writing value of the image processing unit and the
Γ correction for correcting the γ characteristic with the output image of the output device
In an image processing device having a
Input to the image processing unit and output the patch to the output device.
The patch generation unit and the output device.
And the patch reading section that reads the patch
And a γ characteristic determination unit that calculates the γ characteristic from the output signal of the
Γ characteristics from the γ characteristics determination unit of
γ correction curve decision to generate target γ correction curve from γ characteristics
The fixed part and the gamma correction curves for the given density areas
Γ-correction to make a combined γ-correction curve by combining by a certain calculation
The curve synthesizing unit and the synthesizing γ from this γ correction curve synthesizing unit
Correction curve and target γ correction from the γ correction curve determination unit
It is the deviation from the curve, and it is combined γ from the target γ correction curve.
The first deviation with a large correction curve and the target γ correction curve
The second deviation with a small combined γ correction curve
The first deviation and the second deviation are calculated for each concentration area
A deviation value determination unit that makes the larger deviation the maximum deviation,
From the output signal of this deviation value determination unit,
For the density area where the maximum deviation is the maximum, the first deviation is
The first deviation is larger than the deviation of 2 and the first deviation is the positive deviation of the density region.
When it is larger than the threshold value, γ of the γ correction curve of the density region
If the correction amount is not the minimum, γ of the γ correction curve of the density region
The selected value of the γ correction curve is manipulated so that the correction amount is reduced by m steps.
The amount of γ correction of the γ correction curve in the density area is determined
If it is the minimum, the gamma correction function of the density area adjacent to the density area
Of the γ-correction curve so that the
Determines the manipulated variable for the selected value and determines the maximum deviation among multiple density areas.
The first deviation is the second deviation for the density region where
The second deviation, which is not greater than the second deviation, is the negative deviation threshold of the density region.
When it is larger, the γ correction of the γ correction curve of the density region
If the amount is not the maximum, the γ correction of the γ correction curve of the density area
Γ correction curve selection value operation amount so that the amount increases by n steps
Is determined, and the γ correction amount of the γ correction curve in the density area is maximum.
If so, the γ correction curve of the density area adjacent to the density area
Selection of γ correction curve so that γ correction amount of
And γ correction curve selection択値operation amount determination unit that determines the value manipulated variables, a plurality of density areas on the basis of the selection value operation amount of γ correction curves for each density region from the γ correction curve selected value manipulated variable determiner Of the γ correction curves selected and given to the γ correction curve synthesizing unit, and when the first deviation and the second deviation of all the density regions are within the threshold of each density region, In the correction section, the γ
An image processing apparatus comprising: means for correcting characteristics. 3. The image processing apparatus according to claim 1 or 2.
The γ correction curve selection value manipulated variable determiner.
The selected value manipulated variable of the γ correction curve for each density area
Γ which minimizes the deviation of multiple density regions by step operation
An image processing apparatus comprising means for selecting a correction curve .