JP5828632B2 - Imaging apparatus and video processing method - Google Patents

Description

  The present invention relates to a white balance correction process of an imaging apparatus.

  Conventionally, there are auto white balance, white balance set, white balance preset, and the like as white balance correction processing of an imaging apparatus. The auto white balance is automatically controlled so as to achieve an appropriate white balance based on information on image data of a subject. FIG. 7 is a flowchart showing a conventional auto white balance correction process. When the power is turned on (S180), color information for use in white balance correction processing is acquired (S182). The color information here is color information obtained by averaging the entire screen, color information of pixels included in a predetermined white extraction range, color information of the highest luminance region, and the like. Next, a white balance control value is calculated using these color information (S184). Here, when calculating the white balance control value, the color information of the pixels included in the predetermined white extraction range is given the highest priority in order to adjust the white color to the white color. Subsequently, white balance control is performed based on the calculated white balance control value (S186). After performing the above processing, it is determined whether or not photographing is continued (S188), and the processing from the white balance information acquisition processing (S182) is repeated until the power is turned off and the control is completed. When the power is turned off, the process ends (S190).

  Conventionally, in the signal processing of an imaging device, in order to provide an image quality suitable for the user's preference for each scene to be captured, as an imaging device function, an image quality filter mode used for shooting is selected from a plurality of modes. There is something to choose. In this function, the setting of the imaging device is switched in accordance with the image quality filter mode set by the user, and image quality correction is performed in accordance with each mode. As image quality correction, changes such as gradation, contrast, black balance, white balance, color balance, sharpness, soft focus, and gradation mask are performed.

JP 2006-324808 A JP 2004-134950 A

  In the image quality filter mode, for example, in order to change the impression color of the entire screen, it is possible to select a filter that applies an image quality correction effect that superimposes sepia and cold colors. However, when shooting using auto white balance as white balance correction control, the filter effect of the image quality filter mode becomes excessive due to the influence of ambient light and subject colors such as sunlight, halogen, and fluorescent light, and vice versa. There was a shortage. For example, in a filter that overlaps sepia and cold colors, the effect of the filter has become excessive when shooting subjects of similar colors. On the other hand, when shooting an object of the opposite color, the filter effect is offset and the effect is insufficient.

  As a conventional technique, there is a technique that corrects special effect processing such as grain according to the control content during photographing processing (Patent Document 1). Further, there is a technique that corrects and combines a material image to be combined with a real image according to shooting conditions and shooting conditions (Patent Document 2). However, since Patent Document 1 adds special effect processing, and Patent Document 2 applies correction processing to a material image to be synthesized, these processing are similar to auto white balance control. It cannot be applied to normal signal processing itself.

  In the present invention, in view of the above problems, in the auto white balance control when the image quality filter is applied in the imaging apparatus, the overall impression color of the entire screen finally obtained by the filter effect regardless of the ambient light or the color of the subject at the time of shooting. To be constant.

The present invention is to solve the above-described problems, and includes an imaging unit that outputs a video signal, a white balance correction unit that performs a white balance correction process on the video signal output by the imaging unit, and the white balance correction. and filtering effect processing means for applying image quality correction effect with respect to the video signal outputted by the unit, if the image quality correction effect is applied by the filter effect processing means, based on the entire screen color information before SL video signal Control means for controlling the white balance correction means so that the correction is prioritized over the correction based on the color information of a part of the screen of the video signal .

  According to the present invention, it is possible to make the impression color of the entire screen finally obtained by the filter effect constant regardless of the ambient light at the time of shooting or the color of the subject.

It is a schematic block diagram which shows the structure of the imaging device in embodiment of this invention. 1 is a perspective view illustrating an overview of an imaging apparatus according to an embodiment of the present invention. It is a flowchart which shows the white balance correction process of 1st Embodiment. 6 is a flowchart illustrating white balance control value calculation processing at the normal time of the imaging apparatus according to the first embodiment. 6 is a flowchart illustrating white balance control value calculation processing at the time of image quality filter effect of the imaging apparatus according to the first embodiment. It is a flowchart which shows the white balance correction process of 2nd Embodiment. It is a flowchart which shows the conventional white balance correction process.

  Embodiments according to the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing the configuration of the present embodiment.

  Reference numeral 101 denotes a lens, and a diaphragm 102 is disposed behind the lens 101. The light passing through the lens 101 and the diaphragm 102 is imaged as a subject image on the image forming surface of the image sensor 105. In the image sensor 105, the formed subject image is converted from an optical signal to a video signal.

  The video signal obtained by the image sensor 105 is sent to the signal processing unit 110. The camera microcomputer 111 controls the operation of each processing block of the signal processing unit 110. In the signal processing unit 110, the white balance correction unit 107 performs white balance correction processing on the video signal in accordance with this control. Further, when the image quality filter mode is selected by the user, the camera microcomputer 111 sets the image quality filter mode selected by the user in the filter effect processing unit 108. The filter effect processing unit applies an image quality correction effect to the video signal in accordance with the set mode. Here, the image quality correction effect processing includes gamma conversion, black balance correction, white balance correction, color balance correction, edge enhancement, soft focus effect, and the like.

  After signal processing is performed in the signal processing unit 110, the video signal is output to the display 116, or recorded on the magnetic tape 115, the DVD disk 117, or the memory card 118.

  A color information detection unit 114 first divides an image in the horizontal and vertical directions, sets a plurality of color information detection frames (block images of a predetermined size), and uses the following three detection methods to perform color detection. Detect information. That is, with respect to the pixels in the color information detection frame, the luminance data and the color data are integrated within only pixels that are within a preset threshold range and can be regarded as white, thereby detecting white data for each color information detection frame. . In addition, the color information is detected using the integration result of the detection frame that is the highest luminance region in the screen. Further, the average value of the color information of all the pixels in the screen is detected by using the integration result of the pixels in all or substantially all the detection frames. Various color information detected by the color information detection unit 114 is sent to the camera microcomputer 111. The camera microcomputer 111 calculates the white balance control value using the acquired color information of the pixels included in the predetermined white extraction range, the color information of the highest luminance region, and the color information obtained by averaging the entire screen. The camera microcomputer 111 sets the control value in the white balance correction unit 107, and the white balance correction unit 107 performs white balance correction processing based on the set white balance control value. The white balance correction process in the white balance correction unit 107 will be described in detail later. Further, processes other than the white balance correction process, the image quality correction effect process, and the color information detection process in the signal processing unit 110 are not shown here.

  Further, the camera microcomputer 111 performs control such as accumulation and reading of the image sensor 105 through the image sensor control unit 106. In addition, the lens control unit 103 performs control such as focusing and zooming of the lens 101. Further, using the luminance information of the subject obtained from the image data obtained from the image sensor 105, the aperture 102 is controlled through the aperture controller 104, and the shutter speed is controlled through the image sensor controller 106. Then, exposure control is performed. Further, the camera shake at the time of photographing of the user is corrected by driving the lens 101 through the lens control unit 103 or by controlling the signal processing unit 110.

  FIG. 2 is a perspective view showing an overview of the imaging apparatus of the present embodiment. Reference numeral 120 denotes an imaging apparatus main body. Recording media such as a DVD disk 117, a magnetic tape 115, and a memory card 118 are accommodated inside the imaging apparatus main body 120 so that video signals and still images can be recorded and reproduced. Reference numeral 121 denotes a lens unit that houses the lens 101 of FIG. Reference numeral 122 denotes a microphone, which is provided for recording sound during shooting. An electronic viewfinder (EVF) 123 corresponding to the display 116 in FIG. 1 is provided for aiming and confirming a subject when taking a picture by looking into the camera.

  Reference numeral 124 denotes a moving image trigger switch. The moving image trigger switch 124 is a push button, and is a switch operated by a user in order to transmit moving image shooting start and end to the camera microcomputer 111. Reference numeral 125 denotes a still image trigger switch. The still image trigger switch 125 is a push button, and is a switch operated by the user to transmit the start and end of still image shooting to the camera microcomputer 111. A mode dial 126 is composed of a rotary switch. The mode dial 126 can select, for example, “playback” to be set to the playback mode, “camera” to be set to the camera mode, or “OFF” which is neither of them, and the selection output is transmitted to the camera microcomputer 111.

  Reference numeral 127 denotes a group of operation switches, such as a key for inputting a white balance mode, a key for inputting an image quality filter mode, and other menu operations and playback system operations for the user to operate the main body. The key for is arranged. The camera microcomputer 111 performs white balance correction, image quality filter setting, and the like in accordance with signals input from these keys.

  A liquid crystal panel 128 is attached to the side of the main body so as to be freely opened and closed, and corresponds to the display 116 shown in FIG. 1 like the EVF 123, and is mainly used for checking a subject image during camera shooting and displaying a reproduced image during playback. Is done. The liquid crystal panel 128 can be rotated in the horizontal direction while being opened from the main body 120. Reference numeral 129 denotes a speaker, which is provided for outputting sound when reproducing. A battery 130 is detachable from the main body 120.

  Next, white balance correction processing by the camera microcomputer 111 in the imaging apparatus of the present embodiment will be described with reference to the flowchart of FIG.

  FIG. 3 is a flowchart showing the auto white balance correction process of the present embodiment. When the power is turned on (S101), the camera microcomputer 111 acquires color information for use in white balance correction processing by the color information detection unit 114 (S103). The color information here is color information obtained by averaging the entire screen, color information of pixels included in a predetermined white extraction range, color information of the highest luminance region, and the like.

  Next, it is determined whether or not the image quality filter mode is set (S105). In the case of the image quality filter mode, the camera microcomputer 111 calculates a white balance control value at the time of the image quality filter effect using the acquired color information (S107). Here, when calculating the white balance control value, in order to keep the impression color of the entire screen constant, priority is given to color information obtained by averaging the entire screen. Further, the white balance control value is calculated using the white balance convergence point at the time of the image quality filter effect. The white balance control value calculation process at the time of the image quality filter effect will be described in detail later. Next, the camera microcomputer 111 performs white balance control based on the calculated white balance control value (S109). Subsequently, the camera microcomputer 111 performs image quality filter effect processing according to the image quality filter mode selected by the user by the filter effect processing unit 108 (S110). Here, the image quality filter effect processing includes gamma conversion, black balance correction, white balance correction, color balance correction, edge enhancement, soft focus effect, and the like.

  On the other hand, when the image quality filter mode is not set, following the white balance information acquisition process (S103), the camera microcomputer 111 calculates a normal white balance control value using the acquired color information (S112). Here, when calculating the white balance control value, the color information of the pixels included in the predetermined white extraction range is given the highest priority in order to adjust the white color to the white color. Further, the white balance control value is calculated using the normal white balance convergence point. The normal white balance control value calculation process will be described in detail later. Next, the camera microcomputer 111 performs white balance correction control based on the calculated white balance control value (S114).

  After performing the above processing, it is determined whether or not photographing is continued (S116), and the processing from the white balance information acquisition processing (S103) is repeated until the power is turned off and the control is completed. When the power is turned off, the process ends (S118).

  Next, the normal white balance control value calculation process (S112) will be described with reference to the flowchart of FIG.

  FIG. 4 is a flowchart showing white balance control value calculation processing in a normal state of the present embodiment. When the white balance control value calculation process is started (S120), the camera microcomputer 111 first calculates a normal white balance convergence point (S122). At this time, a white balance convergence point is obtained so that white matches white using information such as color temperature and brightness at the time of shooting.

  Subsequently, the camera microcomputer 111 compares the color information of the pixels included in the predetermined white extraction range with the white balance convergence range centered on the white balance convergence point (S124). When the color information of the pixel is within the white balance convergence range, the current white balance control value is not updated, and the white balance control value calculation process is terminated (S134).

  On the other hand, if the color information of the pixel is not within the white balance convergence range, the camera microcomputer 111 compares the color information of the highest luminance region with the white balance convergence range centered on the white balance convergence point (S126). If the color information of the highest luminance region is within the white balance convergence range, the white balance control value calculation process is terminated without updating the current white balance control value (S134).

  On the other hand, when the color information of the highest luminance region is not within the white balance convergence range, the camera microcomputer 111 compares the color information obtained by averaging the entire screen with the white balance convergence range centered on the white balance convergence point ( S128). When the color information obtained by averaging the entire screen is within the white balance convergence range, the current white balance control value is not updated and the white balance control value calculation process is terminated (S134).

  On the other hand, if the color information obtained by averaging the entire screen is not within the white balance convergence range, the process proceeds to step S130. Then, the camera microcomputer 111 selects the color information closest to the white balance convergence point among the color information of the pixels included in the predetermined white extraction range, the color information of the highest luminance region, and the color information obtained by averaging the entire screen. Subsequently, the camera microcomputer 111 calculates a white balance control value so that the selected color information approaches the white balance convergence point, updates the value (S132), and ends the white balance control value calculation process (S134). ). With the above processing, in the normal white balance control value calculation processing, the color information of the pixels included in the predetermined white extraction range is given the highest priority in order to adjust white to white.

  Next, the white balance control value calculation process (S107) at the time of image quality filter effect will be described with reference to the flowchart of FIG.

  FIG. 5 is a flowchart showing white balance control value calculation processing at the time of image quality filter effect of the present embodiment. When the white balance control value calculation process is started (S140), the camera microcomputer 111 first calculates a white balance convergence point at the time of image quality filter effect (S142). At this time, the white balance convergence point is obtained by using information such as color temperature and brightness at the time of photographing so as not to impair sepia and cold colors, which are filter effects. For example, when a cold color effect is applied, the effect is shifted slightly in the blue direction from the white convergence point in the normal mode.

  Subsequently, the camera microcomputer 111 compares the color information obtained by averaging the entire screen with the white balance convergence range centered on the white balance convergence point (S144). When the color information obtained by averaging the entire screen is within the white balance convergence range, the current white balance control value is not updated, and the white balance control value calculation process ends (S154).

  On the other hand, if the color information obtained by averaging the entire screen is not within the white balance convergence range, the camera microcomputer 111 determines the color information of the pixels included in the predetermined white extraction range and the white balance centered on the white balance convergence point. The convergence range is compared (S146). If the color information of the pixel is within the white balance convergence range, the current white balance control value is not updated, and the white balance control value calculation process ends (S154).

  On the other hand, if the color information of the pixel is not within the white balance convergence range, the camera microcomputer 111 compares the color information of the highest luminance region with the white balance convergence range centered on the white balance convergence point (S148). If the color information of the highest brightness region is within the white balance convergence range, the white balance control value calculation process is terminated without updating the current white balance control value (S154).

  On the other hand, if the color information of the highest luminance region is not within the white balance convergence range, the process proceeds to step S150. Then, the camera microcomputer 111 selects the color information obtained by averaging the entire screen, the color information of the pixels included in the predetermined white extraction range, and the color information of the highest luminance region, the one closest to the white balance convergence point. Subsequently, the camera microcomputer 111 calculates a white balance control value so that the selected color information approaches the white balance convergence point, updates the value (S152), and ends the white balance control value calculation process (S154). ). By the above processing, in the white balance control value calculation processing at the time of the image quality filter effect, the color information obtained by averaging the entire screen has the highest priority in order to keep the impression color of the entire screen constant.

  Here, the case where the color information of the highest luminance region is used in the white balance control value calculation processing at the time of the image quality filter effect has been described. In addition to this, in order to keep the impression color of the entire screen constant, the color information of the highest luminance region that is easily influenced by the ambient light or the color of the subject may be ignored. In this case, the white balance control value may be calculated using only color information obtained by averaging the entire screen and color information of pixels included in a predetermined white extraction range.

  As described above, in the present embodiment, the signal and algorithm used for auto white balance control are switched between when the image quality effect is applied and when the image quality effect is not applied. Thereby, in the auto white balance control when the image quality filter is applied in the image pickup apparatus, the impression color of the entire screen finally obtained by the filter effect is made constant regardless of the ambient light at the time of shooting and the color of the subject. It becomes possible.

(Second Embodiment)
In the present embodiment, the white balance correction process by the camera microcomputer 111 in the imaging apparatus of the first embodiment is replaced as follows.

  A white balance correction process performed by the camera microcomputer 111 in the imaging apparatus of the present embodiment will be described with reference to the flowchart of FIG.

  FIG. 6 is a flowchart showing the auto white balance correction process of the present embodiment. When the power is turned on (S201), the camera microcomputer 111 acquires color information for use in white balance correction processing by the color information detection unit 114 (S203). The color information here is color information obtained by averaging the entire screen, color information of pixels included in a predetermined white extraction range, color information of the highest luminance region, and the like.

  Next, it is determined whether or not the image quality filter mode is set (S205). In the case of the image quality filter mode, the camera microcomputer 111 determines whether the image quality filter effect in the image quality filter mode selected by the user uses at least one of black balance shift and white balance shift (S206). Here, the black balance shift and the white balance shift are processes for shifting an appropriate white balance gain value by a predetermined amount for red or blue in order to add color to the entire screen.

  When the black balance shift or white balance shift effect is not used, following the white balance information acquisition process (S203), the camera microcomputer 111 uses the acquired color information to obtain a normal white balance control value. Calculate (S220). Here, when calculating the white balance control value, the color information of the pixels included in the predetermined white extraction range is given the highest priority in order to adjust the white color to the white color. Further, the white balance control value is calculated using the normal white balance convergence point. Next, the camera microcomputer 111 performs white balance correction processing based on the calculated white balance control value (S222). Subsequently, the camera microcomputer 111 performs image quality filter effect processing according to the image quality filter mode selected by the user by the filter effect processing unit 108 (S224). Here, the image quality filter effect processing includes gamma conversion, color balance correction, edge enhancement, soft focus effect, and the like.

  On the other hand, if it is determined in step S206 that at least one effect of black balance shift and white balance shift is used, the process proceeds to step S207. Then, the camera microcomputer 111 calculates a white balance control value at the time of image quality filter effect using the acquired color information. Here, when calculating the white balance control value, in order to keep the impression color of the entire screen constant, priority is given to color information obtained by averaging the entire screen. Further, the white balance control value is calculated using the white balance convergence point at the time of the image quality filter effect. Next, the camera microcomputer 111 performs white balance correction processing based on the calculated white balance control value (S209). Subsequently, the camera microcomputer 111 performs image quality filter effect processing according to the image quality filter mode selected by the user by the filter effect processing unit 108 (S210). Here, the image quality filter effect processing includes gamma conversion, black balance correction, white balance correction, color balance correction, edge enhancement, soft focus effect, and the like.

  On the other hand, in the image quality filter mode determination in step S205, if the image quality filter mode is not set, following the white balance information acquisition process (S203), the camera microcomputer 111 uses the acquired color information to obtain a normal white balance control value. Calculate (S212). Here, when calculating the white balance control value, the color information of the pixels included in the predetermined white extraction range is given the highest priority in order to adjust the white color to the white color. Further, the white balance control value is calculated using the normal white balance convergence point. Next, the camera microcomputer 111 performs white balance correction processing based on the calculated white balance control value (S214).

  After performing the above processing, it is determined whether or not photographing is continued (S216), and the processing from the white balance information acquisition processing (S203) is repeated until the power is turned off and the control is completed. When the power is turned off, the process ends (S218).

  As described above, in the present embodiment, when some image quality effects are easily affected by the ambient light and the subject color at the time of shooting, and when another image quality effect is applied and when no image quality effect is applied. To switch the signal and algorithm used for auto white balance control. Thereby, in the auto white balance control when the image quality filter is applied in the image pickup apparatus, the impression color of the entire screen finally obtained by the filter effect is made constant regardless of the ambient light at the time of shooting and the color of the subject. It becomes possible.

DESCRIPTION OF SYMBOLS 101 Lens 102 Diaphragm 103 Lens control part 104 Aperture control part 105 Image sensor 106 Image sensor control part 107 White balance correction part 108 Filter effect processing part 110 Signal processing part 111 Camera microcomputer 114 Color information detection part 115 Magnetic tape 116 Display 117 DVD disk 118 Memory Card 120 Imaging Device Main Body 121 Lens Unit 122 Microphone 123 Electronic Viewfinder (EVF)
124 Trigger switch for moving image 125 Trigger switch for still image 126 Mode dial 127 Operation switch group 128 Liquid crystal panel 129 Speaker 130 Battery

Claims (7)

Imaging means for outputting a video signal;
White balance correction means for performing white balance correction processing of the video signal output by the imaging means;
Filter effect processing means for applying an image quality correction effect to the video signal output by the white balance correction means;
Wherein the image quality correction effect by the filtering effect processing means is applied, as before Symbol correction based on the entire screen of the color information of the video signal takes precedence over correction based on the screen part of the color information of the video signal An image pickup apparatus comprising: control means for controlling the white balance correction means. Wherein, in a case where the image quality correction effect as the image quality correction effect is applied is not applied, the imaging apparatus according to claim 1, characterized in that switching the convergence point of the white balance control. Wherein, if the image quality correction effect can be applied is carried out with priority correction to keep the impression color of the entire screen to be constant, if the image quality correction effect can not apply adjust the white video signal to a predetermined white The imaging apparatus according to claim 1 , wherein the white balance correction unit is controlled so that correction is performed with priority. When the image quality correction effect is applied, the control means obtains a control value of the white balance correction means by giving priority to color information obtained by averaging the entire screen, and when the image quality correction effect is not applied, a predetermined white extraction is performed. The imaging apparatus according to claim 1, wherein the control value of the white balance correction unit is obtained with priority given to color information of pixels included in the range. 5. The control unit according to claim 1, wherein when the image quality correction effect is applied, the control unit obtains a control value of the white balance correction unit without using color information of a pixel having the highest luminance. The imaging device described in 1. The imaging apparatus according to claim 1, wherein the image quality correction effect is an image quality correction effect using at least one of a black balance shift and a white balance shift. A white balance correction step for performing white balance correction processing of the video signal output by the imaging means;
A filter effect processing step of applying an image quality correction effect to the video signal output by the white balance correction step;
When said filter effect processing steps by the image quality correction effect is applied, as before Symbol correction based on the entire screen of the color information of the video signal takes precedence over correction based on the screen part of the color information of the video signal And a control step for controlling the white balance correction step.

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