JP2011130370A - Imaging apparatus and imaging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable both signal processing according to a photographing scene and smooth connection of a plurality of photographing scenes. <P>SOLUTION: An imaging apparatus includes an imaging module for photographing a subject and outputting a video signal, a signal processing module for processing the video signal output from the imaging module, a discrimination module for discriminating the photographing scenes for the video signals issued from the imaging module, and a control module for controlling the signal processing module in such a manner that the video signals are subjected to signal processing according to the photographing scenes discriminated by the discrimination module. When a control range is provided or an image quality correction target value upon image quality correction of the video signal and signal processing module control is controlled to perform the signal processing in the control range, image quality correction can be automatically carried out according to the photographing scene, while avoiding an excessively large change upon switching of scene discrimination or avoiding a trouble upon erroneous detection. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and an imaging method, and more particularly to a technique suitable for use in image quality correction of an imaging apparatus.

  In the signal processing of the imaging apparatus, appropriate image quality correction differs for each scene to be shot. For this reason, as a function of the imaging device, the user selects a scene mode used for shooting from a plurality of modes, switches the setting of the imaging device according to the scene mode set by the user, and corrects the image quality suitable for each mode. It is carried out.

  As a conventional technique, a sunset mode can be set, WB adjustment is performed with adjustment values having different characteristics, a plurality of sample images having different hues are generated and displayed to the user, and desired image processing is performed based on the sample images. Can be selected (Patent Document 1).

  Further, as a conventional technique, the sunrise time data of the shooting location is obtained based on the position information by GPS. Then, when it is within a predetermined time before and after the sunrise sunset time, it is estimated that it is affected by the sunset or the sunrise, and the effect of white balance adjustment is weakened (Patent Document 2).

JP 11-298848 A JP 2001-39739 A

  However, as proposed in Patent Document 1, switching to an appropriate scene mode according to a shooting scene is also a troublesome operation for a user, and it is difficult for a beginner to determine an appropriate mode or image. It is. Further, the technique proposed in Patent Document 2 has a problem in that it does not take into account a change in image quality or an adverse effect upon erroneous detection or scene switching.

Furthermore, if the same level of correction is applied as in the conventional scene mode sunset, in the case of automatic detection, the change will become too large due to the switching of scene discrimination, and the adverse effects of false detection will also increase. There was a problem.
SUMMARY OF THE INVENTION In view of the above-described problems, the present invention has an object to make it possible to simultaneously perform signal processing according to a shooting scene and to smoothly connect a plurality of shooting scenes. To do.

  An imaging apparatus according to the present invention includes an imaging unit that captures a subject and outputs a video signal, a signal processing unit that processes a video signal output from the imaging unit, and a video signal output from the imaging unit Determining means for determining a scene; and control means for controlling the signal processing means so as to perform signal processing on the video signal in accordance with the shooting scene determined by the determining means. A control range is provided for an image quality correction target value when image quality correction is performed on the video signal, and the signal processing means is controlled to perform signal processing in the control range.

  According to the present invention, when a shooting scene is determined and signal processing corresponding to the shooting scene is performed on a video signal, a range is provided for the image quality correction value, and the image quality correction is performed using the image quality correction value within the range. Changed the state. As a result, it is possible to reduce the change caused by the switching of the scene discrimination and the adverse effect at the time of erroneous detection, and to achieve both the effect of the image quality correction and the smooth connection of the shooting scene.

1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention. It is a perspective view which shows the external appearance of an imaging device. It is explanatory drawing which shows a white balance control range. It is a flowchart explaining a scene determination process. It is a flowchart which shows 1st Embodiment and demonstrates evening scene processing. It is a flowchart which shows 2nd Embodiment and demonstrates evening scene processing. It is a flowchart which shows 3rd Embodiment and demonstrates evening scene processing.

(First embodiment)
Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus 100 according to the present embodiment.
In FIG. 1, reference numeral 101 denotes a lens, and a diaphragm 102 is disposed behind the lens 101. The light that has passed through the lens 101 and the diaphragm 102 is formed as a subject image on the image formation surface of the image sensor 105. The subject image formed on the image sensor 105 is converted from an optical signal to a video signal by the image sensor 105.

  The video signal obtained by the image sensor 105 is sent to the signal processing unit 112. The video signal is subjected to white balance correction processing by the white balance correction processing unit 107 and color correction processing by the color correction processing unit 108 in the signal processing unit 112. Thereafter, the data is output to the display 116 or recorded on the magnetic tape 115, the DVD disk 117, or the memory card 118. The camera information detection unit 110 detects camera information such as luminance and color and sends the detected camera information to the camera microcomputer 111. Although other processing is performed in the signal processing unit 112, detailed description thereof is omitted here.

  The camera microcomputer 111 determines a shooting scene from camera information such as luminance and color obtained from the camera information detection unit 110. Further, a white balance correction value and a color enhancement correction value are calculated based on the determined scene. Then, by setting the calculated white balance correction value in the white balance correction processing unit 107, white balance control for capturing a video is performed, and processing is performed so that the white balance of the video is appropriate. Further, by setting the calculated color enhancement correction value in the color correction processing unit 108, color correction of the video is performed, and processing is performed so that the color reproducibility of the video becomes appropriate. The white balance correction process and the color enhancement correction process for the determined shooting scene, such as the scene determination process by the camera microcomputer 111 and the sunset scene, will be described in detail later.

  In addition to the above-described control, 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, the aperture 102 is controlled through the aperture controller 104 using the luminance information of the subject obtained from the image data obtained from the image sensor 105. Further, exposure control is performed by controlling the shutter speed through the image sensor control unit 106. 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 112.

FIG. 2 is a perspective view illustrating an overview of the imaging apparatus 100 according to the embodiment.
In FIG. 2, reference numeral 120 denotes an imaging apparatus main body. A recording medium such as a DVD disk, a magnetic tape, and a memory card is accommodated in 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. Reference numeral 122 denotes a microphone, which is provided for recording sound during shooting. Reference numeral 123 denotes an electronic viewfinder (EVF), which is provided for aiming and confirming a subject at the time of camera shooting when the user looks into the camera.

  Reference numeral 124 denotes a moving image trigger switch. The moving image trigger switch 124 is configured by a push button, and is a switch operated by the user to transmit the moving image shooting start and end to the imaging apparatus 100. 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 device.

  A mode dial 126 is composed of a rotary switch. The mode dial 126 can select, for example, “reproduction” to be set to the reproduction mode, “camera” to be set to the camera mode, and “OFF” which is none of them. Reference numeral 127 denotes a group of operation switches on which keys for inputting a white balance mode and other menu operations and playback system operations are arranged so that the user operates the main body. In the present embodiment, shooting scenes that can be set and input by the user are an evening scene, a night scene, a spotlight, a person, a landscape, a blue sky, vivid, and backlight. The white balance target value differs for each shooting scene.

  Reference numeral 128 denotes a liquid crystal panel attached to the side of the main body so as to be freely opened and closed. Like the EVF 123, the liquid crystal panel 128 is mainly used for confirming a subject image during camera shooting and for displaying a reproduced image during reproduction. The liquid crystal panel 128 can be rotated in the horizontal direction while being opened from the imaging apparatus main body 120. Reference numeral 129 denotes a speaker, which is provided for outputting sound when reproducing. A battery 130 is detachable from the imaging apparatus main body 120.

Next, scene determination processing performed by the camera microcomputer 111 in the imaging apparatus 100 of the present embodiment will be described with reference to the flowchart of FIG.
FIG. 4 is a flowchart illustrating the scene determination process according to the present embodiment. When the power is turned on, the camera microcomputer 111 starts scene determination (S40). When the scene determination is started, it is first determined whether it is an evening scene (S41). If the result of this determination is that there is no evening scene, the process proceeds to S46 to clear the evening scene counter Csu, and then the scene determination is set to “normal” (S47).

  On the other hand, if the determination result in S41 is an evening scene, the evening scene counter Csu is incremented (S42). Next, it is determined whether or not the value of Csu is larger than a predetermined value N set in advance (S43). If the result of this determination is greater than the predetermined value N, the scene determination is changed from the previous scene determination result, and the scene determination is “Evening” (S44). If Csu is equal to or smaller than the predetermined value N, the scene determination is not changed, the previous scene determination result is maintained, and the scene determination is “normal” (S47). This is to improve the reliability and stability of the scene determination. The scene determination is changed only after the same determination is continued more than N times.

  If the scene determination is “Evening” in S44, the white balance correction processing unit 107 and the color correction processing unit 108 perform an appropriate evening scene process for the evening scene (S45). On the other hand, if the scene determination is “normal” in S47, normal processing is performed (S48). The above determination process is repeated until the end of shooting.

Next, sunset scene processing performed by the camera microcomputer 111 in the imaging apparatus 100 of the present embodiment will be described with reference to the explanatory diagram of FIG. 3A and the flowchart of FIG.
FIG. 3A is an explanatory diagram showing the white balance control range of the present embodiment. The range surrounded by the reference numeral 150, the reference numeral 152, the low color temperature side white balance control range 145, and the high color temperature side white balance control range 147 is white after state transition with respect to the white balance gain target value (image quality correction target value). This is the balance control range. The white balance gain target value in the present embodiment is assumed to be the same as the target value of the shooting scene that can be set and input using the key for the user to input the white balance mode as described above.

FIG. 5 is a flowchart for explaining sunset scene processing according to this embodiment.
If it is determined that the scene is an evening scene, the camera microcomputer 111 starts the evening scene process (S50).
When the processing is started, first, a white balance gain value before being determined as the current sunset scene is acquired (S51). In FIG. 3A, reference numeral 141 or reference numeral 142 represents a white balance gain value before being determined as an evening scene.

  Subsequently, the white balance gain value after the state transition is calculated (S52). At this time, the white balance gain value after the state transition is directed to the white balance target value 143 of the evening scene. Then, the white balance gain value closest to the white balance gains 141 and 142 before the transition to the sunset scene is determined within the white balance control range shown in FIG. In other words, in the present embodiment, when the user directly inputs a setting of a shooting scene, the white balance gain value goes toward the white balance target value 143 of the evening scene without limitation. On the other hand, in the evening scene in the automatic scene determination, the white balance gain value is limited on the low color temperature side white balance control range 145 or the high color temperature side white balance control range 147. The position on the control range is not limited to the white balance gain value closest to the white balance gains 141 and 142. For example, the value of the intersection of the straight line connecting the white balance gains 141 and 142 and the white balance gain target value and the white balance control range 145 or the high color temperature side white balance control range 147 may be used.

  In this example, when the target values are A, red gain (Rgain), and blue gain (Bgain), they are determined as A (Rgain = R1, Bgain = B1). Subsequently, the white balance correction processing unit 107 updates the white balance gain value and corrects the white balance appropriate for the evening scene (S53).

  As described above, in the imaging apparatus 100 according to the present embodiment, when a shooting scene is determined and signal processing corresponding to the shooting scene is performed on a video signal, a range is provided for the image quality correction value. The state is changed by performing image quality correction according to the image quality correction value. As a result, it is possible to reduce changes in scene discrimination switching, such as state transitions to the sunset scene, and adverse effects in the case of false detection, and to achieve both the effects of image quality correction and the smooth connection of the shooting scene. It becomes possible to make it. In the present embodiment, the shooting scene determined by the imaging apparatus 100 according to the present embodiment is at least one of an evening scene, a night scene, a spotlight, a person, a landscape, a blue sky, vivid, and backlight.

(Second Embodiment)
In the present embodiment, evening scene processing by the camera microcomputer 111 in the imaging apparatus 100 in the first embodiment is performed as follows.
Hereinafter, sunset scene processing by the camera microcomputer 111 in the imaging apparatus 100 of the present embodiment will be described with reference to the explanatory diagram of FIG. 3B and the flowchart of FIG.

FIG. 3B is an explanatory diagram showing the white balance control range of the present embodiment.
In FIG. 3B, the range surrounded by reference numerals 150 and 152, the low color temperature side white balance control range 155, and the high color temperature side white balance control range 157 is the white balance control range after the state transition. . The low color temperature side white balance control range 155 and the high color temperature side white balance control range 157 are not fixed values but change according to the white balance gain value before the state transition.

FIG. 6 is a flowchart for explaining sunset scene processing according to this embodiment.
If it is determined that the scene is an evening scene, the camera microcomputer 111 starts the evening scene process (S60).
First, a white balance gain value wb before being determined as the current sunset scene is acquired (S61). In FIG. 3B, reference numerals 141 and 142 represent white balance gain values before being determined as an evening scene.

  Next, it is determined whether the white balance gain value wb before being determined as an evening scene is smaller than a preset threshold value Th_1 (S62). If the result of this determination is smaller than the threshold value Th_1, the low color temperature side white balance control range 155 is shifted to the low color temperature side (S63), and the process proceeds to the next step S66.

  If the result of the determination in S62 is that the white balance gain value wb before being determined as an evening scene is equal to or greater than the threshold Th_1, the white balance gain value wb prior to being determined as an evening scene is greater than a preset threshold Th_h. Is determined (S64). If the result of this determination is that it is greater than the threshold value Th_h, the high color temperature side white balance control range 157 is shifted to the high color temperature side (S65), and the process proceeds to the next step S66. In S64, if the white balance gain value wb before being determined to be an evening scene is equal to or less than the threshold Th_h, the process proceeds to the next step S66 as it is.

  In S66, the white balance gain value after the state transition is calculated. At this time, the white balance gain value after the state transition is directed to the white balance target value 143 of the evening scene. In addition, the white balance gain value that is closest to the white balance gain 141 or 142 before the transition to the sunset scene is determined within the white balance control range shown in FIG. Subsequently, the white balance correction processing unit 107 updates the white balance gain value and corrects the white balance appropriate for the evening scene (S67). Thereafter, end processing is performed in S68.

  As described above, in this embodiment, when the white balance gain value before the transition to the sunset scene is lower than the preset color temperature, the range of possible white balance gain values in the sunset scene is set. Shift to low color temperature. On the contrary, when the white balance gain value before the transition to the sunset scene is higher than the preset color temperature, the possible range of the white balance gain value in the sunset scene is shifted to the high color temperature side.

  By performing such correction processing, it is not affected by the state of the white balance before the state transition. Can be reduced. As a result, it is possible to achieve both the effect of image quality correction and the smooth connection of the shooting scene.

(Third embodiment)
Hereinafter, sunset scene processing by the camera microcomputer 111 in the imaging apparatus 100 of the present embodiment will be described with reference to the flowchart of FIG.

FIG. 7 is a flowchart for explaining sunset scene processing according to this embodiment.
If it is determined that the scene is an evening scene, the camera microcomputer 111 starts the evening scene process (S70).

  When the process is started, first, a white balance gain value wb before being determined as the current sunset scene is acquired (S71). Subsequently, the white balance gain value wb ′ after the state transition is calculated (S72). Subsequently, the white balance correction processing unit 107 updates the white balance gain value and corrects the white balance appropriate for the evening scene (S73).

  Next, a color enhancement correction value is calculated according to the difference (wb′−wb) in white balance gain before and after the transition to the sunset scene (S74). Here, the smaller the white balance gain difference (wb'-wb) before and after the transition to the sunset scene, the larger the correction value for the color enhancement correction. Conversely, the white balance gain before and after the transition to the sunset scene. The larger the difference is, the smaller the color enhancement correction value is.

At this time, the white balance in the sunset scene is set so that the product of the color effect by the white balance gain correction and the color effect by the color enhancement correction before and after the transition to the sunset scene is within a preset range. The gain value and the color enhancement correction value may be determined.
Subsequently, the color correction processing unit 108 updates the color enhancement correction value and performs color enhancement correction appropriate for the evening scene (S75). Thereafter, end processing is performed (S76).

  As described above, the smaller the white balance gain difference before and after the transition to the sunset scene, the larger the correction value of the color enhancement correction, and conversely, the white balance gain difference before and after the transition to the sunset scene. The larger the value, the smaller the color enhancement correction value. By processing in this way, it is possible to keep the effect of color correction when transitioning to a sunset scene constant, and to reduce changes caused by switching scene discrimination and adverse effects during false detection. it can. Thereby, also in this embodiment, it is possible to achieve both the effect of the image quality correction and the smooth connection of the shooting scene.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (computer program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various computer-readable storage media. Then, the computer (or CPU, MPU, etc.) of the system or apparatus reads out and executes the program.

101 Lens, 102 Aperture, 103 Lens Control Unit, 104 Aperture Control Unit, 105 Image Sensor, 106 Image Sensor Control Unit, 107 White Balance Correction Processing Unit, 108 Color Correction Processing Unit, 110 Camera Information Detection Unit, 111 Camera Microcomputer, 112 Signal processing unit, 115 magnetic tape, 116 display, 117 DVD disk, 118 memory card

Claims (12)

Imaging means for photographing a subject and outputting a video signal;
Signal processing means for signal processing the video signal output from the imaging means;
Discriminating means for discriminating a shooting scene of the video signal output from the imaging means;
Control means for controlling the signal processing means to perform signal processing on the video signal according to the shooting scene determined by the determination means,
The image pickup apparatus characterized in that the control means provides a control range for an image quality correction target value when image quality correction is performed on the video signal, and controls the signal processing means to perform signal processing in the control range.   The imaging apparatus according to claim 1, wherein the shooting scene determined by the determining unit is at least one of an evening scene, a night scene, a spotlight, a person, a landscape, a blue sky, a bright, and a backlight.   The imaging apparatus according to claim 1, wherein the image quality correction target value is at least one of a white balance gain value and a color enhancement correction value.   The control means provides a control range for a white balance gain target value in the sunset scene, and the white balance gain value closest to the white balance gain before the transition to the sunset scene is made in the control range. The imaging apparatus according to claim 2 or 3, wherein the balance is shifted.   The image pickup apparatus according to claim 4, wherein the control unit changes a correction value for color enhancement correction according to a difference in white balance gain before and after transition to the evening scene.   The control means increases the correction value of the color enhancement correction as the difference in white balance gain before and after transition to the sunset scene is smaller, and conversely as the difference in white balance gain increases. 6. The imaging apparatus according to claim 5, wherein a correction value for correction is reduced.   7. The control unit according to claim 4, wherein the range of the white balance gain value in the evening scene can be changed according to the white balance gain value before the transition to the evening scene. The imaging device according to item.   When the white balance gain value before the transition to the evening scene is lower than the preset color temperature, the control means shifts the range that the white balance gain value in the evening scene can take to the low color temperature side. On the other hand, if the white balance gain value before the transition to the sunset scene is higher than the preset color temperature, the possible range of the white balance gain value in the sunset scene is shifted to the high color temperature side. The imaging apparatus according to claim 7.   The control means controls the white balance in the sunset scene so that the product of the color effect by the white balance gain correction and the color effect by the color enhancement correction before and after the transition to the sunset scene falls within a preset range. The imaging apparatus according to claim 4, wherein a gain value and a color enhancement correction value are determined. An imaging process of shooting a subject and outputting a video signal;
A signal processing step for signal processing the video signal output from the imaging step;
A determination step of determining a shooting scene of the video signal output from the imaging step;
A control step for controlling the signal processing step so as to perform signal processing on the video signal according to the shooting scene determined in the determination step;
The imaging method according to claim 1, wherein a control range is provided for an image quality correction target value when image quality correction is performed on the video signal, and the signal processing step is controlled to perform signal processing in the control range. An imaging process of shooting a subject and outputting a video signal;
A signal processing step for signal processing the video signal output from the imaging step;
A determination step of determining a shooting scene of the video signal output from the imaging step;
A computer program for causing a computer to execute a control step for controlling the signal processing step so as to perform signal processing on the video signal according to the shooting scene determined in the determination step,
The computer program according to claim 1, wherein a control range is provided for an image quality correction target value when image quality correction is performed on the video signal, and the signal processing step is controlled to perform signal processing in the control range.   A computer-readable storage medium storing the computer program according to claim 11.

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