JP2006345255A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of executing the control of compression processing based on a set compression ratio and the control of a suitable photographing function. <P>SOLUTION: The imaging apparatus is provided with a camera part and a camera signal processing part for performing photographing operation and outputting an image signal, a compression processing part for compressing and encoding the outputted image signal, a camera control part for controlling photographing operation, and a system control part for controlling the compression operation; where the system control part sets the compression ratio of the compression processing part and controls compression operation and the camera control part controls the operation speed of a prescribed photographing function in accordance with the set compression ratio. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus having a configuration for performing imaging to generate imaging data and compressing and encoding the generated imaging data.

  Encoding methods such as MPEG (Moving Picture Experts Group) 1, 2, and 4 have been established as techniques for highly efficient encoding of moving images. MPEG is based on discrete cosine transform (DCT), adaptive quantization, and variable length coding, and includes interframe (or field) predictive coding with motion compensation based on frame (or field) correlation, intraframe predictive coding, Is an encoding method combining the above.

  A camera-integrated recording apparatus (video camera) that employs MPEG as a compression encoding method for imaged data has already been commercialized. This video camera converts an optical image of a subject incident through a photographing lens into an imaging signal by a sensor such as a CCD, and further performs necessary camera signal processing and MPEG compression coding processing on the imaging signal to obtain a recording medium. Record the compressed image data.

Further, as a prior art related to the above video camera, for example, an imaging apparatus that sets a target information amount in MPEG processing in accordance with the content and nature of a moving image to be shot has been proposed (for example, Patent Document 1). reference.).
JP 2002-369142 A

  However, conventional video cameras are not configured to perform coordinated control between camera signal processing and compressed signal processing, and control is performed so that optimum results are obtained independently of each other. In addition, the configuration of Patent Document 1 described above controls the target information amount at the time of compression in accordance with the content of shooting. However, since the image quality is changed as a result, the degradation of the image quality is caused to the viewer during reproduction. There is a concern that it may cause an uncomfortable feeling or block noise. That is, there is a possibility that the photographed image is recorded with an image quality not intended by the photographer.

  The present invention has been made in view of the problems as described above. For example, the operation of the camera system, camera signal processing, and compression processing can be controlled according to compression control information such as setting of a compression rate based on a user instruction or the like. An object is to provide a certain imaging device.

  Another object of the present invention is to perform exposure and white balance operation control suitable for performing a compression process in which the compression rate can be arbitrarily set in the imaging apparatus.

  In order to solve the above problems, an imaging apparatus according to the present invention includes an imaging unit that performs a shooting operation and outputs an image signal, a compression processing unit that compresses and encodes an image signal output from the imaging unit, and An imaging control unit that controls a shooting operation in the imaging unit, and a system control unit that controls the compression operation in the compression processing unit, the system control unit sets a compression rate for the compression processing unit and controls the compression operation The imaging control unit controls the operation speed of a predetermined imaging function in the imaging unit in accordance with a compression rate set by the system control unit.

  According to the present invention, since the compression operation and the photographing function are controlled according to the compression rate, the photographed image can be recorded with the image quality intended by the photographer and suitable for the subsequent compression process. Shooting can be performed according to the operation content.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a configuration of an imaging apparatus according to an embodiment of the present invention.

  The operation of each unit when the imaging apparatus of FIG. 1 performs a shooting operation will be described. Reference numeral 101 denotes a photographing lens. A diaphragm 102 for adjusting the amount of light is disposed behind the photographing lens 101. The light that has passed through the photographing lens 101 and the diaphragm 102 is imaged as a subject image on the imaging surface of the image sensor 103. The image sensor 103 is a CCD (or CMOS) sensor, converts a subject image into an electric signal, and outputs the obtained image signal. The image sensor 103 is driven at a predetermined shutter speed according to the timing indicated by the CCD drive unit 114.

  Reference numeral 104 denotes a correlated double sampling (CDS) circuit for reducing accumulated charge noise included in the imaging signal output from the imaging element 103 and an automatic gain control (AGC) circuit for keeping the level of the imaging signal constant. CDS / AGC part including Reference numeral 105 denotes an A / D conversion unit that converts an imaging signal into a digital signal. The imaging signal output from the imaging element 103 is processed by the CDS / AGC unit 104, converted into a digital signal by the A / D conversion unit 105, and input to the camera signal processing unit 106.

  The camera signal processing unit 106 performs color interpolation processing, γ correction, white balance adjustment, and the like on the input digital signal. Further, the compression processing unit 107 performs a compression process on the digital signal processed by the camera signal processing unit 106 using a predetermined moving image compression encoding method. Here, the predetermined moving image compression encoding method is MPEG2 or H.264. H.264 / MPEG4-AVC. The digital video signal compressed by the compression processing unit 107 is recorded on the recording medium 115. The recording medium 115 can use a magnetic tape, a hard disk, an optical disk, or the like.

  Reference numeral 108 denotes a system control unit. The system control unit 108 includes a microcomputer for controlling each unit of the imaging apparatus. The system control unit 108 controls the compression processing in the compression processing unit 107. In addition, the system control unit 108 includes a camera (shooting) control unit 109 that controls the operation of each unit of the camera system and the control of camera signal processing as part of its function. Furthermore, the camera control unit 109 includes an AWB control unit 110 that is responsible for white balance control and an AE control unit 111 that is responsible for exposure control.

  The AWB control unit 110 controls the camera signal processing unit 106 to adjust the white balance of the captured image. Specifically, the AWB control unit 110 obtains the color temperature information of the subject from R (red), G (green), B (blue) components in the image signal, a color temperature sensor (not shown), and the like, and shoots based on the information. A white balance control signal for adjusting the white balance of the image is output to the camera signal processing unit 106. The AE control unit 111 controls the operation of the diaphragm 102 through the diaphragm control unit 113, and controls the shutter speed of the image sensor 103 through the CCD driving unit 114. Further, the AE control unit 111 controls the gain of the CDS / AGC unit 104, controls the camera signal processing unit 106, and adjusts the exposure level of the imaging signal to be appropriate.

  Reference numeral 112 denotes a compression rate changing operation unit for the user to instruct setting of a desired compression rate. The compression rate changing operation unit 112 uses a menu-type user interface. Based on the setting instruction input from the compression rate changing operation unit 112, the system control unit 108 transmits compression control information such as an appropriate quantization parameter to the compression processing unit 107. The compression processing unit 107 performs compression processing based on the compression control information. Further, the camera control unit 109 refers to the compression control information based on the setting instruction input from the compression rate changing operation unit 112, and controls each part of the camera system suitable for the set compression rate and control of camera signal processing. I do. When an instruction to change the compression ratio is given from the compression ratio change operation unit 112, control is performed to change the control of each part of the camera system and the control content of the camera signal processing.

  Next, the control operation of the system control unit 108 included in the imaging apparatus of the present embodiment will be described with reference to the block diagram of FIG. 1 and the flowchart of FIG.

  When the mode is changed to the mode for performing the photographing operation, the system control unit 108 causes the compression processing unit 107 to perform initialization such as setting of the compression rate (step S101). The initialization in step S101 is set by whether the compression processing unit 107 operates with a high compression rate setting or a low compression rate setting, or by giving necessary parameters or the like (compression control information) from the system control unit 108. It is an operation to do. At this time, the low compression ratio may be set by default at the time of start-up, or a setting that inherits the compression ratio that has been valid during the previous operation may be used.

  Furthermore, the system control unit 108 transmits to the camera control unit 109 compression control information related to the compression rate setting initialized by the compression processing unit 107 in step S101. Then, the camera control unit 109 controls the operation of each part of the camera system via the AWB control unit 110 and the AE control unit 111, and controls the AE and AWB control operations (control speed) according to the transmitted compression control information. Initialization is performed (step S102). By the initialization in step S102, the setting is made such that the AE and AWB operations are performed at high speed (normal control speed) when the low compression is set, and the AE and AWB operations are performed at a lower speed than when setting the low compression when the high compression is set. Settings are made. The reason for controlling the AE and AWB operations at a low speed when high compression is set is, for example, rather than operating the camera system at a high speed when the shooting scene suddenly changes or when the AE / AWB control fluctuates. This is because operating at a low speed can reduce damage (such as occurrence of block noise) that occurs when compression is performed at a high compression rate in the subsequent compression process. The state where the AE and AWB operations are controlled at low speeds means that the feedback gain of the video signal correction data in AE and AWB control is lower than the normal (high speed) state, and the feedback update cycle is longer than the normal (high speed) state. State.

  In this way, the digital signal generated by shooting can be compressed and recorded on the recording medium 115 according to the set compression rate. If the compression rate is not changed from this state (NO in step S103), the photographing operation is performed with the current setting, and the process proceeds to step S107. If the user operates the compression rate change operation unit 112 and gives an instruction to change the compression rate (YES in step S103), if the changed state is compression priority (YES in step S104), step S105a When the compression priority is not given (that is, when the image quality priority is given) (NO in step S104), the process moves to step S105b. The compression priority in step S104 is an instruction to set a high compression ratio. In general, the higher the compression rate, the worse the image quality after compression, but it is useful because the time that can be recorded on the recording medium 115 becomes longer. This is also called recording time priority setting. On the other hand, when compression priority is not given in step S104, an instruction to set a low compression ratio is given. By performing compression processing at a low compression rate, image quality deterioration after the compression processing can be reduced.

  When the system control unit 108 receives a compression priority instruction and sets a high compression ratio, the system control unit 108 controls the AE and AWB control operations (control speed) at a low speed via the camera control unit 109 in the same manner as the initialization operation described above. The mode is switched to the operating mode, and shooting control is performed in the subsequent shooting operation (step S105a). When the system control unit 108 receives the image quality priority instruction and performs the low compression ratio setting, the system control unit 108 performs the AE and AWB control operations (control speed) via the camera control unit 109 in the same manner as the initialization operation described above. The mode is switched to the mode for operating at high speed, and the imaging control in the subsequent imaging operation is performed (step S105b).

  In addition, the system control unit 108 gives the compression control information based on the changed compression rate to the compression processing unit 107, and performs compression processing according to the newly set compression rate (step S106).

  When the control speed of the AE and AWB is changed in step S105a or S105b and the compression process can be executed at the compression rate changed in step S106, the digital signal generated by the shooting is continuously changed according to the changed compression rate. Thus, the data can be compressed and recorded on the recording medium 115.

  The control operation of the system control unit 108 is continued until the photographing is finished (step S107). When the photographing is not finished, step S103 and subsequent steps can be executed, and when the photographing is finished, this flow is finished.

  Further, regarding the high compression rate setting described above, such a high compression shooting mode is extremely low, for example, when the camera is remotely operated using a low bit rate line, or when a video is transmitted from a portable terminal with a built-in camera. It is also useful when a communication path using a bit rate radio path is used.

It is the block diagram which showed the structure of the imaging device of this embodiment. It is the flowchart which showed the control operation of the system control part contained in the imaging device of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Shooting lens 102 Diaphragm 103 Image pick-up element 104 CDS / AGC part 105 A / D conversion part 106 Camera signal processing part 107 Compression processing part 108 System control part 109 Camera control part 110 AWB (white balance) control part 111 AE (exposure) control Unit 112 compression ratio changing operation unit 113 aperture control unit 114 CCD driving unit 115 recording medium

Claims (8)

An imaging means for performing an imaging operation and outputting an image signal;
Compression processing means for compressing and encoding an image signal output from the imaging means;
Shooting control means for controlling the shooting operation in the imaging means;
System control means for controlling the compression operation in the compression processing means,
The system control means controls the compression operation by setting a compression rate for the compression processing means, and the imaging control means sets the operation speed of a predetermined imaging function in the imaging means to the compression rate set by the system control means. An imaging device that is controlled in response.   The predetermined photographing function is an exposure adjustment function, and the photographing control unit controls an operation speed of the exposure adjustment function in accordance with a compression rate set by the system control unit. The imaging device described in 1.   The predetermined photographing function is a white balance adjustment function, and the photographing control unit controls an operation speed of the white balance adjustment function in accordance with a compression rate set by the system control unit. Item 2. The imaging device according to Item 1.   The predetermined photographing function is an exposure adjustment function and a white balance adjustment function, and the photographing control means sets the operation speed of the exposure adjustment function and the white balance adjustment function according to the compression rate set by the system control means. The imaging apparatus according to claim 1, wherein the imaging apparatus is controlled.   When the system control unit sets the compression processing unit to perform compression processing at a high compression rate, the imaging control unit controls the exposure adjustment function of the imaging unit to operate at a lower speed than usual. The imaging device according to claim 2, wherein:   When the system control unit sets the compression processing unit to perform compression processing at a high compression rate, the shooting control unit controls the white balance adjustment function of the imaging unit to operate at a lower speed than usual. The imaging apparatus according to claim 3 or 4, wherein   If the system control unit changes the setting so that the compression processing unit performs a compression process with a higher compression rate during the imaging operation of the imaging unit, the imaging control unit performs the exposure adjustment in the imaging unit. The imaging apparatus according to claim 2, wherein the operation speed of the function is changed so as to operate at a lower speed than before.   When the imaging control unit changes the setting so that the system control unit performs a compression process with a higher compression rate on the compression processing unit while the imaging unit is performing a shooting operation, the shooting control unit performs the white balance in the imaging unit. The imaging apparatus according to claim 3 or 4, wherein the operation speed of the adjustment function is changed so as to operate at a lower speed than before.

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