JP2007102118A - Image processing device, control method therefor, program, and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve work efficiency of a user when adjusting brightness of an image on a display. <P>SOLUTION: An image processing device includes: a display part for displaying an image data 21; a first display control part for displaying an adjustment quantity input slider 22 for inputting the gain adjustment quantity of the image data to the display part; a maximum unsaturated gain calculation part for calculating a maximum unsaturated gain as a maximum gain adjustment quantity in which each pixel data of the image data is not saturated; and a second display control part for displaying a warning range as a range exceeding the maximum unsaturated gain of the adjustment quantity input slider to the display part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for interactively setting image processing parameters on a screen.

  Conventionally, image data captured by a digital camera or the like is generally processed on a personal computer, and the processed image is displayed on a display or printed by a printer.

In particular, when image data shot with a digital camera or the like is underexposed and entirely dark (low brightness) image data, a process of increasing the image data by gain may be performed. In that case, conventionally, interactive gain adjustment is performed in which an image is first displayed on the display, the brightness is adjusted by the user interactively specifying the gain increase amount, and the adjusted image is displayed again on the display. I have been.
Japanese Patent Application Laid-Open No. 11-075076

  However, when adjusting the gain of the image, the pixel data may be saturated if the gain increase adjustment amount is too large. For example, in JPEG image data, the gradation of an image is often expressed in 8 bits. In this case, the gradation of brightness that can be expressed is 256 levels (0 to 255), and when the brightness of the original pixel data is 200, for example, if a gain of 1.5 times is applied, the pixel The brightness of the data is 300, and saturation exceeds the number of gradations 255 that can be expressed.

  In this case, Japanese Patent Laid-Open No. 11-075076 (Patent Document 1) discloses that a saturated pixel in the image is replaced with a warning color such as red and displayed on the display to notify and warn the user of the saturation. Has been. In this way, the user can perform an appropriate gain adjustment by repeating the work of reducing the gain increase amount by looking at the warning color display.

  However, this method has a problem in that work efficiency is poor because the user does not know whether the saturation occurs unless the gain is actually adjusted.

  Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to improve user work efficiency when adjusting the brightness of an image on a display.

  In order to solve the above-described problems and achieve the object, an image processing apparatus according to the present invention includes display means for displaying image data, and adjustment for inputting a gain adjustment amount of the image data to the display means. First display control means for displaying a quantity input means, maximum unsaturated gain calculating means for calculating a maximum unsaturated gain that is a maximum gain adjustment amount at which each pixel data of the image data is not saturated, and the display The means further comprises second display control means for displaying a warning range which is a range exceeding the maximum desaturation gain of the adjustment amount input means.

  A control method for an image processing apparatus according to the present invention is a method for controlling an image processing apparatus including display means for displaying image data, in order to input a gain adjustment amount of the image data to the display means. A first display control step for displaying the adjustment amount input means, a maximum desaturation gain calculation step for calculating a maximum desaturation gain which is a maximum gain adjustment amount at which each pixel data of the image data is not saturated, The display means comprises a second display control step of displaying a warning range that is a range exceeding the maximum desaturation gain of the adjustment amount input means.

  A program according to the present invention causes a computer to execute the above control method.

  A storage medium according to the present invention stores the above program.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to improve a user's working efficiency at the time of adjusting the brightness of an image on a display.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a block diagram showing the configuration of the first embodiment of the image processing apparatus of the present invention.

  In FIG. 1, reference numeral 101 denotes a CPU which controls the entire image processing apparatus. A keyboard 102 is used to input necessary information to the image processing apparatus together with the mouse 102a. Reference numeral 103 denotes a display unit, which includes a CRT, a liquid crystal display device, and the like. A ROM 104 and a RAM 105 constitute a storage device of the image processing apparatus, and store programs executed by the image processing apparatus and data used by the image processing apparatus. A hard disk device (HDD) 106 and a flexible disk device (FDD) 107 constitute an external storage device used for the file system of the image processing apparatus. Reference numeral 108 denotes a printer.

  Note that the image processing apparatus of the present embodiment may be in a format realized by starting application software on a general personal computer, or may be in a format configured as a dedicated image processing apparatus.

  FIG. 2 is a diagram illustrating a configuration example of a screen displayed on the display unit 103 by executing the application software in the present embodiment.

  In FIG. 2, 21 is an image display area, and 22 is a gain adjustment slider.

  Image data stored in the HDD 106 is decoded and displayed in the image display area 21. The slider 22 can specify an adjustment amount in a range of ± 10 centering on 0. When the user specifies the adjustment amount, the gain of the image data is adjusted according to an algorithm described later, and the adjusted image is displayed in the image display area 21. The In addition, in the figure, the portion where the gain is +6 or more is displayed with a warning in red, but this is calculated and displayed on the image data according to the algorithm described later, and is automatically displayed according to the image. Will change. When the user adjusts the gain, the user can know the limit of saturation before actually adjusting the gain by looking at the warning display displayed on the slider, thereby improving the work efficiency. Note that even if there is a saturated pixel, the image does not necessarily fail. For example, even if a warning is displayed for a portion of +6 or more, an adjustment amount in the range of +6 to +10 can be indicated on the slider.

[Explanation of gain adjustment processing]
FIG. 3 is a flowchart showing the flow of gain adjustment processing.

  The gain adjustment process will be described in detail using the flowchart shown in FIG.

  Note that the image data to be processed is an RGB image having a width of W pixels and a height of H pixels, and R (red), G (green), and G of the pixel at the position (i, j) starting from the upper left of the screen. The B (blue) component is treated as R (i, j), G (i, j), and B (i, j), respectively. Note that i is the horizontal coordinate of the pixel starting from the upper left of the screen, and j is the vertical coordinate of the pixel starting from the upper left of the screen. Further, the processed pixel data is expressed as R ′ (i, j), G ′ (i, j), B ′ (i, j). The adjustment amount designated by the user with the slider 22 is S (−10 ≦ S ≦ 10).

  In step S301, the variable F is initialized to zero. The variable T is initialized according to the following equation.

T ← 1.0 + S / 20.0
Here, the variable F is a value indicating whether or not a pixel in the screen is saturated, and takes a value 1 when it is saturated and a value 0 when it is not saturated. The variable T is a value indicating a gain to be applied to the pixel data.

  According to the above equation, the variable T takes a value between 0.5 and 1.5 according to the instruction by the user's slider.

  In step S302, the variable j is initialized to 0.

  In step S303, the variable i is initialized to 0.

  In step S304, the variable V is calculated according to the following equation.

V ← R (i, j) * T
Here, the variable V is a value indicating the brightness of the pixel when the gain T is actually multiplied.

  In step S305, V is compared with the maximum number of gradations Vmax that can be expressed. Vmax is 255 when the image data is 8-bit data, and 65535 when the image data is 16-bit data. If V ≦ Vmax, that is, if the brightness V of the pixel after multiplying by the gain T does not exceed the maximum number of gradations Vmax that can be expressed, the process proceeds to step S306; otherwise, the process proceeds to step S307.

  In step S306, since the brightness V of the pixel multiplied by the gain in step S304 does not exceed the maximum number of gradations Vmax that can be expressed, V is substituted into R '(i, j).

  In step S307, the brightness V of the pixel multiplied by the gain in step S304 exceeds the maximum number of gradations Vmax that can be expressed (saturated), so the maximum value that can be expressed in R ′ (i, j). The number of gradations Vmax is substituted. At the same time, a value 1 indicating that the brightness of the pixel after gain adjustment exceeds the maximum number of gradations that can be expressed (saturated) is substituted for the variable F, and the process proceeds to step S308.

  Next, the processing from step S304 to step S307 is similarly performed for G and B.

  That is, in step S308, the variable V is calculated according to the following equation.

V ← G (i, j) * T
In step S309, V is compared with a constant Vmax. If V ≦ Vmax, the process proceeds to step S310; otherwise, the process proceeds to step S311.

  In step S310, V is substituted into G '(i, j).

  In step S311, Vmax is substituted for G '(i, j), value 1 is substituted for variable F, and the process proceeds to S312.

  In step S312, the variable V is calculated according to the following equation.

V ← B (i, j) * T
In step S313, V is compared with a constant Vmax. If V ≦ Vmax, the process proceeds to step S314; otherwise, the process proceeds to step S315.

  In step S314, V is substituted into B '(i, j).

  In step S315, Vmax is substituted for B '(i, j), value 1 is substituted for variable F, and the flow proceeds to S316.

  In step S316, the variable i is incremented by “1”.

  In step S317, i and W are compared, and if they are equal, the process proceeds to S318. Otherwise, the process returns to S304.

  In step S318, the variable j is incremented by “1”.

  In step S319, j and H are compared. If they are equal, the process is completed assuming that the gain adjustment for all the pixels has been completed. Otherwise, the process returns to S303.

  With the above processing, the gain adjustment of the image data can be performed based on the setting of the slider by the user. Further, since the value of the variable F is 1 when a saturated pixel exists, and 0 when it does not exist, it can be determined whether saturation has occurred during the gain correction process.

[Explanation of maximum desaturation gain calculation process]
The maximum unsaturated gain calculation process will be described in detail using the flowchart shown in FIG.

  Note that the flowchart shown in FIG. 3 shows an operation of actually adjusting the gain of the image data interactively on the screen, whereas FIG. 4 shows the warning display shown in FIG. It shows the operation for calculating which position on the screen to display. Therefore, the operation shown in FIG. 4 is performed in order to determine the range for displaying the warning prior to the operation for actually adjusting the gain of the image data on the screen as shown in FIG. The adjusted image is not displayed on the display unit 103.

  In step S401, the variable k is initialized to a value of 1. This variable k corresponds to the designated position S on the slider 22 designated by the user in the flowchart of FIG.

  In step S402, assuming that k is set to the value of S in the flowchart of FIG. 3, gain adjustment processing is performed according to the flowchart of FIG.

  In step S403, it is determined whether there is a saturated pixel. With reference to the variable F already described, if F is 1, it is determined that there is a saturated pixel. When there is a saturated pixel, the process proceeds to step S404.

  In step S404, a warning is displayed based on the value of k. For example, if k = 6, it means that saturated pixels are generated when the slider is set to +6 or more. Therefore, as shown in FIG. 2, the range of +6 to +10 of the slider is displayed in red as a warning, and the process is terminated. To do.

  In step S405, the variable k is incremented by “1”.

  In step S406, the variable k is compared with the value 10. If k> 10, the process ends. Otherwise, the process returns to step S402.

  With the above processing, the warning display position can be calculated when warning display indicating that saturation occurs on the gain adjustment slider 22. The user can improve the work efficiency by performing the gain adjustment work as shown in FIG. 3 while looking at the warning display.

(Second Embodiment)
The configuration of the image processing apparatus in the second embodiment is the same as that of the first embodiment shown in FIG.

  The second embodiment is different from the first embodiment in the way of displaying a warning on the gain adjustment slider.

  FIG. 5 is a diagram illustrating a configuration example of a screen displayed on the display unit 103 by executing the application software in the present embodiment.

  In FIG. 5, 51 is an image display area, and 52 is a gain adjustment slider. Reference numeral 53 denotes a saturation allowance setting slider.

  Image data stored in the HDD 106 is decoded and displayed in the area 51. The slider 52 can designate an adjustment amount in a range of ± 10 centering on 0. When the user designates the adjustment amount, the gain of the image data is adjusted according to an algorithm described later, and the adjusted image is displayed in the area 51. Also, in the figure, the gain range of +6 to +7 is displayed in yellow, and the portion above +7 is displayed in red. This is because the maximum unsaturated gain adjustment amount is calculated for the image data according to the algorithm described later. It is displayed and changes automatically depending on the image.

  In the first embodiment, if even one pixel is saturated, a warning is displayed. However, in gain adjustment, there is a case where it is desired to adjust a part of a highlight part intentionally to a clear image. In the second embodiment, as a configuration in such a case, even if a predetermined percentage of pixels of the entire image is saturated, a warning (red) is not displayed, but a semi-warning display (yellow) is performed. . The ratio is specified using the slider 53. In FIG. 5, it is 0.5%, that is, a range in which no pixel is saturated in the image is not warned, and a range in which the number of pixels less than 0.5% of the number of pixels in the image is saturated is displayed in yellow. The range where 0.5% or more pixels are saturated is displayed in red. The ratio of red to yellow changes according to the operation of the slider 53. When 0% is specified by the slider 53, the warning display is all red as in the first embodiment, and the yellow warning portion becomes larger as the specified value of the slider 53 is larger. To increase.

  When the user adjusts the gain, the user can know the limit amount that saturates before actually adjusting the gain by looking at the warning displayed on the slider, thereby improving the working efficiency. Note that even if there is a saturated pixel, the image does not necessarily fail. For example, even if a portion above +6 is displayed as a semi-warning or warning, an adjustment amount in the range of +6 to +10 is indicated on the slider. You can also.

[Explanation of gain adjustment processing]
FIG. 6 is a flowchart showing the flow of gain adjustment processing.

  The gain adjustment process will be described in detail using the flowchart shown in FIG.

  The image data to be processed is a YUV image having a width W pixel and a vertical H pixel size, and Y (U, V) components of the pixel at the position (i, j) starting from the upper left of the screen are Y ( i, j), U (i, j), and V (i, j). Note that i is the horizontal coordinate of the pixel starting from the upper left of the screen, and j is the vertical coordinate of the pixel starting from the upper left of the screen. Further, the processed image is expressed as Y ′ (i, j), U ′ (i, j), V ′ (i, j).

  In the present embodiment, a YUV image is targeted. However, since an image can be converted from a YUV space to an RGB space by a known method, it goes without saying that an equivalent process can be performed on an RGB image.

  Further, an adjustment amount designated by the user with the slider 52 is S (−10 ≦ S ≦ 10).

  In step S601, a variable F is initialized to zero. The variable T is initialized according to the following equation.

T ← 1.0 + S / 20.0
Here, the variable F is a value indicating the number of saturated pixels in the screen, and the variable T is a value indicating the gain to be applied to the pixel data.

  According to the above expression, the variable T takes a value between 0.5 and 1.5 according to the instruction by the user's slider.

  In step S602, the variable j is initialized to the value 0.

  In step S603, the variable i is initialized to 0.

  The steps so far are the same as steps S301 to S303 in FIG. 3 showing the first embodiment.

  In step S604, the variable V is calculated according to the following equation.

V ← Y (i, j) * T
In step S605, V is compared with the maximum number of gradations Vmax that can be expressed. Vmax is 255 when the image data is 8-bit data, and 65535 when the image data is 16-bit data. If V ≦ Vmax, that is, the brightness V of the pixel after multiplying the gain T does not exceed the maximum number of gradations Vmax that can be expressed, the process proceeds to step S606, and if not, the process proceeds to step S607.

  In step S606, since the brightness V of the pixel multiplied by the gain in step S604 does not exceed the maximum number of gradations Vmax that can be expressed, V is substituted into Y '(i, j).

  In step S607, since the brightness V of the pixel multiplied by the gain in step S604 exceeds the maximum number of gradations Vmax that can be expressed (saturated), the maximum value that can be expressed in Y ′ (i, j). The number of gradations Vmax is substituted. At the same time, the variable F is incremented by 1 and the process proceeds to step S608.

  In step S608, U (i, j) is substituted for U '(i, j), and V (i, j) is substituted for V' (i, j). This is because the saturation does not change during gain adjustment, and only the luminance component needs to be changed.

  In step S609, the variable i is incremented by “1”.

  In step S610, i and W are compared, and if they are equal, the process proceeds to step S611. Otherwise, the process returns to step S604.

  In step S611, the variable j is incremented by “1”.

  In step S612, j and H are compared. If they are equal, the process is completed assuming that the gain adjustment for all the pixels has been completed. Otherwise, the process returns to S603.

  With the above processing, the gain adjustment of the image data can be performed based on the setting of the slider 52 by the user. In addition, since the number of saturated pixels is stored in the variable F, processing corresponding to the number of saturated pixels can be performed in the subsequent processing.

[Explanation of maximum desaturation gain and allowable saturation gain calculation processing]
The maximum non-saturation gain and allowable saturation gain calculation processing will be described in detail using the flowchart shown in FIG.

  Note that the flowchart shown in FIG. 6 shows an operation of actually adjusting the gain of the image data interactively on the screen, whereas FIG. 7 shows the warning display shown in FIG. It shows the operation for calculating which position on the screen to display. For this reason, the operation shown in FIG. 7 is performed to determine the range for displaying the warning prior to the operation for actually adjusting the gain of the image data on the screen as shown in FIG. The adjusted image is not displayed on the display unit 103.

  Let the saturation tolerance specified by the slider 53 by the user be Q (0.0 ≦ Q ≦ 1.0).

  In step S701, the variable k is initialized to the value 1, and the variables p and q are initialized to the value 0. Note that the variable p indicates the maximum non-saturation gain (displayed in yellow when exceeding this), and the variable q indicates the allowable saturation gain (displayed in red when exceeding this).

  In step S702, assuming that k is set to the value of S in the flowchart of FIG. 6, gain adjustment processing is performed according to the flowchart of FIG.

  In step S703, the number of saturated pixels F is compared with the value 0. If F> 0, the process proceeds to step S704, and if not, the process proceeds to S708.

  In step S704, the variable p is compared with the value 0. If p = 0, the process proceeds to step S705, and if not, the process proceeds to step S706.

  In step S705, k is substituted for p.

  In step S706, F is compared with W * H * Q / 100. If F> W * H * Q / 100, the process proceeds to step S707; otherwise, the process proceeds to step S708.

  In step S707, k is substituted for q, and the process proceeds to step S710.

  In step S708, the variable k is incremented by “1”.

  In step S709, the variable k is compared with the value 10. If k> 10, the process proceeds to step S710. Otherwise, the process returns to step S702.

  In step S710, a warning is displayed on the gain adjustment slider 52 based on the variables p and q. The variable p stores the maximum non-saturation gain (displayed in yellow when exceeding this), and the allowable saturation gain (displayed in red when exceeding this) is stored in the variable q. In addition, when there is no corresponding gain value, values 0 are stored in p and q, respectively.

  With the above processing, a warning display indicating that saturation occurs can be performed on the gain adjustment slider 52. The user can improve the work efficiency by performing the gain adjustment work while watching the warning display.

(Other embodiments)
In the above embodiment, the gain adjustment slider has 21 steps from -10 to +10. However, the present invention is not limited to this, and it goes without saying that an arbitrary number of steps may be provided. The relationship between the slider scale S and the adjustment parameter (gain) T is not shown in step S301, but may be based on an arbitrary expression.

  In the first embodiment, gain adjustment is performed in the RGB color space, and it is determined that the pixel is saturated when any value of R, G, or B exceeds the value range. However, the present invention is not limited to this. For example, the case where all three RGB values exceed the range may be saturated.

  Further, in the above embodiment, the saturation is determined based on whether the value range (up to 255 in the case of 8 bits) is exceeded. However, even if a predetermined saturation threshold value (for example, 250) is exceeded, it is defined as saturation. Alternatively, the user may be allowed to specify the saturation threshold interactively.

  In the above embodiment, an example in which gain adjustment is performed for an RGB image or a YUV image has been described. However, the present invention is not limited to this, and the same processing can be performed for an image in another color space such as Lab or XYZ. Needless to say. Further, for example, in the case of an RGB image, gain adjustment may be performed directly on the RGB space, or gain conversion may be performed on the YUV space after being converted into a YUV image by a known method.

  The object of each embodiment is also achieved by the following method. That is, a storage medium (or recording medium) in which a program code of software that realizes the functions of the above-described embodiments is recorded is supplied to the system or apparatus. Then, the computer (or CPU or MPU) of the system or apparatus reads and executes the program code stored in the storage medium. In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention. Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but the present invention includes the following cases. That is, based on the instruction of the program code, an operating system (OS) running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  Furthermore, the following cases are also included in the present invention. That is, the program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion card or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

  When the present invention is applied to the above storage medium, the storage medium stores program codes corresponding to the procedure described above.

1 is a block diagram showing a configuration of a first embodiment of an image processing apparatus of the present invention. It is a figure which shows the structural example of the screen displayed on a display part by execution of the application software in 1st Embodiment. It is a flowchart explaining the flow of the gain adjustment process of 1st Embodiment. It is a flowchart explaining the flow of the maximum desaturation gain calculation processing of 1st Embodiment. It is a figure which shows the structural example of the screen displayed on a display part by execution of the application software in 2nd Embodiment. It is a flowchart explaining the flow of the gain adjustment process of 2nd Embodiment. It is a flowchart explaining the flow of the maximum desaturation gain and allowable saturation gain calculation processing of 2nd Embodiment.

Explanation of symbols

101 CPU
102 Keyboard 103 Display 104 ROM
105 RAM
106 Hard Disk 107 Flexible Disk Device 108 Printer

Claims (12)

Display means for displaying image data;
First display control means for displaying an adjustment amount input means for inputting a gain adjustment amount of the image data on the display means;
A maximum desaturation gain calculating means for calculating a maximum desaturation gain that is a maximum gain adjustment amount at which each pixel data of the image data is not saturated;
Second display control means for displaying on the display means a warning range that is a range exceeding the maximum desaturation gain of the adjustment amount input means;
An image processing apparatus comprising:   The image processing apparatus according to claim 1, wherein the second display control unit displays the warning range so as to overlap the adjustment amount input unit.   The image processing apparatus according to claim 1, further comprising: an allowable saturation gain calculating unit that calculates an allowable saturation gain that is a gain adjustment amount that saturates an allowable amount of pixel data in the image data. .   The image processing apparatus according to claim 3, further comprising a third display control unit that displays an allowable amount input unit for inputting the allowable amount on the display unit.   The second display control means displays, as the warning range, a first range between the maximum non-saturation gain and the allowable saturation gain, and a second range exceeding the allowable saturation gain, The image processing apparatus according to claim 3, wherein display states of the first range and the second range are made different. A method for controlling an image processing apparatus comprising display means for displaying image data,
A first display control step of displaying an adjustment amount input means for inputting a gain adjustment amount of the image data on the display means;
A maximum unsaturated gain calculating step for calculating a maximum unsaturated gain that is a maximum gain adjustment amount at which each pixel data of the image data is not saturated;
A second display control step of displaying a warning range that is a range exceeding the maximum desaturation gain of the adjustment amount input means on the display means;
A control method for an image processing apparatus.   The method according to claim 6, wherein, in the second display control step, the warning range is displayed so as to overlap the adjustment amount input unit.   The image processing apparatus according to claim 6, further comprising an allowable saturation gain calculating step of calculating an allowable saturation gain, which is a gain adjustment amount that saturates an allowable amount of pixel data in the image data. Control method.   9. The control method for an image processing apparatus according to claim 8, further comprising a third display control step of displaying an allowable amount input means for inputting the allowable amount on the display means.   In the second display control step, as the warning range, a first range between the maximum non-saturation gain and the allowable saturation gain and a second range exceeding the allowable saturation gain are displayed. 9. The method according to claim 8, wherein display states of the first range and the second range are made different.   A program for causing a computer to execute the control method according to any one of claims 6 to 10.   A computer-readable storage medium storing the program according to claim 11.

Images