JP3613736B2 - Still video camera - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a still video camera that can be set to a video mode for outputting a video signal to a monitor.
[0002]
[Prior art]
Some still video cameras not only record images, but also have an image reproduction function, and can be viewed by connecting to a monitor, and others have a mode called a video mode.
[0003]
In video mode, an NTSC video signal is output to the monitor to display a moving image on the monitor in real time, and the desired image is recorded as a still image while viewing the image, and the recorded image is played back on the monitor. This mode is disclosed in Japanese Patent Laid-Open No. 1-307734 by the present applicant.
[0004]
[Problems to be solved by the invention]
If the video circuit for generating the video signal is always turned on to set the video mode, the video circuit consumes a battery because of the large power consumption. In addition, if a video mode selection switch is provided and the video circuit is turned on only when the video mode is selected, the number of switches increases, which is not only complicated, but also forces the user to change to the video mode. Become.
[0009]
[Means for Solving the Problems]
The above-described problem includes a connector that can be coupled to a cable that is connected to a monitor that reproduces an image. When the connector and the cable are coupled, the video signal is automatically switched to a video mode that is output to the monitor. Is solved.
[0014]
[Action]
A switch circuit for detecting that the camera-side jack for outputting a video signal is connected to a plug connected to a monitor for reproducing an image, and that the jack and the plug are connected in the recording mode. Is detected, the video circuit is automatically turned on to enable shooting, recording and reproduction in the video mode.
[0018]
【Example】
The present invention will be described in detail with reference to FIGS.
[0019]
FIG. 1 is a block diagram of a digital still camera according to an embodiment of the present invention, and FIG. 2 is a detailed view of a signal processing unit.
[0020]
First, each operation will be described. The image pickup device 3 is a CCD or the like, and subjects information formed on the image pickup device 3 by the optical photographing lens 1 is photoelectrically converted and output as an electric signal. The pre-process unit 4 performs basic analog processing before AD conversion such as pre-amplification having an AGC function and clamp and CDS. Further, the AGC reference gain for the pre-amplification can be changed under the control of the main microcomputer 10.
[0021]
The AD converter 5 converts the analog CCD output signal into digital data.
[0022]
The signal processing unit 6 performs processing such as filter processing, colorization processing, knee processing, and color conversion processing on the digitized CCD image data, and outputs the data to the memory controller 9 in, for example, YCrCb format. On the other hand, the signal processing unit 6 also includes a DA converter, and outputs the colorized video signal input from the AD conversion unit 5 and the image data input reversely from the memory controller 9 as analog signals. You can also. The function switching is performed by exchanging data with the main microcomputer 10, and exposure information, focus information, and white balance information of the CCD signal can be output to the main microcomputer 10 as necessary.
[0023]
The memory controller 9 stores the digital image data input from the signal processing unit 6 in the frame memory 11, and conversely outputs the image data in the frame memory 11 to the signal processing unit 6. The frame memory 11 is an image memory that can store image data of at least one screen. VRAM, SRAM, DRAM, etc. are generally used, but here, VRAM that can operate independently from the CPU bus is used. . Further, this memory may be shared with the system memory.
[0024]
The image storage memory 12 is a memory built in the main body, and is stored after an image photographed in the frame memory 11 is subjected to image compression processing or the like by the main microcomputer 10. As the built-in memory for storing images, there are SRAM, DRAM, EEPROM, and the like, but EEPROM is preferable in view of storing image data in the memory.
[0025]
The PC card controller 13 (PCMCIA controller) connects an external recording medium such as an IC memory card and the main microcomputer 10, and after an image shot in the frame memory is subjected to image compression processing by the main microcomputer 10. The data can be recorded on an external recording medium via the PC card controller 13. As an external storage IC memory card connected via the PC card controller 13, an SRAM card, DRAM card, EEPROM card, or the like can be used, and image data is directly transmitted via a public line using a modem card or ISDN card. May be transferred to a remote recording medium.
[0026]
The strobe unit 15 is a circuit for causing the built-in strobe to emit light, and here, the light emission timing is obtained by the main microcomputer 10 that controls the photographing sequence.
[0027]
The serial port driver 16 performs signal conversion for information transmission between the camera body and an external device. As a serial transmission means, there are recommended standards known by names such as RS-232-C and RS-422-A, but here, RS-232-C is used.
[0028]
The sub-microcomputer 17 controls the man-machine interface such as an operation switch of the camera body and a liquid crystal display, and transmits information to the main microcomputer 10 as necessary. Here, a serial input / output terminal is used for information transmission with the main microcomputer 10. In addition, it controls the auto date 19 that has a clock function and records the date and time of photographing together with the image.
[0029]
The aperture drive unit 20 is configured by, for example, an auto iris or the like, and changes the optical aperture 2 under the control of the main microcomputer 10.
[0030]
The focus drive unit 21 is configured by, for example, a stepping motor, and is for changing the position of the lens 1 under the control of the main microcomputer 10 and appropriately aligning the optical focus surface of the subject with the image sensor 3.
[0031]
The main microcomputer 10 mainly controls shooting, recording, and playback sequences, and further performs compression playback of shot images and serial port transmission with external devices as necessary. Here, as image compression, the JPEG system or the JBIG system standardized by CCITT and ISO is used. Although the main microcomputer 10 performs this calculation here, depending on the capability of the main microcomputer 10, a compression / decompression-dedicated IC may be arranged on the CPU bus.
[0032]
Next, a series of basic operations from shooting to memory recording will be described.
[0033]
The operation mode of the camera is set from various switch information connected to the sub-microcomputer 17, and information for photographing is output to the main microcomputer 10 as serial information. In accordance with this information, the main microcomputer 10 sets the memory controller 9, the signal processing unit 6, the preprocessing unit 4, and the PC card controller 13 and the serial port driver 16 as necessary.
[0034]
When the release switch S1 of the sub microcomputer 17 is pressed, the sub microcomputer 17 transmits the information to the main microcomputer 10. When the main microcomputer 10 knows that the S1 signal has become active, it issues an image input command to the signal processing unit 6, and the signal processing unit 6 operates the image sensor 3, the preprocessing unit 4, and the AD conversion unit 5. Receive a CCD image. After the received CCD image data is subjected to basic signal processing by the signal processing unit 6, focus information is created from the high frequency component of the luminance data and exposure data is created from the low frequency component. The main microcomputer 10 reads these data from the signal processing unit 6 and performs gain control of the AGC amplifier of the aperture driving unit 20 and the focus driving unit 21 and further the preprocessing unit 4 as necessary to obtain an appropriate exposure and focus. Converge until is obtained. Also, depending on the operation mode, an analog image signal is output from the signal processing unit 6 and output to an external monitor as an NTSC signal.
[0035]
When the signal indicating that the release switch S2 has been pressed is input from the sub microcomputer 17 to the main microcomputer 10 after the exposure value and focus are converged to appropriate values, the main microcomputer 10 instructs the memory controller 9 to take in the instruction. Output. If necessary, a light emission signal is output to the flash unit 15 at the field timing of the captured image. When the image capture command is received by the memory controller 9, the synchronization signal from the signal processing unit 6 is detected, and image data in the YCrCb format or the like output from the signal processing unit 6 is captured in the frame memory 11 at a predetermined timing. When the frame memory 11 finishes capturing the image, the memory controller 9 displays a status indicating that the capture is complete, and the main microcomputer 10 reads this to know that the main microcomputer 10 has finished shooting.
[0036]
After shooting is completed, the main microcomputer 10 compresses the image as necessary, and transfers the image data to the image storage memory 12, the externally connected GPS card 14, or the personal computer connected to the external serial port. .
[0037]
In the reproduction display operation, the main microcomputer 10 reads the image data from the image storage memory 12, an externally connected PC card, or a personal computer connected to the external serial port, and decompresses the image as necessary. Write to the memory 11. Thereafter, when a command for displaying an image is issued to the signal processing unit 6 and the memory controller 9, the memory controller 9 reads the image data from the frame memory 11, and passes through the video processing unit 7 through the signal processing unit 6 and the NTSC output terminal. The image analog signal is output to the connector 8.
[0038]
In this way, the camera's shooting, recording, playback, display, and transmission functions are achieved.
Next, an embodiment of a digital still camera according to the present invention will be shown.
[0039]
In FIG. 1, reference numeral 8 denotes a connector for outputting an NTSC video signal that can be coupled to a cable connected to a monitor for reproducing an image. FIG. 3 shows a part of the connector. FIG. 3 is a diagram in which the camera-side jack 80 and the cable-side plug 90 are coupled. The plug-shaped positive electrode portion 91 of the plug 90 becomes conductive when inserted into the hole-shaped positive electrode portion 81 of the jack 80. When the tubular negative electrode portion 92 is inserted into the tubular negative electrode portion 82 of the jack 80, electrical connection is established. Reference numerals 83 and 93 denote insulating portions. A changeover switch 85 is built in the jack 80, and the switch 85 is turned ON / OFF depending on whether or not the contact piece 85a is pressed by the positive electrode portion 91 of the plug 90.
[0040]
When the plug 90 is removed from the jack 80, the normal mode is selected and normal recording or reproduction is performed. If the insertion / removal detection circuit (not shown) detects that the plug 90 is inserted into the jack 80 during the recording mode, information is output from the sub-microcomputer 17 to the main microcomputer 10 as a video mode, Set up each process. Then, shooting, recording, and playback in the video mode are enabled. When the plug 90 is removed from the jack 80, the video mode is automatically terminated and the normal recording mode is entered.
[0041]
The switch 85 may be built in the plug, and the plug may be connected to the camera side and the jack may be connected to the cable side.
[0042]
FIG. 4 is a flowchart of AGC gain control when shooting and recording is performed using a strobe after a video mode is selected and a through video signal is output. When the video mode is selected and the through video signal is output, if the luminance of the subject is low, the main microcomputer 10 increases the AGC gain and waits for the second-stage release switch S2 to be pressed. When a signal indicating that the release switch S2 has been pressed is input and it is detected that flash photography is being performed, the main microcomputer unit restores the AGC gain and outputs a light emission signal to the flash unit 15 at the field timing of the captured image. , Capture images.
[0043]
FIG. 5 is a flowchart of AWB control when shooting and recording is performed using a strobe after a video mode is selected and a through video signal is output. When the video mode is selected and the through video signal is output, the RGB gain of the signal processing unit 6 is controlled so that the WB value matches the color temperature of the subject, AWB is performed, and the release switch S2 is pressed. wait. When a signal indicating that the release switch S2 has been pressed is input and it is detected that the flash is being shot, the flash WB value is changed to match the color temperature of the flash, and the flash unit 15 emits light at the field timing of the captured image. Output signal and capture image.
[0044]
FIG. 6 is a flowchart for selecting AWB. It is determined whether the mode is the normal shooting mode or the video mode, and the continuous AWB or the simple AWB is performed accordingly.
[0045]
FIG. 7 is a flowchart of the continuous AWB. WB calculation is performed using AWB data swept out from the DSP or AWB data obtained by other methods. AWB is performed by continuously changing the RGB gain until an appropriate WB is obtained.
[0046]
On the other hand, the simplified AWB flowchart shown in FIG. 8 prepares some RGB gain control data, changes the control data one after another, and obtains WB values in several states. Next, the WB values are compared, and as a result, AWB is performed by controlling with the RGB gain data when the most appropriate WB is obtained.
[0047]
FIG. 9 is a timing chart of the continuous AWB control, and FIG. 10 is a timing chart of the simple AWB control. If the setting data is changed a times before the proper WB is obtained in the continuous AWB control, the time required for (a + 1) × 2 fields is required, whereas in the simple AWB, b control data is prepared , (B + 1) field time.
[0048]
This applies not only to AWB but also to AE, and AE is performed using the AE data generated in the AE signal creation unit. However, in the case of through, control is performed to continuously change the aperture and shutter speed. In the normal AE mode, several aperture and shutter speed control data are set and changed one after another, and the mode is switched to simple AE that is controlled with the most suitable exposure data in each state. AE suitable for each can be performed.
[0049]
The above system is merely an example, and all processing may be performed by software. In this system, operations such as AE and AWB are performed by software. However, these operations may be performed by hardware.
[0050]
Further, in the video mode, it is possible not to record an arbitrarily shot image by providing a recording unnecessary mode. In the normal video mode, an image is taken and subsequently played back. The image taken at this time is compressed and recorded in a memory card or an image storage memory. Here, in the recording unnecessary mode, the digital image data is accumulated in the frame memory and is reproduced without being recorded in the memory card or the image accumulation memory. As a result, shooting and playback in the video mode can be enjoyed without worrying about the remaining capacity of the memory card or image storage memory.
[0051]
Furthermore, in the video mode, the captured data is compressed and recorded in the memory card or the image storage memory. When the data becomes full, the recording mode is automatically entered, and the memory card or the image storage memory is stored. It is also possible to take and play back images without recording them in the memory.
[0052]
Furthermore, although the above embodiments have been described with respect to a digital still camera, the present invention can also be applied to a normal still video camera for recording on a floppy disk.
[0053]
【The invention's effect】
According to any one of claims 1 to 3, in the still video camera having the video mode, the video circuit is turned on only in the recording mode in which the connector is inserted, by detecting the insertion / removal of the connector. By reducing the power consumption of the camera. Further, by reducing the number of switches, the switches can be simplified, and the camera has excellent operability.
[Brief description of the drawings]
FIG. 1 is a block diagram of a digital still camera.
FIG. 2 is a detailed diagram of a signal processing unit.
FIG. 3 is a diagram in which a camera-side jack and a cable-side plug are combined.
FIG. 4 is a flowchart of AGC gain control when shooting and recording is performed using a strobe after a video mode is selected and a through video signal is output.
FIG. 5 is a flowchart of AWB control when shooting and recording is performed using a strobe after a video mode is selected and a through video signal is output.
FIG. 6 is a flowchart for selecting an AWB.
FIG. 7 is a flowchart of continuous AWB.
FIG. 8 is a flowchart of simplified AWB.
FIG. 9 is a timing chart of continuous AWB control.
FIG. 10 is a timing chart of simplified AWB control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lens 3 Image pick-up element 4 Preprocessing part 6 Signal processing part 8 Connector 9 Memory controller 10 Main microcomputer 11 Frame memory 12 Image storage memory 13 PC card controller 15 Strobe part 80 Jack 90 Plug

Claims (3)

A connector that can be coupled to a cable that connects to a monitor that reproduces an image, and when the connector and the cable are coupled, a video signal is automatically switched to a video mode that is output to the monitor. Still video camera. The still video camera according to claim 1, wherein the cable includes a plug or a connector, and a connector or a plug coupled to the plug or the connector. The still video camera according to claim 2, further comprising a switch that is switched when the cable is connected to the connector or the plug.

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