JP2006345094A - Image processor and processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a matter wherein, even if a user corrects the color tone of image data by means of a slide bar on the screen with the intention of comparable amount of correction on saturation and hue, variation in chromaticness is larger when the hue is altered and it does not agree with sensuous operation of the user. <P>SOLUTION: A reference color becoming a correction object on image data is specified by means of a syringe tool 330 and color difference for the reference color is specified by means of a color difference slide bar 310. Consequently, a specifiable range (maximum value/minimum value) is set for the slide bar 320, 321, 322 of each color tone parameter value of L, c, h for the reference color on the basis of CIE1994 color difference formula. Operation agreeing with sense of a user is performed by making color tone correction of the reference color using the slide bars 320, 321, 322. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image processing apparatus and method, and more particularly, to an image processing apparatus and method for correcting color tone of image data.

  In general, an image processing application installed in a computer is used to correct the color tone of image data.

In conventional image processing applications, various controls are prepared in advance as GUI (Graphical User Interface) components that make up the screen, such as a slide bar and numeric input box for color correction, and the user uses these controls. Color tone correction was performed (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 9-322006

  However, it cannot be said that the control in the conventional image processing application is created in consideration of human senses.

  For example, when the user changes the hue or saturation using a slide bar or the like on the screen to correct the color tone of the image data, the hue is set to be higher than the saturation even if the same amount of correction is intended. When the color was changed, the amount of change in the appearance of the color was larger, which was not consistent with the user's sensory operation.

  Also, as represented by the MacAdam ellipse, it is known that the amount of change for one scale, such as hue and saturation, differs depending on the color. However, since the conventional control does not consider such color characteristics, its operability is still different from human senses.

  The present invention has been made to solve the above-described problems, and provides an image processing apparatus and method for improving the operability by making the correction method of the color tone parameter for the image data closer to a human sense. With the goal.

  As a means for achieving the above object, an image processing apparatus of the present invention comprises the following arrangement.

  That is, a reference color designating unit for designating a reference color to be corrected in image data, a parameter designating unit for designating a tone parameter value of the reference color, and the reference color to be the designated tone parameter value An image processing apparatus comprising: a color correcting unit that corrects; and an image display unit that displays the image data using the corrected reference color, wherein the color difference specifying unit specifies a color difference with respect to the reference color; Correction range setting means for setting a specifiable range of tone parameter values in the parameter specifying means based on the color difference.

  For example, the correction range setting means sets the specifiable range of the tone parameter value based on a CIE1994 color difference formula.

  According to the present invention, it is possible to make the tone parameter correction method for image data closer to a human sense and improve operability.

  Hereinafter, the present invention will be described in detail based on preferred embodiments with reference to the accompanying drawings.

<First Embodiment>
Image Processing System FIG. 1 is a diagram showing a configuration of an image processing system that is an embodiment according to the present invention. The image processing system of this embodiment is configured by interconnecting a client PC 100 and a print server 200 via a LAN 300, and a printer 201 is connected to the printer server 200. In this system, an image captured using the digital camera 101 can be edited by the client PC 100 and printed out from the printer 201 via the LAN 300 and the print server 200.

  The client PC 100 and the printer server 200 are constituted by so-called PC / AT compatible computers, each of which includes a CPU, a RAM, a hard disk, a monitor, and the like.

  The client PC 100 is installed with an image processing application for performing image processing on image data input from the digital camera 101 or a hard disk. Using this image processing application, the user sets correction values for color tone correction and a layout on printing paper. The client PC 100 executes printing of image data by transferring image data, layout data, correction values, ICC profiles for printing, print instruction data for specifying the number of copies to be printed and pages, and the like to the print server 200.

  When these data are received from the client PC 100, the printer server 200 generates print data by applying color correction and layout specified for the image data. The print data is spooled in the printer server 200 as a print job and printed using the printer 201 as appropriate.

FIG. 2 is a block diagram showing a part of the functional configuration realized by the image processing application installed in the client PC 100.

  The main control unit 110 performs overall control of each functional block. The image data input unit 120 inputs image data from a hard disk in the PC 100, the digital camera 101, or the like. The correction value input unit 121 provides a GUI on the screen and obtains correction values for brightness, saturation, and hue of image data input by the user. The color tone correction unit 111 performs color tone correction on the image data based on the input correction value, and displays the result on the GUI. The corrected image output unit 130 outputs the image data subjected to the color tone correction to the printer 201, the hard disk in the PC 100, or the like.

GUI Configuration FIG. 3 is a diagram illustrating an example of a GUI provided by the correction value input unit 121. According to the figure, a color difference slide bar 310 is newly set in addition to general slide bars 320, 321, and 322 for adjusting brightness, saturation, hue, and the like.

  In the figure, a dropper tool 330 is used for designating a color as a reference when calculating a color difference by clicking a part of an image 350 after the selection. In general, the reference color is set to a subject (skin color, sky, etc.) that is most important for color tone correction in the image. The reference color set here is displayed in the preview 331.

  The lightness slide bar 320 is used to adjust the lightness (L value) of the image 350. The maximum value / minimum value that can be specified with the lightness slide bar 320 is calculated from the reference color set with the dropper tool 330 and the value set with the color difference slide bar 310. During the adjustment using the lightness slide bar 320, the adjustment is reflected on the image 350 in real time.

  The saturation slide bar 321 is used to adjust the saturation (c value) of the image 350. The maximum value / minimum value that can be specified with the saturation slide bar 321 is calculated from the reference color set with the dropper tool 330 and the value set with the color difference slide bar 310. During the adjustment by the saturation slide bar 321, the adjustment is reflected on the image 350 in real time.

  The hue slide bar 322 is used to adjust the hue (h value) of the image 350. The maximum value / minimum value that can be specified with the hue slide bar 322 is calculated from the reference color set with the dropper tool 330 and the value set with the color difference slide bar 310. During the adjustment by the hue slide bar 322, the adjustment is reflected on the image 350 in real time.

  The color difference slide bar 310 is used to adjust the sensitivity (that is, the specifiable range) of the lightness, saturation, and hue slide bars 320, 321, and 322.

  When the color difference slide bar 310 is set to “∞” (infinite), the sensitivity of the lightness, saturation, and hue slide bars 320, 321, and 322 is not adjusted. When the color difference slide bar 310 is set to “24”, the maximum / minimum values of the lightness, saturation, and hue slide bars G20, G21, and G22 are close to 24, respectively, with respect to the reference color specified by the eyedropper tool 330. To be automatically set. Similarly, when the color difference slide bar 310 is set to `` 12 '' or `` 6.5 '', the maximum / minimum values of the lightness, saturation, and hue slide bars G20, G21, and G22 are different from the reference color. Automatically set to 12 and 6.5. That is, the smaller the value of the color difference slide bar 310, the lower the sensitivity of the lightness, saturation, and hue slide bars G20, G21, and G22. Therefore, it is understood that it is better to set the value of the color difference slide bar 310 smaller when the user wants to make fine adjustments to the image.

  When the OK button 340 is pressed, the correction by the screen is applied to the image 350. When the cancel button 341 is pressed, all corrections on the screen are discarded and the image 350 returns to the state before the change.

Sensitivity automatic setting process Figure 4 shows the automatic setting process of various sensitivities (maximum value / minimum value that can be specified for each of brightness, saturation, and hue) according to the setting value of the color difference slide bar 310 in the GUI shown in FIG. It is a flowchart. This process is executed by the CPU of the client PC 100.

  First, the CPU determines whether or not the user has operated the color difference slide bar 310 (S110). If there is no operation, the process waits until an operation is performed, but if any operation is performed, the following processing is performed.

  First, the RGB value of the reference color selected by the dropper tool 330 is acquired (S111), and it is converted into LCh color coordinates (S112). Then, sensitivity calculation is performed for each of the lightness value L, saturation value C, and hue value h of LCh (S113, S115, S117), and the calculated sensitivity (maximum value / minimum of specifiable range). Value) is set as the maximum value / minimum value of each slide bar (S114, S116, S118).

  Hereinafter, the sensitivity calculation process in steps S113, S115, and S117 described above will be described in detail. FIG. 5 is a flowchart showing sensitivity calculation processing for each of lightness, saturation, and hue. That is, in the present embodiment, the same processing is performed in any of the lightness sensitivity calculation processing in step S113, the saturation sensitivity calculation processing in step S115, and the hue sensitivity calculation processing in step S117. It is.

  First, a constant α is added to the “input value (L / c / h)” obtained by the Lch conversion in step S112, and this is set to a “temporary value” (S210). Note that the constant α is a positive value when calculating the maximum value of each slide bar 320, 321, 322, and the constant α is a negative value when calculating the minimum value.

  Here, if the value of the constant α is increased, the sensitivity calculation process is accelerated, but the calculated maximum value / minimum value is highly likely to deviate greatly from the value set by the user with the color difference slide bar 310. . On the other hand, if the value of the constant α is reduced, the sensitivity calculation process takes time, but the calculated maximum value / minimum value can be brought close to the value set by the user with the color difference slide bar 310. Normally, by specifying α = ± 1 (α = 1 for the maximum value and α = −1 for the minimum value), both the calculation time and accuracy are appropriate.

  Next, the color difference ΔE between the “input value” and the “provisional value” is calculated based on the CIE1994 color difference formula shown below (S211). Here, the CIE1994 color difference formula is known as an index for expressing the difference between colors, and human sense is taken into consideration. Note that when calculating ΔE by the following equation, it is only necessary to perform computations for only the relevant portions of each parameter of L / c / h.

ΔE = [(Δh / Sh) ² + (ΔL / SL) ² + (Δc / Sc) ² +] ^1/2
Where SL = 1, Sc = 1 + 0.045c, Sh = 1 + 0.015c
Then, the calculation result (hereinafter, calculated color difference ΔE) is compared with the threshold value set by the color difference slide bar 310 (value Eth indicated by the color difference slide bar 310 operated in step S110) (S212), ΔE Is smaller than Eth, a constant α is further added to the “provisional value” (S213), and the process returns to step S211 to recalculate the CIE1994 color difference formula for the “provisional value” and “input value”. The obtained ΔE is re-compared with Eth (S212). On the other hand, if ΔE is larger than Eth in step S212, “provisional value” is set as “output value” (S214).

  By executing the sensitivity calculation process shown in FIG. 5 for each of the maximum value (α is positive) and the minimum value (α is negative), the sensitivity of the slide bar to each color parameter (L / c / h) (ie, Specifiable range) is set. By executing this sensitivity calculation process for each reference color designated by the dropper tool 330, it is possible to provide a slide bar that can be easily operated as a color tone parameter for any color.

  As described above, according to the present embodiment, the color difference slide bar 310 is provided as a color correction GUI, and the sensitivity of the slide bar can be adjusted for the color parameters of the Lch based on the set value and the CIE1994 color difference formula. . In other words, the maximum value / minimum value for each parameter of L / c / h is set so that the same CIE1994 color difference is obtained with respect to the reference color, so that even if the user is between different parameters, the same level If the amount is corrected, the same color change can be seen.

  In this way, in this embodiment, for any color, the amount of change in color with respect to the amount of change in each slide bar of lightness, saturation, and hue can be made almost equal, and the user has no sense of incongruity and is intuitive Color correction operation can be performed.

Modification Examples The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and can of course be implemented in various modes without departing from the scope of the invention. It is.

  For example, the functions realized by software in the above-described embodiments may be realized by hardware.

  In the above-described embodiment, the GUI for correcting the tone of image data has been described as an example. However, in other application software such as a paint application or a document creation application, the user selects a color, for example, as shown in FIG. It is also effective to apply the present invention as a color palette GUI for this purpose.

  In the above-described embodiment, the CIE1994 color difference formula is used when automatically setting the sensitivity of the slide bar. However, if the human sense is sufficiently taken into consideration, for example, it has recently been attracting attention as a uniform color space. It is also possible to use other color difference formulas such as CIECAM02.

  In the above-described embodiment, an example in which a slide bar is used as a GUI for color tone correction is shown. However, the same operation as this slide bar, that is, a control (for example, an up / down button or the like) that can quantitatively specify a correction amount. Of course, may be used.

[Other embodiments]
Although the embodiments have been described in detail above, the present invention can take embodiments as, for example, a system, an apparatus, a method, a program, or a storage medium (recording medium). The present invention may be applied to a system composed of a single device or an apparatus composed of a single device.

  In the present invention, a software program (in the embodiment, a program corresponding to the flowchart shown in the figure) that realizes the functions of the above-described embodiment is directly or remotely supplied to the system or apparatus, and the computer of the system or apparatus Is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, or the like.

  As a recording medium for supplying the program, for example, floppy (registered trademark) disk, hard disk, optical disk, magneto-optical disk, MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card , ROM, DVD (DVD-ROM, DVD-R).

  As another program supply method, a client computer browser is used to connect to an Internet homepage, and the computer program of the present invention itself or a compressed file including an automatic installation function is downloaded from the homepage to a recording medium such as a hard disk. Can also be supplied. It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  In addition, the program of the present invention is encrypted, stored in a storage medium such as a CD-ROM, distributed to users, and key information for decryption is downloaded from a homepage via the Internet to users who have cleared predetermined conditions. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  In addition to the functions of the above-described embodiments being realized by the computer executing the read program, the OS running on the computer based on the instructions of the program is a part of the actual processing. Alternatively, the functions of the above-described embodiment can be realized by performing all of them and performing the processing.

  Furthermore, after the program read from the recording medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion board or The CPU or the like provided in the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also realized by the processing.

1 is a diagram illustrating a configuration of an image processing system according to an embodiment of the present invention. It is a block diagram which shows the structure of the image processing function in this embodiment. It is a figure which shows an example of GUI in this embodiment. It is a flowchart which shows the sensitivity automatic setting process in this embodiment. It is a flowchart which shows the detail of the sensitivity calculation process in this embodiment. It is a figure which shows the color palette GUI example as other embodiment.

Claims (13)

A reference color specifying means for specifying a reference color to be corrected in the image data;
Parameter specifying means for specifying a hue parameter value of the reference color;
Color correcting means for correcting the reference color to be the specified tone parameter value;
Image display means for displaying the image data using the corrected reference color;
An image processing apparatus comprising:
Color difference designating means for designating a color difference with respect to the reference color;
Correction range setting means for setting a specifiable range of color tone parameter values in the parameter specifying means based on the color difference;
An image processing apparatus comprising:   The image processing apparatus according to claim 1, wherein the correction range setting unit sets a specifiable range of the tone parameter value based on a CIE1994 color difference formula.   The correction range setting means is such that the color difference based on the CIE1994 color difference formula between the maximum and minimum values of the color tone parameter value that can be specified and the reference color approaches the color difference specified by the color difference specifying means. The image processing apparatus according to claim 2, wherein the maximum value and the minimum value are set.   The image processing apparatus according to claim 1, wherein the tone parameter includes at least one of brightness, saturation, and hue.   5. The image processing apparatus according to claim 1, wherein the parameter designating unit quantitatively instructs a correction amount of the color tone parameter.   6. The image processing apparatus according to claim 5, wherein the parameter designating unit instructs a correction amount of the color tone parameter value by a slide bar.   The image processing apparatus according to claim 1, wherein the reference color designating unit designates the reference color on an image displayed on the image display unit. A reference color specifying step for specifying a reference color to be corrected in the image data;
A color difference specifying step of specifying a color difference with respect to the reference color;
A correction range setting step for setting a specifiable range of a tone parameter value for the reference color based on the color difference;
A parameter designating step of designating a hue parameter value of the reference color within the specifiable range;
A color correction step for correcting the reference color to be the specified tone parameter value;
An image display step of displaying the image data using the corrected reference color;
An image processing method comprising:   9. The image processing method according to claim 8, wherein in the correction range setting step, a specifiable range of the tone parameter value is set based on a CIE1994 color difference formula.   In the correction range setting step, the color difference based on the CIE1994 color difference formula between the maximum value and the minimum value of the tone parameter value that can be specified and the reference color approaches the color difference specified in the color difference specification step. The image processing method according to claim 9, wherein the maximum value and the minimum value are set.   The image processing method according to claim 8, wherein the tone parameter includes at least one of brightness, saturation, and hue.   A program that causes an information processing apparatus to operate as the image processing apparatus according to claim 1 by controlling the information processing apparatus.   A recording medium on which the program according to claim 12 is recorded.

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