JP2005284493A - Image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image processing apparatus capable of improving operability. <P>SOLUTION: The color tone of pixel data forming image data is corrected by an image quality adjusting circuit 28 on the basis of a reference H component value, a reference C component value and a reference L component value which are set in a reference value table and a target H component value, a target C component value and a target L component value which are set in a target value table. The image based on the image data whose color tone is corrected is displayed on an LCD monitor 34 by a video encoder 30. A character generator 36 displays a cursor on the LCD monitor 34 as OSD. When a set key 56 is depressed, a CPU 46 detects the hue of a pixel to which the cursor is directed. In addition, the CPU 46 specifies reference value numbers allocated to two reference H component values having hues to be pinched by the detected hue and sets two target C component values allocated to the same target value numbers as the specified reference value numbers to "0". <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus that is applied to, for example, a digital camera and corrects the color tone of a display image.

An example of a conventional image processing apparatus of this type is disclosed in Patent Document 1. This prior art intends to correct the color tone of image data photographed by an image sensor using a plurality of reference values and a plurality of target values respectively corresponding to a plurality of representative colors. Here, when one of a plurality of representative colors is selected and the dial key is operated, the target value corresponding to the selected representative color is changed. As a result, color tone correction according to preference is realized.
JP 2003-9161 A [H04N 1/46, 1/60, 9/04, 9/68, G06T 1/00]

    However, the conventional technique has a problem in that it lacks operability because an operation of selecting any one of the target values of representative colors prepared in advance on the menu is necessary. Further, since only the target value of the representative color prepared in advance can be changed, it is not always possible to correct the color tone of the operator's favorite color.

    Therefore, a main object of the present invention is to provide an image processing apparatus capable of improving operability.

    Another object of the present invention is to provide an image processing apparatus capable of correcting the tone of a desired color.

  The image processing apparatus according to the first aspect of the present invention is corrected by correction means and correction means for correcting the color tone of each of a plurality of pixels forming an image based on a plurality of color tone correction coefficients respectively assigned to a plurality of representative colors. First display means for displaying the displayed image, second display means for displaying a pointer on the image displayed by the first display means, and detection means for detecting the hue of the pixel pointed by the pointer when the first operation is accepted Update means for specifying two representative colors having hues sandwiched between hues detected by the detection means, and two tone correction coefficients assigned to the two representative colors specified by the specifying means to a predetermined value Means.

  The color tone of each of the plurality of pixels forming the image is corrected by the correction unit based on a plurality of color tone correction coefficients respectively assigned to the plurality of representative colors. The corrected image is displayed by the first display means. The second display means displays a pointer on the image displayed by the first display means. When the first operation is accepted, the hue of the pixel pointed by the pointer is detected by the detecting means. The specifying unit specifies two representative colors having hues that sandwich the detected hue, and the updating unit updates two tone correction coefficients assigned to the two specified representative colors to a predetermined value. The color tone of the image displayed by the first display means is changed by updating the color tone correction coefficient.

  When the first operation is performed in a state where the pointer points to an arbitrary pixel, the tone correction coefficients assigned to the two representative colors related to the hue of the arbitrary pixel are updated. The color tone of the image displayed by the first display means is changed by updating the color tone correction coefficient. That is, the color tone of the display image is changed by a simple operation directed to the display image. Thereby, the operability can be improved.

  An image processing apparatus according to a second aspect of the invention is dependent on the first aspect, wherein the hue is defined by hue, saturation, and brightness, and the hue correction coefficient is a coefficient that corrects at least one of hue, saturation, and brightness. .

  An image processing apparatus according to a third aspect of the present invention is dependent on the first or second aspect, wherein the image displayed by the first display means is a still image, and the second display means arbitrarily designates a pointer when the second operation is accepted. Move in the direction of. In this case, desired color tone correction is realized by the second operation and the subsequent first operation.

  An image processing apparatus according to a fourth aspect of the invention is dependent on any one of the first to third aspects, wherein the correction means includes two tone correction coefficients respectively assigned to two representative colors having hues sandwiching the hue of the target pixel. Is used to correct the tone of the pixel of interest.

  An image processing apparatus according to a fifth aspect of the invention is dependent on any one of the first to fourth aspects, further comprising storage means for storing a plurality of reference coefficients respectively corresponding to a plurality of representative colors, and the correction amount of the correction means is According to the difference between the plurality of reference coefficients and the plurality of tone correction coefficients stored by the storage unit.

  The image processing apparatus according to the invention of claim 6 is corrected by correction means and correction means for correcting the color tone of each of a plurality of pixels forming an image based on a plurality of color tone correction coefficients respectively assigned to a plurality of representative colors. First display means for displaying an image, reception means for receiving a selection operation for selecting an arbitrary pixel on the image displayed by the first display means, and a new representative color based on the hue of the pixel selected by the selection operation And a allocating unit for assigning a new color correction coefficient to the representative color defined by the defining unit.

  The color tone of each of the plurality of pixels forming the image is corrected by the correction unit based on a plurality of color tone correction coefficients respectively assigned to the plurality of representative colors. The corrected image is displayed by the first display means. When the selection operation for selecting an arbitrary pixel on the displayed image is received by the reception unit, the definition unit defines a new representative color based on the hue of the pixel selected by the selection operation. The assigning means assigns a new color correction coefficient to the representative color defined by the defining means.

  That is, the new representative color is defined based on the hue of the pixel selected by the selection operation, and the new tone correction coefficient is assigned to the thus defined representative color. The color tone of the display image is corrected based on the new color tone correction coefficient. As a result, it is possible to perform tone correction for a desired color.

  An image processing apparatus according to a seventh aspect of the invention is dependent on the sixth aspect, further comprising second display means for displaying a pointer on the image displayed by the first display means, and any pixel is directed by the pointer. Pixel. This improves operability.

  An image processing apparatus according to an invention of claim 8 is dependent on claim 6 or 7, wherein each of the plurality of tone correction coefficients includes a hue correction coefficient and a saturation correction coefficient, and the assigning means assigns a new representative color with respect to the hue. A specifying means for specifying two representative colors to be sandwiched, and a hue correction coefficient for forming a new hue correction coefficient by performing linear interpolation on the two hue correction coefficients respectively assigned to the two representative colors specified by the specifying means First creation means for creating is included. As a result, the value of the new hue correction coefficient does not deviate significantly from the value of the surrounding color complementation coefficient.

  An image processing apparatus according to a ninth aspect of the invention is dependent on the eighth aspect, and the assigning means further includes second creating means for creating a new tone correction coefficient and creating a saturation correction coefficient indicating a predetermined value. The saturation of the selected pixel is corrected in a predetermined direction by a saturation correction coefficient indicating a predetermined value.

  The image processing apparatus according to the invention of claim 10 is dependent on claim 8 or 9, wherein the correction means includes two hue correction coefficients respectively assigned to two representative colors having hues sandwiching the hue of the target pixel, and two The color tone of the target pixel is corrected using the saturation correction coefficient.

  An image processing apparatus according to an invention of claim 11 is dependent on any one of claims 6 to 10, and further comprises storage means for storing a plurality of reference coefficients respectively corresponding to a plurality of representative colors, and the correction amount of the correction means is According to the difference between the plurality of reference coefficients and the plurality of tone correction coefficients stored by the storage unit.

  According to the first aspect of the present invention, when the first operation is performed with the pointer pointing to an arbitrary pixel, the tone correction coefficients assigned to the two representative colors related to the hue of the arbitrary pixel are updated. The The color tone of the image displayed by the first display means is changed by updating the color tone correction coefficient. That is, the color tone of the display image is changed by a simple operation directed to the display image. Thereby, the operability can be improved.

  According to the invention of claim 4, the new representative color is defined based on the hue of the pixel selected by the selection operation, and the new tone correction coefficient is assigned to the thus defined representative color. The color tone of the display image is corrected based on the new color tone correction coefficient. As a result, it is possible to perform tone correction for a desired color.

  The above object, other objects, features and advantages of the present invention will become more apparent from the following detailed description of embodiments with reference to the drawings.

  Referring to FIG. 1, a digital camera 10 of this embodiment includes a focus lens 12. The optical image of the subject enters the light receiving surface of the image sensor 14 through the focus lens 12. On the light receiving surface, a charge (raw image signal) corresponding to the incident optical image is generated by photoelectric conversion. The light receiving surface is covered with a primary color Bayer array color filter (not shown), and each pixel signal forming a camera signal is one of R (Red), G (Green), and B (Blue). Has only one color information.

  When the camera mode is selected by the mode key 60, a corresponding status signal is given from the system controller 48 to the CPU 46. The CPU 46 gives processing instructions to the TG (Timing Generator) 16, the signal processing circuit 22, and the video encoder 30 in order to execute the through image display processing.

  The image sensor 14 is driven by the TG 16, whereby the raw image signal is repeatedly read from the image sensor 14. The read raw image signal of each frame is converted into a digital signal by the A / D converter 20 through known noise removal and level adjustment in the CDS / AGC circuit 18.

  The signal processing circuit 22 performs signal processing such as color separation, white balance adjustment, and YUV conversion on the raw image data of each frame output from the A / D converter 20 to generate YUV format image data. The generated image data is written into the SDRAM 26 by the memory control circuit 24.

  The video encoder 30 reads the image data stored in the SDRAM 26 through the memory control circuit 24, and encodes the read image data of each frame into an NTSC format composite video signal. The encoded composite video signal is supplied to the LCD monitor 34 through the adder 32. A real-time moving image of the subject is displayed on the monitor screen.

  When the character signal is output from the character generator 36, the adder 32 adds the character signal to the composite video signal. Thereby, a desired character is displayed on the screen in an OSD manner.

  When the shutter button 50 is pressed by the operator, a corresponding status signal is given from the system controller 48 to the CPU 46, and the CPU 46 executes compression / recording processing. First, the CPU 46 issues a compression command to the JPEG codec 38. The JPEG codec 38 reads one frame of image data stored in the SDRAM 26 through the memory control circuit 24, performs JPEG compression on the read image data, and writes the compressed image data into the SDRAM 26 through the memory control circuit 24.

  Thereafter, the CPU 52 reads the compressed image data from the SDRAM 26 through the memory control circuit 24, and records the image file including the read compressed image data on the memory card 42 through the I / F circuit 40. The memory card 42 is a detachable non-volatile recording medium, and can be accessed by the CPU 46 when it is inserted into a slot (not shown).

  When the reproduction mode is selected by the mode key 60, a corresponding status signal is given from the system controller 48 to the CPU 46, and the reproduction process is executed by the CPU 46.

  The CPU 46 first reads the compressed image data stored in the image file in the memory card 42 through the I / F circuit 40 and writes the read compressed image data into the SDRAM 26 through the memory control circuit 24. The CPU 46 further provides a decompression command to the JPEG codec 38 and a processing command to the video encoder 30.

  The JPEG codec 38 reads the compressed image data stored in the SDRAM 26 through the memory control circuit 24, performs JPEG decompression on the read image data, and writes the decompressed image data into the SDRAM 26 through the memory control circuit 24.

  The video encoder 30 reads the image data stored in the SDRAM 26 through the memory control circuit 24, encodes the read image data into an NTSC format composite video signal, and monitors the encoded composite video signal through the adder 32. 34. As a result, the reproduced image is displayed on the monitor screen.

  When the image quality adjustment key 52 is operated in a state where a through image or a reproduced image is displayed on the LCD monitor 34, a corresponding status signal is given from the system controller 48 to the CPU 46, and the image quality adjustment processing is executed by the CPU 46. The

  If the current mode is the camera mode, the CPU 46 disables the TG 16 and the signal processing circuit 22. The display on the LCD monitor 34 changes from a through image to a freeze image. That is, when the image quality adjustment key 52 is operated, a still image such as a freeze image or a reproduced image is displayed on the monitor screen as shown in FIG. 13, for example.

  Next, the CPU 46 instructs the character generator 36 to output a character signal. The character signal output from the character generator 36 is given to the LCD monitor 34 via the adder 32. As a result, the cross-shaped cursor CS is OSD-displayed on the monitor screen as shown in FIG.

  When the cross key 54 is operated here, a corresponding status signal is given to the CPU 46. The CPU 46 issues a cursor movement command to the character generator 36. The character generator 36 changes the generation timing of the character signal, and as a result, the display position of the cursor CS moves in a desired direction.

  When the set key 56 is operated, a corresponding status signal is given to the CPU 46. The CPU 46 sets two target C component values sandwiching the hue of the pixel directed by the cursor CS to “0” among 12 target C component values set in a target value table 28j described later. When the change of the target value table 28j is completed, a processing command is issued to the image quality adjustment circuit 28.

  The image quality adjustment circuit 28 reads image data (corresponding to a freeze image or a reproduced image) stored in the SDRAM 26 through the memory control circuit 24, and performs color tone correction on the read image data. The image data whose color tone has been corrected is then written into the SDRAM 26 through the memory control circuit 24.

  The video encoder 30 reads the image data whose image quality has been adjusted in this way from the SDRAM 26. As a result, the image quality of the freeze image or playback still image displayed on the LCD monitor 34 changes. Specifically, the color directed by the cursor CS is deleted. For the flower image shown in FIG. 13, when the set key 56 is operated with the cursor CS pointing at the green leaf, the green color is erased from the screen.

  When the shutter button 50 is operated after the image quality is changed in this way, a corresponding status signal is given from the system controller 48 to the CPU 46, and the CPU 46 executes compression / recording processing. As a result, the image data whose image quality has changed is recorded in the memory card 42 in a compressed state.

  The image quality adjustment circuit 28 is configured as shown in FIG. The signal format of the image data read from the SDRAM 26 is converted from the YUV format to the LCH format by the LCH conversion circuit 28a. The L component (brightness component), C component (saturation component), and H component (hue component) forming the converted image data are supplied to the L adjustment circuit 28b, the C adjustment circuit 28c, and the H adjustment circuit 28d, respectively. The L adjustment circuit 28b, the C adjustment circuit 28c, and the H adjustment circuit 28d perform predetermined calculations on the input L component, C component, and H component, respectively, to obtain a corrected L component, a corrected C component, and a corrected H component. The obtained image data composed of the corrected H component, the corrected C component, and the corrected L component is then returned to the YUV format image data by the YUV conversion circuit 28e, and the YUV format image data is written into the SDRAM 26.

  The H component output from the LCH conversion circuit 28a is also provided to the region discrimination circuit 28f. The area discriminating circuit 28f refers to the reference value table 28i formed in the flash memory 28h, and discriminates the area to which the H component given from the LCH conversion circuit 28a belongs. The area determination circuit 28f also reads two reference values and two target values corresponding to the determination result from the reference value table 28i and the target value table 28j. Calculations by the L adjustment circuit 28b, the C adjustment circuit 28c, and the H adjustment circuit 28d are performed based on the read reference value and target value.

  Referring to FIG. 3, twelve reference H component values, twelve reference C component values, and twelve reference L component values are written in reference value table 28i. H, C, and L mean hue, saturation, and lightness, respectively, and are all parameters for color adjustment. The same reference value number N (0 to 11) is assigned to the reference H component value, the reference C component value, and the reference L component value that are related to each other, and three component values having the same reference value number (reference H component value, reference value) The reference value is defined by the C component value and the reference L component value. The twelve reference values are distributed in the YUV space as shown in FIGS. FIG. 6 shows only the reference value whose reference value number is “9”.

  On the other hand, the target value table 28j is formed as shown in FIG. Similar to the reference value table 28i shown in FIG. 3, twelve target H component values, twelve target C component values, and twelve target L values for each of hue (H), saturation (C), and lightness (L). The component value is set, and the target value is defined by the target H component value, the target C component value, and the target L component value assigned to the same target value number N (= 0 to 11). When the target H component value, the target C component value, and the target L component value indicate the numerical values shown in FIG. 4, the 12 target values are distributed in the YUV space as shown in FIGS. FIG. 6 shows only the target value whose target value number is “9”.

  As can be seen from FIG. 5, the reference value of N = 2 corresponds to “Magenta”, the reference value of N = 3 corresponds to “Red”, the reference value of N = 5 corresponds to “Yellow”, and N A reference value of = 8 corresponds to “Green”, a reference value of N = 10 corresponds to “Cyan”, and a reference value of N = 11 corresponds to “Blue”. The reference values of N = 0, 1, 4, 6, 7, and 9 correspond to colors other than the above-described colors. In this embodiment, the color defined by the reference value set in the reference value table 28i is defined as “representative color”.

  The area discriminating circuit 28f executes the process according to the flowchart shown in FIG. 7 for each pixel in order to perform the area discrimination and the selection of the reference value and the target value according to the discrimination result for each pixel forming the image data. First, the count value N of the counter 28n is set to “0” in step S1, and the reference H component value corresponding to the count value N is read from the reference value table 28i in step S3. In step S5, the H component value (current pixel H component value) of the current pixel input from the LCH conversion circuit 28a is compared with the reference H component value read from the reference value table 28i.

  If it is determined in step S5 that the reference H component value> the current pixel H component value, the count value N is compared with “0” in step S11. If N = 0, steps S13 to S19 are processed. If N> 1, steps S21 to S27 are processed. On the other hand, if the reference H component value ≦ the current pixel H component value, the counter 22s is incremented in step S7, and the updated count value N is compared with the maximum value Nmax in subsequent step S9. If N ≦ Nmax, the process returns to step S3. If N> Nmax, steps S21 to S27 are processed. The maximum value Nmax is the maximum value of the reference value number or the target value number, and is always “11” in this embodiment.

  In step S13, the reference H component value, the reference C component value, and the reference L component value corresponding to the current count value N are selected from the reference value table 28i as Hr1, Cr1, and Lr1, and in step S15, the current count value N The target H component value, target C component value, and target L component value corresponding to are selected from the target value table 28j as Ht1, Ct1, and Lt1. In step S17, the reference H component value, the reference C component value, and the reference L component value corresponding to the count value N-1 are selected from the reference value table 28i as Hr2, Cr2 and Lr2, and in step S19, the count value The target H component value, target C component value, and target L component value corresponding to N−1 are selected from the target value table 28j as Ht2, Ct2, and Lt2.

  On the other hand, in step S21, the reference H component value, the reference C component value, and the reference L component value corresponding to the count value N = 0 are selected from the reference value table 28i as Hr1, Cr1, and Lr1, and in step S23, the count value N The target H component value, target C component value, and target L component value corresponding to = 0 are selected from the target value table 28j as Ht1, Ct1, and Lt1. In step S25, the reference H component value, reference C component value, and reference L component value corresponding to the count value N = Nmax are selected from the reference value table 28i as Hr2, Cr2, and Lr2, and in step S27, the count value N = Target H component value, target C component value and target L component value corresponding to Nmax are selected from the target value table 28j as Ht2, Ct2 and Lt2.

  In this way, two reference values sandwiching the current pixel value with respect to the hue and two target values corresponding to the two reference values are detected.

  The reference H component values Hr1 and Hr2 and the target H component values Ht1 and Ht2 are given to the H adjustment circuit 28d. The reference C component values Cr1 and Cr2 and the target C component values Ct1 and Ct2 are given to the C adjustment circuit 28c. Further, the reference L component values Lr1 and Lr2 and the target L component values Lt1 and Lt2 are given to the L adjustment circuit 28b.

  The H adjustment circuit 28d takes in the current pixel H component value Hin from the LCH conversion circuit 28a, and calculates a corrected H component value Hout according to Equation 1. The calculated corrected H component value Hout is shifted to an angle indicated by a broken line in FIG.

  The H adjustment circuit 28d also outputs the angle data α (= | Hr2-Hin |) and β (= | Hr1-Hin |) to the C adjustment circuit 28c and the L adjustment circuit 28b, and the angle data γ (= | Ht2 -Hout |) and δ = (| Ht1-Hout |) are output to the L adjustment circuit 28b.

  The C adjustment circuit 28c performs the calculation shown in Equation 2 on the current pixel C component value Cin fetched from the LCH conversion circuit 28a to calculate the corrected C component value Cout shown in FIG.

  The C adjustment circuit 28c also calculates Equation 3 to calculate a straight line connecting the CH system coordinates (0, 0) and (Cin, Hin) and a straight line connecting the coordinates (Cr1, Hr1) and (Cr2, Hr2). The C component value Cr3 at the intersection coordinates and the C component at the intersection coordinates between the straight line connecting the coordinates (Ct1, Ht1) and (Ct2, Ht2) and the straight line connecting the coordinates (0, 0) and (Cout, Hout) of the CH system The value Ct3 is calculated. The calculated C component values Cr3 and Ct3 are output to the L adjustment circuit 28b together with the above-described current pixel C component value Cin and corrected C component value Cout.

  The L adjustment circuit 28b takes in the current pixel L component value Lin from the LCH conversion circuit 28a, and obtains a correction L component value Lout shown in FIG. Lmax and Lmin shown in FIG. 10 are the maximum and minimum values of L (brightness) that can be reproduced, respectively. The current pixel value (input pixel value) is a surface formed by coordinates (Lmax, 0, 0), (Lmin, 0, 0) and (Lr3, Cr3, Hin) of the LCH system (YUV space cut out by hue Hin) Existing on the surface). On the other hand, the correction pixel value is a surface formed by LCH coordinates (Lmax, 0, 0), (Lmin, 0, 0) and (Lt3, Ct3, Hout) (a surface obtained by cutting out the YUV space with the hue Hout). Exists on.

  A corrected pixel value is defined by the corrected H component value Hout, the corrected C component value Cout, and the corrected L component value Lout thus obtained. The current pixel value is defined by the current pixel H component value Hin, the current pixel C component value Cin, and the current pixel L component value Lin output from the LCH conversion circuit 28a.

  When the image quality adjustment key 52 is operated, the CPU 46 executes image quality adjustment processing according to the flowchart shown in FIG. The control program corresponding to this flowchart is stored in the flash memory 62.

  First, in step S31, it is determined whether or not the current mode is a camera mode. If “NO” here, the process directly proceeds to the step S35, but if “YES”, the TG 16 and the signal processing circuit 22 are disabled in a step S33, and then the process proceeds to the step S35.

  In step S35, the character generator 36 is instructed to output a character signal indicating the cursor CS. As a result, the cursor CS is displayed on the monitor screen.

  In step S37, it is determined whether or not the set key 56 has been operated. In step S43, it is determined whether or not the cross key 54 has been operated. In step S47, it is determined whether or not the shutter button 50 has been operated. In step S51, it is determined whether or not the cancel key 58 has been operated.

  When the set key 56 is operated, YES is determined in step S37, and table update processing is executed in step S39. In step S41, a processing command is issued to the image quality adjustment circuit 28. The image quality adjustment circuit 28 performs color tone correction with reference to the reference value table 28i and the target value table 28j updated in step S39. As a result, the color pointed to by the cursor CS is erased from the freeze image or the reproduced image displayed on the LCD monitor 34.

  When the cross key 54 is operated, YES is determined in step S43, and a command to move the cursor CS is issued to the character generator 36 in step S45. The character generator 36 changes the output timing of the character signal. As a result, the display position of the cursor CS moves in a desired direction.

  When the shutter button 50 is operated, YES is determined in the step S47, and the compression / recording process is executed in a step S49. As a result, the image data whose image quality has been adjusted is recorded in the memory card 42 in a compressed state. When the cancel key 58 is operated, YES is determined in the step S43, and the process returns to the upper hierarchy routine.

  The table update process in step S39 is executed according to a subroutine shown in FIG. First, in step S61, the hue of the pixel to which the cursor CS is directed is detected. Specifically, the pixel data of interest is read from the SDRAM 26 through the memory control circuit 24, LCH conversion is performed on the read pixel data, and the H component value is detected. In step S63, two reference H component values sandwiching the detected H component value are specified from the reference value table 28i, and in step S65, two reference value numbers respectively corresponding to the two specified reference H component values are detected. . In step S67, two target C component values respectively assigned to the same two target value numbers as the two detected reference value numbers are set to “0”. When the process of step S67 is completed, the process returns to the upper layer routine.

  As can be understood from the above description, the color tone of the pixel data forming the image data includes the reference values (reference H component value, reference C component value, and reference L component value) set in the reference value table 28i, and the target value table. Based on the target values (target H component value, target C component value, and target L component value) set to 28j, the image quality adjustment circuit 28 corrects the target value.

  Here, each of the plurality of reference values set in the reference value table 28i defines a representative color. The target value set in the target value table 28j is assigned to each representative color. The target H component value is a hue correction coefficient, and the target C component value is a saturation correction coefficient.

  An image based on the image data subjected to the color tone correction is displayed on the LCD monitor 34 by the video encoder 30. On the other hand, the character generator 36 OSD displays the cursor CS as a pointer on the LCD monitor 34.

  When the set key 56 is operated, the CPU 46 detects the hue of the pixel to which the cursor CS is directed (S61). The CPU 46 also identifies a reference value number assigned to two reference H component values having hues that sandwich the detected hue (S63, S65), and is assigned to the same target value number as the identified reference value number. Two target C component values are set to "0" which is a predetermined value (S65).

  The color tone of the image displayed on the LCD monitor 34 changes as the target C component value is updated. Specifically, the same color as the pixel to which the cursor CS is directed is deleted from the screen. As described above, the color tone of the display image is changed by a simple operation directed to the display image, so that the operability is improved.

  In this embodiment, the target C component value is changed to “0” in step S65, but the target C component value may be changed to a value other than “0”. In this embodiment, the target C component value is changed. Instead, the target H component value or the target L component value is changed, or the target C component value, the target H component value, and the target L component are changed. All of the component values may be changed.

  The digital camera of another embodiment is the same as the above-described embodiment except that the CPU 46 executes the subroutine shown in FIG. 14 instead of the subroutine shown in FIG. .

  Referring to FIG. 14, in step S71, the hue (H component value) of the pixel to which the cursor CS is directed is detected in the same manner as in step S61, and the detected H component value is set as the reference H component value in the reference value table 28i. The reference value number “12” is assigned. That is, the reference H component value is newly set in the reference value table 28i.

  In step S73, two reference H component values sandwiching the H component value detected in step S71 are specified, and in step S75, two reference value numbers assigned to the two specified reference H component values are detected.

  In step S77, two reference C component values corresponding to the detected two reference value numbers are read from the reference value table 28i, and a new reference C component value is created by linear interpolation of the read reference C component values. Then, the created reference C component value is assigned to the reference value number “12” of the reference value table 28i.

  In step S79, the two target H component values assigned to the same two target value numbers as the two reference value numbers detected in step S75 are read from the target value table 28j, and the linearity of the read target H component values is read. A new target H component value is created by interpolation, and the created target H component value is assigned to the target value number “12” of the target value table 28j. In step S81, the target H component value indicating “0” is assigned to the target value number “12” of the target value table 28j.

  In step S83, two reference L component values corresponding to the detected two reference value numbers are read from the reference value table 28i, and a new reference L component value is created by linear interpolation of the read reference L component values. Then, the created reference L component value is assigned to the reference value number “12” of the reference value table 28i.

  In step S85, two target L component values assigned to the same two target value numbers as the two reference value numbers detected in step S75 are read from the target value table 28j, and the linearity of the read target L component values is read. A new target H component value is created by interpolation, and the created target L component value is assigned to the target value number “12” of the target value table 28j.

  In step S87, the 13 reference values set in the reference value table 28i are sorted in the order of increasing reference H component values, and the 13 target values set in the target value table 28j are further compared with the reference value table 28i. Sort so as to ensure correspondence. When such sorting is completed, the routine returns to the upper layer routine.

  The image quality adjustment circuit 28 performs color tone correction with reference to the reference value table 28i to which the reference value is added and the target value table 28j to which the target value is added. The maximum value Nmax required for the operation of the region discriminating circuit 28f is “12” if there is one added reference value and target value, and “13” if there are two added reference values and target values. It becomes.

  The twelve reference values set from the beginning in the reference value table 28i and the twelve target values set from the beginning in the target value table 28j are distributed on the CH plane as shown in FIG. Further, the reference values corresponding to the reference value numbers “6” and “7” and the target values corresponding to the target value numbers “6” and “7” are distributed on the CH plane in the manner shown in FIG.

  If the hue of the pixel indicated by the cursor CS is Hrs, the reference H component value indicating “Hrs” is set in the reference value table 28i in step S71. In the linear interpolation in step S77, the reference C component values Cr6 and Cr7 are weighted and added according to the ratio of “Hr6-Hrs” and “Hr7-Hrs”. Thus, the reference C component value Crs is obtained. In the linear interpolation of step S79, the target H component values Ht6 and Ht7 are subjected to weighted addition according to the ratio of “Hr6-Hrs” and “Hr7-Hrs”. Thus, the target H component value Hts is obtained.

  As can be understood from the above description, the color tone of the pixel data forming the image data includes the reference values (reference H component value, reference C component value, and reference L component value) set in the reference value table 28i, and the target value table. Based on the target values (target H component value, target C component value, and target L component value) set to 28j, the image quality adjustment circuit 28 corrects the target value.

  Here, the plurality of reference values set in the reference value table 28i define the representative color. The target value set in the target value table 28j is assigned to each representative color. The target H component value is a hue correction coefficient, and the target C component value is a saturation correction coefficient.

  An image based on the image data subjected to the color tone correction is displayed on the LCD monitor 34 by the video encoder 30. On the other hand, the character generator 36 OSD displays the cursor CS as a pointer on the LCD monitor 34.

  When the set key 56 is operated, the CPU 46 detects the hue of the pixel pointed by the cursor CS, and assigns the detected hue to the new representative color as a reference H component value (S71). The CPU 46 also assigns the reference C component value and the reference L component value obtained by linear interpolation to the new representative color (S77, S83).

  The CPU 46 further specifies two representative colors sandwiching the new representative color with respect to the hue (S75). The CPU 46 also performs linear interpolation on the two target H component values respectively assigned to the two specified representative colors to create new target H component values (S79), and each of the two specified representative colors is identified. A new target L component value is created by performing linear interpolation on the two assigned target L component values (S85), and a target C component value indicating a predetermined value "0" is created. The created new target value is assigned to a new representative color. The color tone of the image displayed on the LCD monitor 34 is corrected based on the new target value. As a result, it is possible to correct the color tone of the operator's favorite color.

  In this embodiment, the tone correction is performed on the freeze image or the reproduced image, but the tone correction may be performed on the through image instead. In this case, the image quality adjustment circuit 28 needs to be provided in the signal processing circuit 22.

It is a block diagram which shows one Example of this invention. It is a block diagram which shows an example of an image quality adjustment circuit. It is an illustration figure which shows a reference value table. It is an illustration figure which shows a target value table. It is an illustration figure which shows an example of the distribution state of a reference value and a target value. It is an illustration figure which shows another example of the distribution state of a reference value and a target value. It is a flowchart which shows a part of operation | movement of an area | region discrimination circuit. It is an illustration figure which shows a part of operation | movement of FIG. 1 Example. It is an illustration figure which shows a part of other operation | movement of FIG. 1 Example. It is an illustration figure which shows the other part of operation | movement of FIG. 1 Example. It is a flowchart which shows operation | movement of CPU when performing image quality adjustment. It is a flowchart which shows another part of operation | movement of CPU when performing image quality adjustment. It is an illustration figure which shows a part of operation | movement of FIG. 1 Example. It is a flowchart which shows a part of operation | movement of the other Example of this invention. FIG. 15 is an illustrative view showing one portion of behavior of the embodiment in FIG. 14; FIG. 15 is an illustrative view showing still another portion of the operation of the embodiment in FIG. 14;

Explanation of symbols

10 ... Digital camera 14 ... Image sensor 26 ... SDRAM
28 ... Image quality adjustment circuit 32 ... LCD monitor 48 ... CPU
52 ... Image quality adjustment key

Claims (11)

Correction means for correcting the color tone of each of a plurality of pixels forming an image based on a plurality of color tone correction coefficients respectively assigned to a plurality of representative colors;
First display means for displaying an image corrected by the correction means;
Second display means for displaying a pointer on the image displayed by the first display means;
Detecting means for detecting a hue of a pixel pointed to by the pointer when receiving a first operation;
Specifying means for specifying two representative colors having hues sandwiched between hues detected by the detecting means, and updating two tone correction coefficients assigned to the two representative colors specified by the specifying means to a predetermined value An image processing apparatus comprising update means. The hue is defined by hue, saturation and brightness,
The image processing apparatus according to claim 1, wherein the tone correction coefficient is a coefficient that corrects at least one of the hue, the saturation, and the brightness. The image displayed by the first display means is a still image;
The image processing apparatus according to claim 1, wherein the second display unit moves the pointer in an arbitrary direction when a second operation is received.   4. The correction unit according to claim 1, wherein the correction unit corrects the color tone of the pixel of interest using two color tone correction coefficients respectively assigned to two representative colors having hues sandwiching the hue of the pixel of interest. 5. Image processing device. Storage means for storing a plurality of reference coefficients respectively corresponding to the plurality of representative colors;
5. The image processing apparatus according to claim 1, wherein a correction amount of the correction unit is in accordance with a difference between a plurality of reference coefficients stored in the storage unit and the plurality of tone correction coefficients. Correction means for correcting the color tone of each of a plurality of pixels forming an image based on a plurality of color tone correction coefficients respectively assigned to a plurality of representative colors;
First display means for displaying an image corrected by the correction means;
Receiving means for receiving a selection operation for selecting any pixel on the image displayed by the first display means;
An image processing apparatus comprising: a defining unit that defines a new representative color based on a hue of a pixel selected by the selection operation; and an assigning unit that allocates a new tone correction coefficient to the representative color defined by the defining unit. Further comprising second display means for displaying a pointer on the image displayed by the first display means;
The image processing apparatus according to claim 6, wherein the arbitrary pixel is a pixel directed by the pointer. Each of the plurality of tone correction coefficients includes a hue correction coefficient and a saturation correction coefficient,
The assigning means performs linear interpolation on a specifying means for specifying two representative colors sandwiching the new representative color with respect to a hue, and two hue correction coefficients respectively assigned to the two representative colors specified by the specifying means. The image processing apparatus according to claim 6, further comprising a first creation unit that creates a color correction coefficient that is applied to form the new color correction coefficient.   The image processing apparatus according to claim 8, wherein the assigning unit further includes a second creating unit that creates the new color correction coefficient and creates a saturation correction coefficient that indicates a predetermined value.   The correction unit corrects the color tone of the target pixel using two hue correction coefficients and two saturation correction coefficients respectively assigned to two representative colors having hues sandwiching the hue of the target pixel. The image processing apparatus according to 9. Storage means for storing a plurality of reference coefficients respectively corresponding to the plurality of representative colors;
The image processing apparatus according to claim 6, wherein the correction amount of the correction unit is in accordance with a difference between a plurality of reference coefficients stored in the storage unit and the plurality of tone correction coefficients.

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