JP2002135559A - Image forming apparatus, image data processing method, and recording medium recording image data processing program - Google Patents

Abstract

(57) [Problem] When printing an image photographed by a digital camera or the like with an image forming apparatus such as a digital printer, the brightness (density) of a main subject such as a person's skin is appropriate. Thus, the brightness of the image data is corrected. An image is displayed on a monitor screen using image data to be corrected, and a main subject, such as a skin portion of a person, is specified using a mouse or the like. Next, pixel data included in the selected range is extracted from the image data, the average value of the luminance in the selected range is calculated, and the calculated average value of the luminance is set to a predetermined appropriate luminance value. Calculate the luminance correction amount. The entire image data is corrected using the obtained brightness correction value, and an image is formed using the corrected image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for correcting digital image data obtained by a scanner or a digital camera so that a main subject has an appropriate density.

[0002]

2. Description of the Related Art As a method of correcting the density of color digital image data, a method of correcting a histogram of each color component of RGB so that the average of the colors (densities) of all image data for each color of RGB becomes gray (gray). It has been known. This method is based on Evans's theorem that "when shooting a general outdoor scenery, mixing all the colors recorded in the image will make it close to gray".

[0003]

For example, an image in which a person is photographed without using a flash against a bright background or an image in which a person is photographed using a flash against a dark background is biased in density over the entire screen. When the density of certain image data is corrected by the above-described method, there is a problem that the person who is the main subject is not properly corrected due to the influence of the background.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an image forming apparatus, an image data processing method, and an image processing method capable of appropriately correcting the density of a main subject in an image. It is an object to provide a recording medium on which a data processing program is recorded.

[0005]

In order to achieve the above object, a first image forming apparatus according to the present invention provides an image reproducing apparatus for reproducing an image on a monitor screen using image data composed of a plurality of pixel data. Means, a range selecting means for selecting a specific range from images reproduced on the monitor screen, and an average for calculating an average value of luminance in the selected range using pixel data included in the selected range. Brightness calculation means, correction amount calculation means for calculating a correction amount for correcting the average value of the obtained brightness to a predetermined brightness value set in advance, and all pixel data using the obtained correction amount. It is characterized by comprising image data correcting means for correcting and image forming means for forming an image using the corrected image data.

According to a second image forming apparatus of the present invention, a color specifying means for specifying a color of a pixel from each pixel data included in image data composed of a plurality of pixel data, A pixel data extracting means for determining whether or not a predetermined color is included in pixel data, and extracting pixel data having a predetermined color, and an average for obtaining an average value of luminance using all the extracted pixel data. Brightness calculation means, correction amount calculation means for calculating a correction amount for correcting the average value of the obtained brightness to a predetermined brightness value set in advance, and all pixel data using the obtained correction amount. It is characterized by comprising image data correcting means for correcting and image forming means for forming an image using the corrected image data.

[0007] A third image forming apparatus of the present invention corresponds to each area when an image formed by using a plurality of pixel data is divided into a plurality of areas using the image data. Data dividing means for dividing the image data into a plurality of groups, and specifying the color of the pixel from each pixel data included in a group corresponding to one or more areas selected in advance among the divided areas. A color specifying unit that specifies a color shared by the most pixels among the pixels included in the group as a color of the group or a region corresponding to the group, and a color set in advance as a color of each specified region. A color comparing means for comparing the color with a predetermined color, and, when the color of each of the areas includes the predetermined color, the luminance of the area using pixel data included in the area. Using an average luminance calculating means for calculating an average value, a correction amount calculating means for calculating a correction amount for correcting the average value of the obtained luminance to a predetermined luminance value set in advance, and using the obtained correction amount. And an image forming means for forming an image using the corrected image data.

In each of the above structures, it is preferable that the correction amount is a value obtained by multiplying a difference between the predetermined luminance value and the average luminance value by a predetermined coefficient.

Further, it is preferable that the predetermined color is a color relating to human skin.

According to a first image data processing method of the present invention, there is provided an image reproducing step of reproducing an image on a monitor screen using image data composed of a plurality of pixel data, and an image reproducing step of reproducing the image reproduced on the monitor screen. A range selection step of selecting a specific range, an average brightness calculation step of calculating an average brightness value of the selected range using pixel data included in the selected range, and an average brightness value obtained A correction amount calculation step of calculating a correction amount for correcting the pixel value to a predetermined luminance value set in advance, an image data correction step of correcting all pixel data using the obtained correction amount, and a corrected image Outputting a corrected image data for outputting data.

According to a second image data processing method of the present invention, a color specifying step of specifying a color of a pixel from each pixel data included in image data composed of a plurality of pixel data; A step of extracting pixel data having a predetermined color by determining whether or not a predetermined color is included in the colors; and obtaining an average value of luminance using all the extracted pixel data. An average brightness calculation step, a correction amount calculation step of calculating a correction amount for correcting the calculated average brightness value to a predetermined brightness value, and all pixel data using the obtained correction amount. , And a corrected image data output step of outputting the corrected image data.

According to a third image data processing method of the present invention, an image data composed of a plurality of pixel data corresponds to each area when an image formed using the image data is divided into a plurality of areas. Dividing image data into a plurality of groups so that
The color of the pixel is specified from each pixel data included in the group corresponding to one or more regions selected in advance, and the color shared by the largest number of pixels among the pixels included in the group is specified by the group or A color specifying step of specifying the color of the region corresponding to the group; a color comparing step of comparing the specified color of each region with a predetermined color set in advance; When a predetermined color is included, an average luminance calculation step of calculating an average value of the luminance of the area using the pixel data included in the area, and calculating the average value of the obtained luminance by a predetermined predetermined A correction amount calculating step of calculating a correction amount for correcting to a luminance value by calculation; an image data correcting step of correcting all pixel data using the obtained correction amount; Characterized by comprising a correction image data output step of outputting the image data.

In each of the above methods, it is preferable that the correction amount is a value obtained by multiplying a difference between the predetermined luminance value and the average luminance value by a predetermined coefficient.

Further, it is preferable that the predetermined color is a color relating to human skin.

[0015] A recording medium on which the first image data processing program of the present invention is recorded includes an image reproducing process for reproducing an image on a monitor screen using image data composed of a plurality of pixel data; A range selection process of selecting a specific range from among the reproduced images; and an average brightness calculation process of calculating an average value of the brightness of the selected range using pixel data included in the selected range. A correction amount calculation process for calculating a correction amount for correcting the average value of the obtained brightness to a predetermined brightness value set in advance, and an image data correction process for correcting all pixel data using the obtained correction amount. And a corrected image data output process of outputting the corrected image data.

The recording medium on which the second image data processing program of the present invention is recorded includes a color specifying process for specifying the color of a pixel from each pixel data included in the image data composed of a plurality of pixel data, A pixel data extraction process of determining whether a predetermined color is included in the color of each of the extracted pixels and extracting pixel data having a predetermined color, and a luminance of the pixel data using all the extracted pixel data. Average brightness calculating means for calculating an average value of the correction value; a correction amount calculation process for calculating a correction amount for correcting the average value of the obtained brightness to a predetermined brightness value set in advance; Image data correction processing for correcting all pixel data using
The corrected image data output process for outputting the corrected image data is recorded so as to be executed by a computer.

According to a third aspect of the present invention, there is provided a recording medium on which a third image data processing program is recorded, wherein an image formed by a plurality of pixel data is divided into a plurality of areas formed by using the image data. Image data dividing processing for dividing the image data into a plurality of groups so as to correspond to the respective areas, and from the pixel data included in the group corresponding to one or two or more areas selected in advance among the divided areas. A color specifying process of specifying the color of the pixel and specifying a color shared by the most pixels among the pixels included in the group as a color of the group or a region corresponding to the group; A color comparison process of comparing a color with a predetermined color set in advance; and, when the color of each area includes the predetermined color, an image included in the area. Average luminance calculation processing for calculating the average value of the luminance of the area using the data, and correction amount calculation processing for calculating the correction amount for correcting the calculated average luminance value to a predetermined luminance value And an image data correction process of correcting all pixel data using the obtained correction amount, and a corrected image data output process of outputting corrected image data.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A first embodiment of the present invention will be described using a digital printer as an example. FIG. 1 shows an external configuration of a digital printer (digital photographic processing apparatus) according to the present embodiment. The same applies to the later-described second and third embodiments.

A digital printer prints an image captured by a digital camera directly on a piece of photographic paper,
The image formed on the silver halide film is once read by a scanner and printed on a piece of photographic paper. As shown in FIG. 1, a digital printer uses R (red), G (green), B (blue), or Y (red) to define a minute area on photographic paper corresponding to each pixel of an image sensor of a digital camera or scanner.
An image forming unit 100 that forms an image by exposing to light of any of the three primary colors (yellow), M (magenta), and C (cyan), and developing the exposed photographic paper; An image data processing unit 200 performs predetermined processing on data and outputs the processed data to the image forming unit 100.

The image forming section 100 includes magazines 101 and 102 in which plural types (for example, two types) of long photographic papers having different widths are wound and stored, and the magazines 101 and 102 are stored.
The photographic paper pulled out of the photographic paper is cut into a predetermined size, the exposing unit 103 exposing the image transmitted from the image data processing unit 200 on the cut photographic paper piece, and the exposed photographic paper piece is developed, bleached, fixed and stabilized. Development processing unit 104
And a drying section 105 for drying the developed photographic paper pieces, and a sorter section 106 for sorting the dried photographic paper pieces into, for example, a film unit. The image forming unit 10
Reference numeral 0 does not include a light source, a lens, a shutter, and the like for enlarging and exposing an image on a film on a piece of photographic paper in a conventional analog photographic processing apparatus.

The image data processing section 200 reads image data recorded on a recording medium such as a memory card or a CD-R, or reads / records image data after correction on these recording media. Device 20
1, a scanner 202 for directly reading an image formed on a film or photographic paper, a display 203 for displaying the read image on a monitor, and a keyboard 20 for inputting instructions for predetermined image processing and print processing.
And a control circuit (not shown) for performing predetermined processing on image data to be printed, converting the data into control data for controlling an exposure unit, and outputting the control data to the image forming unit 100. Further, the image data may be directly transmitted / received to / from another device via a modem, a LAN board, a communication line, or the like.

Next, FIG. 2 shows a block configuration for explaining the functions of the digital printer of the first embodiment.

The image data input section 210 is composed of, for example, an input / output interface, a CPU, a ROM, a RAM, etc., and takes in digital image data output from the data recording / reading device 201 or the scanner 202, and
Store and save it temporarily. Here, the digital image data is the R value from each pixel of an image sensor such as a digital camera or a scanner that has captured the image data.
An output signal (RGB data) relating to luminance for each of the color components (red), G (green) and B (blue) is serially arranged, and is serially input / output via an interface.

The image reproducing section 211 is provided on the display 20.
3. Reproduce a pre-scan image on the monitor screen of the display 203 using the input image data, which is constituted by a CPU, a ROM, a RAM, and the like.

The range selection section 212 is composed of a mouse, a keyboard 204, a CPU, a ROM, a RAM, and the like. Of the pre-scan images reproduced on the display 203, the operator or the user selects a main subject (for example, the face of a person). Part) is identified.

The average luminance calculation unit 213 includes a CPU, an RO,
M, RAM, etc., performs predetermined processing on input image data, particularly image data included in the range selected by the range selection unit 212, and calculates the brightness corresponding to each pixel. A histogram is created, and an average value of luminance in the selected range is calculated. The RGB data is information on color and luminance (brightness).
The B data is subjected to the arithmetic processing shown in Equation 1 below, and YCC data (C2, YY, C
Convert to 1). YY represents luminance information, C1 and C2
Represents color difference information. By this conversion, only information relating to luminance can be extracted from the RGB data.

[0027]

(Equation 1)

The correction amount calculation unit 214 includes a CPU, a ROM,
Comparing the calculated average value of the luminance of the main subject portion with a predetermined luminance value corresponding to a preset proper luminance, the main subject portion is made to have proper luminance (appropriate density). In addition, a correction amount necessary for matching the average value of the luminance with a predetermined luminance value is calculated,
And memorize it.

The image data correction unit 215 includes a CPU, an RO,
M, RAM, etc., and luminance (RGB data) of image data for all pixels using the calculated correction amount
Is corrected.

The corrected image data output unit 216 has an input / output interface and a CP as in the image data input unit 210.
U, ROM, RAM, etc.
And outputs the corrected image data.

The image forming section 100 forms an image on photographic paper using the corrected image data. The above CP
U, ROM, and RAM may be the same as each other, or may be different depending on the configuration of each unit.

Next, flowcharts of image data processing in the first embodiment are shown in FIGS. First, when the image data is read by the image data input unit 200 (step S1), the image reproduction unit 211 reads the image data from the RAM of the image data input unit 210 and displays the pre-scan image on the display 203 (step S1). S3). In this state, the user or the operator determines whether or not luminance correction is necessary for the displayed pre-scanned image (step S5). When luminance correction is not required, the user or operator proceeds to step S1 using a mouse or a keyboard. Return and display the next prescan image.

On the other hand, when the luminance correction is required, the pre-scan image displayed on the display 203 is displayed using the mouse and the keyboard of the range selection unit 212.
The main subject area is selected by the user or the operator in a range that is recognized as the main subject, for example, a face portion of a person (step S7).

When the main subject area is selected, the average luminance calculation section 213 reads out image data included in the selected range from the RAM of the image data input section 210 (step S9), and calculates each pixel according to the above equation (1). The luminance information YY for each is extracted (step S11). Further, a luminance histogram of each pixel included in the selected range is created (step S13), and an average value of the luminance in the selected range is calculated (step S15).

The correction amount calculation unit 214 compares the calculated average value of the brightness with a predetermined brightness value corresponding to a preset appropriate brightness and calculates a brightness correction amount (step S17). When the luminance correction amount is calculated, the luminance correction amount is stored in a RAM or the like of the image data input unit 210 together with, for example, a film frame number for specifying the image data (step S19).

When the luminance correction amount is stored, the image reproducing unit 21
1 determines whether or not a pre-scan image has been displayed on the display 203 for all image data stored in the RAM of the image data input unit 210 (step S21). Repeats steps S1 to S21.

When the pre-scan is completed for all the image data (YES in step S21), the image data correction unit 215 sequentially reads out each image data and the luminance correction amount for the image data (step S23), and sets the luminance correction amount. (Step S2)
5) The corrected image data is stored in a RAM or the like (step S27). Further, the image data correction unit 215
It is determined whether or not the brightness correction has been performed for all the image data to be subjected to the brightness correction (step S29),
If the correction has not been completed, steps S23 to S29
repeat.

When the correction of all the image data is completed, the corrected image data output unit 216 determines whether or not to output the corrected image data to the image forming unit 100 (Step S31). That is, when an image is formed using the corrected image data, the corrected image data output unit 216 outputs the corrected image data to the image forming unit 100 (Step S33). Then, the image forming unit 100 forms an image on the printing paper piece using the corrected image data output from the image data processing unit 200 (step S35), and ends this flow.

Next, the effect of correcting image data according to the first embodiment will be described with reference to FIG. An image captured by a digital camera or the like is shown in FIG.
As shown in (b), it is assumed that the scene is a “backlit scene” in which the luminance of the background is high (the density is low and bright) and the luminance of the main subject is low (the density is high and dark).

When an image is formed by using this image data without correction, an image of a backlight scene is obtained as shown in FIG. On the other hand, according to Evans's theorem, R
When the RGB color components are corrected so that the color of all the image data for each of the GBs becomes gray when the colors are averaged, FIG.
As shown in (c), the background is darkened so as to become gray, and the person who is the main subject having originally low luminance (high density and dark) is further darkened, and the details thereof are almost completely lost.

On the other hand, when the main subject portion is extracted and all the image data is corrected so that the luminance (density) of the main subject portion becomes appropriate as in the present embodiment, FIG. As shown in (1), the background having originally high luminance (low density and bright) is corrected to be brighter, but the person who is the main subject is corrected to proper luminance (proper density) so that its details can be clearly distinguished. . As a result, appropriate correction can be performed even for an image having a bias in density such as a backlight scene. Note that, contrary to the example shown in FIG. 5, as in the case of flash photography in a dark place,
Even when the luminance of the main subject is high and the luminance of the background is low, appropriate correction can be similarly performed.

Second Embodiment Next, a second embodiment of the present invention will be described. In the first embodiment, the pre-scanned image is temporarily displayed on the display 203 using the input image data, and the user or the operator specifies the range of the main subject to be subjected to the luminance correction. In the second embodiment,
The color information of the image data is analyzed, and the part considered to be the main subject is automatically recognized using the color information.

FIG. 6 is a block diagram for explaining the functions of the digital printer according to the second embodiment.

The image data input unit 220 is, for example, an input / output interface, a CP, as in the first embodiment.
A digital image data output from the data recording / reading device 201 or the scanner 202 is fetched and temporarily stored and stored in the RAM or the like.

The color specifying unit 221 includes a CPU, ROM, RA
M and the like, and performs predetermined processing on the input image data to specify a color of a portion corresponding to each pixel (hereinafter, simply referred to as “pixel color”). The above RGB
The data is information on color and luminance (brightness).
The arithmetic processing shown in the above equation 1 is performed on the GB data, and YCC data (C2, YY, C
Convert to 1). By this conversion, only the information regarding the color can be extracted from the RGB data.

FIG. 7 shows color information two-dimensionally, with C1 as the vertical axis and C2 as the horizontal axis. The hatched area in FIG. 7 represents the average range of Japanese skin color when a person is photographed as a main subject.

The pixel data extraction unit 222 includes a CPU, an RO
M, RAM, etc., and compares the color of each pixel specified by the color specifying unit 221 with a predetermined color representing a main subject, such as the skin color of a person, which is set in advance. Then, all image data corresponding to pixels having a predetermined color or a color included in a predetermined range is extracted and stored in a RAM or the like. Specifically, C1 and C2 calculated by the color specifying unit 221 for all the pixels
LUT stored in ROM or the like in advance
(Lookup table), C1 and C2
It is determined whether or not the value is equal to the predetermined value or is included in a predetermined range. Thereby, image data relating to the main subject is extracted from all the pixel data.

The average luminance calculation unit 223 includes a CPU, an RO,
An average luminance value of a portion corresponding to the main subject is calculated by using all the extracted image data, which is composed of M, RAM, and the like. In the present embodiment, the main subject in the image is
The purpose is to correct the brightness (density) without being affected by the brightness of other parts such as the background,
Through the above-described processes, luminance information of only the main subject portion can be obtained.

The correction amount calculation unit 224 includes a CPU, a ROM,
Comparing the calculated average value of the luminance of the main subject portion with a predetermined luminance value corresponding to a preset proper luminance, the main subject portion is made to have proper luminance (appropriate density). In addition, a correction amount necessary for matching the average value of the luminance with a predetermined luminance value is calculated,
And memorize it.

The image data correction unit 225 includes a CPU, an RO,
M, RAM, etc., and luminance (RGB data) of image data for all pixels using the calculated correction amount
Is corrected.

The corrected image data output unit 226 has an input / output interface and a CP as in the image data input unit 220.
U, ROM, RAM, etc.
And outputs the corrected image data.

Next, flowcharts of image data processing in the second embodiment are shown in FIGS. In the second embodiment, first, color information for specifying the main subject area,
For example, the skin color of a person is selected and set from a color chart or the like displayed on a display using a mouse, a keyboard, or the like (step S51).

When the image data is read by the image data input unit 220 (step S53), the color specifying unit 221 is used.
Reads out the image data from the RAM of the image data input unit 210 and calculates the color information C1
And C2 are extracted (step S55), and the color of the pixel is specified for each pixel. Then, the pixel data extraction unit 22
2 compares the specified color of each pixel with the color of the main subject set in step S51 (step S57), and extracts only pixel data or luminance information YY of a pixel having the same color as the color of the main subject. Is stored in a RAM or the like (step S59). Further, the color specifying unit 221 or the pixel data extracting unit 222 specifies the pixel colors for all the pixels,
It is determined whether the comparison and the extraction of the pixel data have been completed (step S61), and the above steps S55 to S61 are repeated until the comparison is completed for all the pixels.

When the specification and comparison of the pixel colors and the extraction of the pixel data have been completed for all the pixels, the average luminance calculating section 2
23 creates a luminance histogram of all pixels having the same color as the color of the main subject using the pixel data or luminance information YY extracted in step S59, and calculates an average luminance value (step S63).

The correction amount calculating section 224 compares the calculated average value of the luminance with a predetermined luminance value corresponding to a preset appropriate luminance, and calculates the luminance correction amount (step S65). When the luminance correction amount is calculated, the luminance correction amount is stored in a RAM or the like of the image data input unit 210 together with, for example, a frame number of the film for specifying the image data (step S67).

When the luminance correction amount is stored, for example, the correction amount calculation unit 224 determines whether or not the luminance correction amount has been calculated for all the image data (step S69). If not completed, steps S53 to S69 are repeated.

When the luminance correction amount is calculated for all the image data (YES in step S69), the image data correction unit 225 sequentially reads out the image data and the luminance correction amount for the image data (step S71), and Is used to correct each image data (step S7).
3) The corrected image data is stored in a RAM or the like (step S75). Further, the image data correction unit 225
It is determined whether or not the luminance correction has been performed for all the image data to be subjected to the luminance correction (step S77).
If the correction has not been completed, steps S71 to S77
repeat.

When the correction of all the image data is completed, the corrected image data output section 226 determines whether or not to output the corrected image data to the image forming section 100 (Step S79). That is, when an image is formed using the corrected image data, the corrected image data output unit 226 outputs the corrected image data to the image forming unit 100 (Step S81). Then, the image forming section 100 forms an image on the photographic paper piece using the corrected image data output from the image data processing section 200 (step S83), and ends this flow.

Third Embodiment Next, a third embodiment of the present invention will be described. In the second embodiment, the color of each pixel is specified using all the pixel data in the image data, and the average of the luminance is determined using the pixel data of the pixel having the same color as the color of the preset main subject. In the third embodiment, the image is divided into a plurality of regions, and one or two or more regions selected in advance, for example, in the center of the screen, are calculated. Using the pixel data of the partial area to be analyzed, the color information of the image data is analyzed, the average value of the luminance is calculated, and the luminance correction amount is calculated.

FIG. 10 is a block diagram illustrating the function of the digital printer according to the third embodiment.

The image data input unit 230 is provided with the first and second
As in the case of the embodiment, for example, an input / output interface, a CPU, a ROM, a RAM, and the like are configured. save.

The image data dividing section 231 is composed of a CPU, an RO
M, RAM, etc., and assuming that an image is formed by using any of the captured image data, the image data is divided into pixels so as to correspond to each area obtained by dividing the image into a plurality of areas. Divided into a plurality of groups according to the address or the like.

The color specifying section 232 includes a CPU, ROM, RA
M, and is included in a group corresponding to one or more regions selected in advance, for example, a plurality of regions near the center of the screen, among the regions divided by the image data dividing unit 231. Using pixel data,
The arithmetic processing shown in Equation 1 above is performed on the RGB data,
YCC data (C2, YY,
C1). By this conversion, only the information regarding the color is extracted from the RGB data, and the color of each pixel is specified.
Further, the color shared by the largest number of pixels among the pixels included in the group is specified as the color of the group or a region corresponding to the group.

The color comparison unit 233 includes a CPU, ROM, RA
M, etc., and compares the color of each area specified by the color specifying unit 232 with a predetermined color set in advance, for example, the color of the main subject arbitrarily set by the user or the operator, such as the color of the skin of a person. Then, it is determined whether or not a predetermined color is included in the color of each area.

The average luminance calculation section 234 includes a CPU, an RO,
M, RAM, etc., and when the color comparing unit 233 determines that a predetermined color is included in the color of each area, the average value of the luminance of the area is determined using the pixel data of the area. Is calculated. In the present embodiment, since the brightness correction processing is performed using only the image data of the part where the possibility that the main subject is likely to be present is high, the number of data to be processed is reduced, and the time required for the arithmetic processing is reduced. Becomes possible.

The correction amount calculation unit 235 includes a CPU, a ROM,
Comparing the calculated average value of the luminance of the main subject portion with a predetermined luminance value corresponding to a preset proper luminance, the main subject portion is made to have proper luminance (appropriate density). In addition, a correction amount necessary for matching the average value of the luminance with a predetermined luminance value is calculated,
And memorize it.

The image data correction unit 236 includes a CPU, an RO,
M, RAM, etc., and luminance (RGB data) of image data for all pixels using the calculated correction amount
Is corrected.

The corrected image data output unit 237 has an input / output interface
U, ROM, RAM, etc.
And outputs the corrected image data.

Next, FIGS. 11 to 12 show flowcharts of image data processing in the third embodiment.

When the image data is read by the image data input unit 230 (step S101), the image data dividing unit 231 assumes that the image data is formed using the image data as shown in FIG. The image is divided into a plurality of pieces (for example, 5 × 5 = 25) in the vertical direction and the horizontal direction (step S103), and the image data is divided into a plurality of groups according to the addresses of the pixels and the like so as to correspond to the respective divided areas. To divide.

The color specifying section 232 is provided for the image data dividing section 23.
The pixel data of a group corresponding to one or two or more areas selected in advance among the areas divided by 1 is read from the RAM of the image data input unit 210 (step S105), and each pixel is read according to the above equation (1). The color information C1 and C2 are extracted (step S107), and the color of the pixel is specified for each pixel. Further, a histogram or the like is created for each color of the pixel, and the color shared by the largest number of pixels among the pixels included in the area or the group is specified as the color of the group or the area corresponding to the group (step S109). .

Next, the color comparing section 233 compares the specified color of each area with a preset color of the main subject (step S111), and determines that an area having the same color as the main subject color is present. It is determined whether or not there is (step S1
13). When there is a region having the same color as the color of the main subject, the average luminance calculation unit 234 creates a histogram of the luminance of all the pixels included in the region using the pixel data or the luminance information YY of the region, and generates the luminance. Is calculated (step S115). If there is no area having the same color as the color of the main subject (NO in step S113),
Proceeding to step S121, the luminance of the next image data is corrected.

The correction amount calculating section 235 compares the calculated average value of the luminance with a predetermined luminance value corresponding to a preset appropriate luminance, and calculates the luminance correction amount (step S117). When the brightness correction amount is calculated, the brightness correction amount is stored in the RAM of the image data input unit 230 together with, for example, the frame number of the film for specifying the image data.
And the like (step S119).

When the brightness correction amount is stored, for example, the correction amount calculation unit 235 determines whether or not the brightness correction amount has been calculated for all the image data (step S121). If not completed, steps S101 to S121 are repeated.

When the luminance correction amount is calculated for all the image data (YES in step S121), the image data correction unit 236 sequentially reads out the image data and the luminance correction amount for the image data (step S123), Is used to correct each image data (step S1).
25) The corrected image data is stored in a RAM or the like (step S127). Further, the image data correction unit 23
6 judges whether or not the luminance correction has been performed for all the image data to be subjected to the luminance correction (step S1).
29) If the correction is not completed, step S123
To S129 are repeated.

When the correction of all the image data is completed, the corrected image data output section 237 determines whether or not to output the corrected image data to the image forming section 100 (Step S131). That is, when an image is formed using the corrected image data, the corrected image data output unit 237 outputs the corrected image data to the image forming unit 100 (Step S133). Then, the image forming unit 100 forms an image on a piece of photographic paper using the corrected image data output from the image data processing unit 200 (Step S13).
5), end this flow.

Other Embodiments In the above embodiments, the main subject region is specified, and the luminance correction amount is determined so that the average value of the luminance of the main subject region becomes a predetermined luminance value corresponding to the appropriate luminance. However, the present invention is not limited to this, and a predetermined coefficient (for example, 6
A value multiplied by an arbitrary value between 0 and 80%) may be used as the luminance correction amount. That is, as shown in FIG. 7, even if the main subject color is a person's skin color as an example, the main subject color may have a certain color range instead of a single color. If the luminance is corrected only for an area having (for example, the skin color of a person), the correction is excessive for the area of another color similar to that color, and the image quality after correction may be reduced. . Also, if the brightness of the main subject before correction is extremely high or low relative to the proper brightness, and the brightness of the main subject area is completely corrected to the proper brightness, the brightness of the parts other than the main subject will be abnormal. May be lower or higher. Therefore, in these cases, it is preferable that the luminance of the main subject region is not completely corrected to the proper luminance, but is corrected to a degree close to the proper luminance. Furthermore, in each of the above embodiments, the color of the main subject area is treated as a single color, but is not limited thereto, and may be a plurality of colors included in a predetermined range.

In the first embodiment, the image before correction is displayed as a pre-scan image on the monitor screen of the display 203. However, the image for printing is further formed by using the image data after correction. Display 2
03 may be displayed on the monitor screen. Furthermore, when displaying a pre-scan image on the monitor screen of the display 203 and when calculating the luminance correction amount of the main subject area, the number of pixels of the image data may be reduced and used.
The latter is the same for the second and third embodiments.

Further, in each of the above embodiments, a digital printer has been described as an example of an image forming apparatus. However, the present invention is not limited to this, and a personal computer and a color printer connected thereto, such as a thermal transfer type color printer, An inkjet color printer, a laser color printer, or the like may be used.

Further, the present invention is not limited to the image forming apparatus, but also includes an image data correction method executed by a personal computer and a recording medium storing a program for executing the method.

[0081]

As described above, according to the first image forming apparatus of the present invention, an image reproducing means for reproducing an image on a monitor screen using image data composed of a plurality of pixel data, Range selection means for selecting a specific range from the images reproduced on the monitor screen, and average brightness calculation means for calculating an average value of the brightness of the selected range using pixel data included in the selected range Correction amount calculating means for calculating a correction amount for correcting the average value of the obtained luminance to a predetermined luminance value set in advance, and an image for correcting all pixel data using the obtained correction amount The image processing apparatus includes a data correcting unit and an image forming unit that forms an image using the corrected image data.

According to the first image data processing method of the present invention, an image reproducing step of reproducing an image on a monitor screen using image data composed of a plurality of pixel data, A range selection step of selecting a specific range from the selected image, and an average brightness calculation step of calculating an average value of brightness in the selected range using pixel data included in the selected range. A correction amount calculation step of calculating a correction amount for correcting the average value of the brightness to a predetermined brightness value set in advance, and an image data correction step of correcting all pixel data using the obtained correction amount, Outputting corrected image data.

Further, according to the recording medium on which the first image data processing program of the present invention is recorded, an image reproducing process for reproducing an image on a monitor screen by using image data composed of a plurality of pixel data; Range selection processing for selecting a specific range from images reproduced on the monitor screen, and average luminance calculation processing for calculating an average value of luminance in the selected range using pixel data included in the selected range And a correction amount calculating process for calculating a correction amount for correcting the average value of the obtained luminance to a predetermined luminance value set in advance, and an image for correcting all pixel data using the obtained correction amount The data is recorded so that the computer executes a data correction process and a corrected image data output process for outputting corrected image data.

That is, according to these inventions, the user or the operator recognizes that the main subject is the main subject, and uses the pixel data of the specified range on the monitor screen so that the brightness of the specified range becomes appropriate. Since the entire image data is corrected, it is possible to obtain an image in which the face portion of a person who is the main subject on the screen is corrected to an appropriate brightness (density) even in a backlight scene or flash photography, for example. it can. Further, since the range of the main subject of the image is specified by the user or the operator, the number of pixel data used for luminance correction can be reduced, and the time required for calculating the luminance correction amount can be shortened.

According to the second image forming apparatus of the present invention, the color specifying means for specifying the color of a pixel from each pixel data included in the image data composed of a plurality of pixel data is specified. A pixel data extracting means for determining whether a predetermined color is included in the color of each pixel and extracting pixel data having a predetermined color, and averaging the luminance using all the extracted pixel data; Average brightness calculating means for obtaining a value;
Correction amount calculating means for calculating a correction amount for correcting the average value of the obtained luminance to a predetermined luminance value set in advance, and image data correction for correcting all pixel data using the obtained correction amount Means and an image forming means for forming an image using the corrected image data.

Further, according to the second image data processing method of the present invention, a color specifying step of specifying a color of a pixel from each pixel data included in image data composed of a plurality of pixel data is specified. A pixel data extraction step of determining whether a predetermined color is included in the colors of the respective pixels and extracting pixel data having the predetermined color; and An average brightness calculating step for calculating an average value, a correction amount calculating step for calculating a correction amount for correcting the calculated average value of the brightness to a predetermined brightness value, and a correction amount calculating step. And a corrected image data output step of outputting corrected image data.

Further, according to the recording medium on which the second image data processing program of the present invention is recorded, the color identification for identifying the color of each pixel from each pixel data included in the image data composed of a plurality of pixel data Processing, determine whether a predetermined color is included in the color of each specified pixel,
A pixel data extraction process for extracting pixel data having a predetermined color, an average luminance calculating means for calculating an average value of the luminance using all the extracted pixel data, and an average value of the obtained luminance are preset. A correction amount calculation process for calculating a correction amount for correcting to a predetermined luminance value, an image data correction process for correcting all pixel data using the obtained correction amount, and a correction for outputting corrected image data The image data output processing is recorded so as to be executed by a computer.

That is, according to these inventions, the brightness of the image data is automatically corrected without displaying the image on the monitor screen once. Therefore, the number of pixel data used for calculating the brightness correction amount for each image data Is larger than in the first case, but it is not necessary to display each image on the monitor screen. For example, when a plurality of image data are recorded on one recording medium and all the images are printed, Then, it is possible to shorten the total processing time.

Further, according to the third image forming apparatus of the present invention, each image data composed of a plurality of pixel data is divided into a plurality of regions when an image formed by using the image data is divided into a plurality of regions. Image data dividing means for dividing the image data into a plurality of groups so as to correspond to the regions; and, from among the divided regions, the pixel data from the pixel data included in the group corresponding to one or more regions selected in advance. Color specifying means for specifying the color shared by the largest number of pixels among the pixels included in the group as the color of the group or the area corresponding to the group, and the color of each specified area. A color comparing unit that compares the predetermined color with a predetermined color set in advance, and using the pixel data included in the area when the color is included in the color of each area. Average luminance calculating means for calculating an average value of the luminance of the region, and correction amount calculating means for calculating a correction amount for correcting the calculated average value of the luminance to a predetermined luminance value. Image data correcting means for correcting all pixel data using the corrected correction amount, and image forming means for forming an image using the corrected image data.

Further, according to the third image data processing method of the present invention, the image data composed of a plurality of pixel data is divided into a plurality of areas formed by using the image data. An image data dividing step of dividing the image data into a plurality of groups so as to correspond to the respective regions; and, from among the divided regions, each pixel data included in a group corresponding to one or more regions selected in advance. A color specifying step of specifying the color of the pixel, and specifying the color shared by the largest number of pixels among the pixels included in the group as the color of the group or the area corresponding to the group; and the color of each specified area. A color comparison step of comparing the image with a predetermined color set in advance; and, when the color of the area includes the predetermined color, an image included in the area. An average luminance calculating step of calculating an average value of the luminance of the region using the data, and a correction amount calculating step of calculating a correction amount for correcting the obtained average value of the luminance to a predetermined luminance value And an image data correction step of correcting all pixel data using the obtained correction amount, and a corrected image data output step of outputting corrected image data.

Further, according to the recording medium on which the third image data processing program of the present invention is recorded, image data composed of a plurality of pixel data is converted into an image formed using the image data in a plurality of areas. Image data division processing for dividing the image data into a plurality of groups so as to correspond to the respective areas when the image data is divided into a plurality of areas, and among the divided areas, the image data is included in a group corresponding to one or more areas selected in advance A color specifying process of specifying a color of the pixel from each pixel data and specifying a color shared by the most pixels among the pixels included in the group as a color of the group or a region corresponding to the group; A color comparison process for comparing the color of each area with a predetermined color set in advance; and, when the color of each area includes the predetermined color, the area And an average brightness calculation process for calculating an average value of the brightness of the area using the pixel data included in the image data, and a correction amount for correcting the obtained average value of the brightness to a predetermined brightness value by calculation. A correction amount calculation process, an image data correction process of correcting all pixel data using the obtained correction amount, and a corrected image data output process of outputting corrected image data are recorded to be executed by a computer. I have.

That is, according to these inventions, as in the second case, the brightness correction of the image data is automatically performed without displaying the image on the monitor screen once, so that the total processing time can be shortened. It is possible to Also,
Assuming that the image was formed using the image data,
The image is divided into a plurality of regions, and the user or operator selects one or more regions in which the main subject is likely to be present, and uses only the pixel data included in the selected region to obtain a luminance. Since the correction is performed, the number of pixel data used for calculating the luminance correction amount can be extremely reduced, and the time required for calculating the luminance correction amount can be shortened.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an external configuration of a digital printer according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a block configuration of a digital printer according to the first embodiment of the present invention.

FIG. 3 is a flowchart of image data processing according to the first embodiment.

FIG. 4 is a continuation of the flowchart in FIG. 3;

FIG. 5 is a diagram for explaining an effect of luminance correction of image data according to the present invention.

FIG. 6 is a diagram illustrating a block configuration of a digital printer according to a second embodiment of the present invention.

FIG. 7 is a diagram showing color information two-dimensionally.

FIG. 8 is a flowchart of image data processing according to the second embodiment.

FIG. 9 is a continuation of the flowchart in FIG. 8;

FIG. 10 is a diagram illustrating a block configuration of a digital printer according to a third embodiment of the present invention.

FIG. 11 is a flowchart of image data processing according to the third embodiment.

FIG. 12 is a continuation of the flowchart in FIG. 11;

FIG. 13 is a diagram showing a state in which a virtual image is divided into a plurality of regions in the third embodiment.

[Explanation of symbols]

 100: Image forming unit 200: Image data processing unit 210: Image data input unit 211: Image reproduction unit 212: Range selection unit 213: Average luminance calculation unit 214: Correction amount calculation unit 215: Image data correction unit 216: Corrected image data Output unit 220: Image data input unit 221: Color identification unit 222: Pixel data extraction unit 223: Average luminance calculation unit 224: Correction amount calculation unit 225: Image data correction unit 226: Corrected image data output unit 230: Image data input unit 231: Image data division unit 232: Color specification unit 233: Color comparison unit 234: Average luminance calculation unit 235: Correction amount calculation unit 236: Image data correction unit 237: Corrected image data output unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G06T 5/00 100 B41J 3/00 B 5C077 H04N 1/60 H04N 1/40 D 5C079 1/407 101E 1 / 46 1/46 Z F term (reference) 2C262 AA24 AB11 BA09 BA16 BC10 EA08 FA14 GA23 2H106 AA51 AA76 AA80 AA85 AB04 BA22 BA27 BA58 2H110 BA07 BA17 BA18 CB27 CB31 CB33 CB36 5B057 AA11 BA02 BA24 BA25 CA01 CB03 CA12 CB33 CE17 CE18 CH08 DA16 DA17 DC23 5C076 AA27 AA36 AA40 BA06 CA02 CA10 5C077 LL01 MP08 PP15 PP32 PP33 PP34 PP38 PP46 PQ08 PQ19 SS05 SS07 TT02 5C079 HB01 HB02 HB04 HB12 LA02 LA10 LA12 LA31 LA39 LB12 MA11 MA17

Claims (13)

[Claims] 1. An image reproducing means for reproducing an image on a monitor screen by using image data composed of a plurality of pixel data, and a range selecting means for selecting a specific range from the images reproduced on the monitor screen. Average luminance calculating means for calculating an average value of the luminance of the selected range using the pixel data included in the selected range; and converting the calculated average value of the luminance to a predetermined luminance value set in advance. Correction amount calculation means for calculating a correction amount for correction by calculation, image data correction means for correcting all pixel data using the obtained correction amount, and image formation for forming an image using the corrected image data And an image forming apparatus. 2. A color specifying means for specifying a color of a pixel from each pixel data included in image data composed of a plurality of pixel data, and a predetermined color is included in the specified color of each pixel. Pixel data extraction means for judging whether or not the pixel data has a predetermined color, and an average brightness calculation means for obtaining an average value of the brightness using all the extracted pixel data; Correction amount calculating means for calculating a correction amount for correcting the average value of the pixels to a predetermined luminance value set in advance; image data correcting means for correcting all pixel data using the obtained correction amount; And an image forming means for forming an image using the obtained image data. 3. An image in which image data composed of a plurality of pixel data is divided into a plurality of groups so as to correspond to each region when an image formed using the image data is divided into a plurality of regions. A data division unit, and a pre-selected one of the divided areas
Alternatively, the color of the pixel is specified from each pixel data included in the group corresponding to two or more areas, and the color shared by the most pixels among the pixels included in the group is set to the group or the area corresponding to the group. A color specifying unit that specifies the color of each of the regions; a color comparing unit that compares the color of each of the specified regions with a predetermined color that is set in advance; and the color of each of the regions includes the predetermined color. Means for calculating an average value of the luminance of the area using the pixel data included in the area, and correcting the average value of the obtained luminance to a predetermined luminance value set in advance. Correction amount calculating means for calculating the correction amount of the image data, image data correcting means for correcting all pixel data using the obtained correction amount, and an image forming an image using the corrected image data. An image forming apparatus characterized by comprising a formation unit. 4. The apparatus according to claim 1, wherein the correction amount is a value obtained by multiplying a difference between the predetermined luminance value and the average luminance value by a predetermined coefficient. Image forming device. 5. The image forming apparatus according to claim 1, wherein the predetermined color is a color related to human skin. 6. An image reproducing step of reproducing an image on a monitor screen using image data composed of a plurality of pixel data, and a range selecting step of selecting a specific range from the images reproduced on the monitor screen. And an average brightness calculating step of calculating an average value of the brightness of the selected range using the pixel data included in the selected range; and converting the obtained average value of the brightness to a predetermined brightness value set in advance. A correction amount calculation step of calculating a correction amount for correction by calculation, an image data correction step of correcting all pixel data using the obtained correction amount, and a corrected image data output step of outputting corrected image data. An image data processing method comprising: 7. A color specifying step for specifying a color of a pixel from each pixel data included in image data composed of a plurality of pixel data, and a predetermined color is included in the specified color of each pixel. Pixel data extraction step of determining whether or not the pixel data has a predetermined color, and an average luminance calculation step of calculating an average value of the luminance using all the extracted pixel data; A correction amount calculating step for calculating a correction amount for correcting the average value of the pixels to a predetermined luminance value set in advance; an image data correcting step for correcting all pixel data using the obtained correction amount; And outputting a corrected image data. 8. An image in which image data composed of a plurality of pixel data is divided into a plurality of groups so as to correspond to respective regions when an image formed using the image data is divided into a plurality of regions. A data division step, and a pre-selected one of the divided areas
Alternatively, the color of the pixel is specified from each pixel data included in the group corresponding to two or more areas, and the color shared by the most pixels among the pixels included in the group is set to the group or the area corresponding to the group. A color identification step of identifying the color of each area; a color comparison step of comparing the identified color of each area with a predetermined color set in advance; and the predetermined color is included in the color of each area. The average brightness calculation step of calculating the average value of the brightness of the area using the pixel data included in the area, and correcting the calculated average value of the brightness to a predetermined brightness value. A correction amount calculation step of calculating the correction amount of the image data, an image data correction step of correcting all pixel data using the obtained correction amount, and outputting the corrected image data. Image data processing method characterized by comprising the corrected image data output step of. 9. The method according to claim 6, wherein the correction amount is a value obtained by multiplying a difference between the predetermined luminance value and the average value of the luminance by a predetermined coefficient. Image data processing method. 10. The image data processing method according to claim 6, wherein the predetermined color is a color related to human skin. 11. An image reproducing process for reproducing an image on a monitor screen using image data composed of a plurality of pixel data, and a range selecting process for selecting a specific range from the images reproduced on the monitor screen. And an average brightness calculation process of calculating an average value of the brightness of the selected range using the pixel data included in the selected range; and converting the obtained average value of the brightness to a predetermined brightness value set in advance. A correction amount calculation process for calculating a correction amount for correction by calculation, an image data correction process for correcting all pixel data using the obtained correction amount, and a corrected image data output process for outputting corrected image data. Recording medium storing an image data processing program for causing a computer to execute the program. 12. A color specifying process for specifying a color of a pixel from each pixel data included in image data composed of a plurality of pixel data, and a predetermined color is included in the specified color of each pixel. Pixel data extraction processing for determining whether or not the pixel data has a predetermined color, and an average luminance calculating means for calculating an average value of the luminance using all the extracted pixel data; Correction amount calculation processing for calculating a correction amount for correcting the average value of the pixels to a predetermined luminance value set in advance; image data correction processing for correcting all pixel data using the obtained correction amount; A recording medium storing an image data processing program for causing a computer to execute a corrected image data output process for outputting the output image data. 13. An image in which image data composed of a plurality of pixel data is divided into a plurality of groups so as to correspond to respective regions when an image formed using the image data is divided into a plurality of regions. The data division processing, and a pre-selected one of the divided areas
Alternatively, the color of the pixel is specified from each pixel data included in the group corresponding to two or more areas, and the color shared by the most pixels among the pixels included in the group is set to the group or the area corresponding to the group. A color specifying process for specifying the color of each region; a color comparing process for comparing the specified color of each region with a predetermined color set in advance; and the predetermined color is included in the color of each region. The average brightness calculation processing for calculating the average value of the brightness of the area using the pixel data included in the area, and correcting the calculated average value of the brightness to a predetermined brightness value set in advance. Correction amount calculation processing for calculating the correction amount of image data, image data correction processing for correcting all pixel data using the obtained correction amount, and correction image data for outputting corrected image data A recording medium recording the image data processing program for executing a force canceling the computer.