JPH0767160B2 - Electronic still camera - Google Patents

Description

TECHNICAL FIELD The present invention relates to an electronic still camera, and more particularly to an improvement for capturing and recording a waveform displayed on the screen of an oscilloscope.

<Prior Art> Conventionally, the waveform on the screen of an oscilloscope is often photographed by an instant camera using a silver salt film.

On the other hand, recently, with the development of an electronic still camera, it is considered that the same waveform is photographed and recorded by the electronic still camera.

<Problems to be solved by the invention> However, while the sweep time of the oscilloscope can be variably set from an extremely short time to an extremely long time, and the waveform is not limited to a repetitive waveform, but may be a sudden single-shot waveform. Generally, the exposure time of an electronic still camera is not long, and for example, the practical exposure time of an electronic still camera that does not use a special cooling device for suppressing the dark current of the image pickup element is 1/2 second at the maximum.

Therefore, even if the waveform of the oscilloscope was recorded with the electronic still camera, it was difficult to match the timing, and only a part of the waveform could be recorded.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an electronic still camera capable of recording all desired waveforms displayed on the screen of an oscilloscope.

<Means for Solving the Problems> The electronic still camera according to the present invention is configured to variably set the exposure time and to sweep out unnecessary charges of the image pickup device at the time when an external trigger signal is input. It is characterized by comprising means for prohibiting reading during a set exposure time and means for reading out the image sensor after the set exposure time has elapsed.

<Operation> In the above configuration, when capturing a waveform, the exposure time is set to one sweep time of the oscilloscope or more, for example, 100 msec or more if the time axis is 10 graduations and 10 msec per graduation, and the trigger signal (synchronization signal from the oscilloscope is set. ) Is entered.
At this time, the unnecessary charges of the image sensor are first swept out so that the exposure is started at the same time as the input of the trigger signal, and thereafter the reading is prohibited for the set exposure time. It is accumulated in the image sensor as electric charges.
After the exposure time has elapsed, the image sensor is read out, and as a result, the exposure is started in agreement with the input of the trigger signal from the outside, so that there is no delay after the input of the trigger signal, The video signal is recorded in the recording device.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

Figure 1 uses a magnetic disk (video floppy),
An embodiment is shown in which a general electronic still camera for color with a program automatic exposure function is used as a base, and a function of recording a waveform on an oscilloscope screen is added to the base.

Therefore, the main CPU 1 for main control has a switch 3 for changing the mode between the normal photographing mode and the oscilloscope photographing mode.
Is connected and in oscilloscope shooting mode,
The control signal 5 allows the AE-CPU 7 for automatic exposure control to open the mechanical shutter 9 and manually operate the iris 10. Further, in the oscilloscope shooting mode, the control signal 11 switches the gamma of the video signal processing circuit 13 to the characteristic shown in FIG. 3 to improve the contrast and S / N of the video, and the control signal 15 controls the frequency for the chroma signal. The resolution of the black and white recording is improved by stopping the operation of the modulator 73 and widening the band of the luminance signal frequency modulator 67.

In order to realize the present invention, a dial type exposure time setting device 21 having a shutter speed scale is connected to the AE-CPU7,
− Set value signal 23 of exposure time to main CPU1 via CPU7
I am trying to enter. In addition, a terminal (EXT TRG) 27 for inputting a trigger signal 25 from the outside such as an oscilloscope.
Is connected to the main CPU1. 29 is a release button, which is connected to the main CPU1. A dial type aperture setting device 31 is connected to the AE-CPU 7. Maine
In the oscilloscope shooting mode, the CPU 1 inputs the trigger signal 25 from the input terminal 27 or the ON signal 33 of the release button 29 as shown in FIG. 2, and the read inhibit signal to the timing generator (TG) 35. 37 is output for the time TS set by the exposure time setting device 21, the read prohibition is released after the elapse of this time, and the recording trigger signal 41 is output to the recording gate 39.

The timing generator 35 drives an image sensor 45 such as an interline CCD via the driver 43, and normally,
The read pulse FS is repeatedly output in synchronization with the vertical sync signal VD. Main CP in oscilloscope shooting mode
When receiving the read inhibit signal 37 from U1, as shown in FIG. 2, an extra read pulse 36 is output at the rising edge of the signal 37 to sweep out unnecessary charges of the image sensor 45, and thereafter the read inhibit signal 37 is received. The read pulse is not output during the period TS, and the read pulse FS is output again after the elapse of this period. Anyway, the read signal 47 is the video signal processing circuit.
The color video signal 49 of the NTSC system and the signals 51, 53, 55 for magnetic recording are output to the input terminal 13.

The NTSC color video signal 49 is an electronic viewfinder.
It is output to the driver 59 of 57 and also output to the outside from the terminal 63 through the buffer amplifier 61. Of the signals for magnetic recording, 51 is a luminance signal (including a synchronization signal), which is input to the frequency modulator 67 through the pre-emphasis circuit 65. 53 is an RY signal and 55 is a BY signal, which are line-normalized by the circuit 69 and input to the frequency modulator 73 through the pre-emphasis circuit 71. The output signals 75 and 77 of the frequency modulators 67 and 73 are mixed by the mixer 79 and input to the recording amplifier 81.

Under the control of the servo circuit 85, the video floppy 83 operates at a constant speed by the motor 87, for example, 3600 rpm, and the vertical synchronizing signal VD generated by the timing generator 35 and the rotational phase of the video floppy 83 as shown in FIG. One PG pulse represented per one rotation rotates in a predetermined phase relationship. 89 is a motor driver, 91 is a frequency detector, 93 is a PG
The coil and 95 are PG pulse generation circuits.

When the recording gate 39 receives the recording trigger signal 41 from the main CPU 1, the next PG pulse and the next PG pulse are received as shown in FIG.
During the pulse, a recording command (REC) signal 97 is given to the recording amplifier 81 to cause the recording current 101 to flow through the magnetic head 99.

Note that 102 and 103 are optical systems such as lenses, and 105 is a shutter 9.
, 107 is a motor for driving the iris 10, and 109 is a phase modulator for data recording. The phase modulator 109 is supplied with data 111 such as the date of photographing from the main CPU 1 as necessary, and outputs a signal 113 modulated by DPSK or the like to the mixer 79.

Next, the operation in the oscilloscope shooting mode will be described.

(1) The electronic still camera is attached to the oscilloscope using a fixture (not shown), and the switch 3 is turned on to enter the oscilloscope shooting mode.

As a result, the shutter 9 is opened, the iris 10 can be manually operated, gamma has a high contrast characteristic, and a high resolution black and white recording mode is set.

(2) Next, operate the dial of the exposure time setting device 21 to set the exposure time of one sweep time of the oscilloscope or more.
Set TS. Also, while observing the electronic viewfinder 57, the dial of the aperture setting device 31 is operated to set the aperture value of the iris 10.

(3) Next, connect the trigger input terminal 27 to the trigger output terminal of the oscilloscope. In the case of a repetitive waveform, the release button 29 may be turned on.

When the trigger signal 25 or the ON signal 33 of the release button 29 is input to the main CPU 1, unnecessary charges of the image sensor 45 are swept out, and reading of the image sensor 45 is prohibited for the set exposure time TS. After the exposure time TS has elapsed, the read prohibition is released and the video signal read by the first read pulse 114 (see FIG. 2) is recorded in the video floppy 83. That is, the waveform of the oscilloscope is stored as a television signal, which can be reproduced when necessary and redisplayed on a television receiver or monitor.

In addition, connect the switch 115 to the main CPU1, and send the external trigger signal 25 only when the switch 115 is on.
The operability may be improved by incorporating it into 1.

Further, in the above-mentioned embodiment, since the general electronic still camera is used as a base, it has two functions of the normal photographing mode and the oscilloscope photographing mode, but it goes without saying that it may be a dedicated camera having only the oscilloscope photographing mode. Yes. Further, the aperture setting device 31 can adjust the brightness on the oscilloscope side, and is not always necessary. Further, although the reproducing function is not mentioned in the above embodiment, it is not always necessary because the reproducing function may be performed by another reproducing-only device or a recording / reproducing device. Of course, you can add a playback function to the camera itself. Furthermore, although the video signal is recorded on the magnetic disk in the above-mentioned embodiment, the recording medium is not limited, and the video signal is recorded on a semiconductor memory, for example, as an A / D signal.
It may be a digital electronic still camera that converts and records.

<Advantages of the Invention> According to the present invention, since the photographing timing always matches the trigger signal from the oscilloscope, it is possible to minimize the exposure time of the camera, and even in an electronic still camera in which the exposure time cannot be set long. , The waveform displayed on the oscilloscope screen can be photographed and recorded.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a timing chart for explaining the operation, and FIG. 3 is a diagram showing an example of gamma characteristics. In the drawing, 1 is a main CPU, 21 is an exposure time setting device, 25 is a trigger signal, 27 is an input terminal, 29 is a release button, 36 is a pulse for sweeping unnecessary charges, 37 is a read inhibit signal, and 45 is a read inhibit signal.
Is an image sensor, 51 is a luminance signal, 67 is a frequency modulator, 81 is a recording amplifier, 83 is a video floppy, 99 is a magnetic head, and TS.
Is the exposure time, and FS is the read pulse.

Claims (4)

[Claims] 1. An electronic still camera for recording a still image signal from an image pickup device in a recording device, wherein the exposure time is variably set, and the image pickup device of the image pickup device coincides with an input time of a trigger signal from the outside. An electronic still camera comprising: means for sweeping out unnecessary charges and forbidden reading for a set exposure time; and means for reading an image sensor after a set exposure time. 2. An electronic still camera according to claim 1, which has an external synchronous photographing mode and a normal photographing mode. 3. The electronic still camera according to claim 1, which has an oscilloscope shooting mode and a normal shooting mode. 4. The electronic still camera according to claim 3, further comprising a mechanical shutter and an electronic shutter, wherein the mechanical shutter is opened in an oscilloscope photographing mode to open and close the mechanical shutter in synchronization with an exposure time. The electronic still camera is characterized in that the camera is stopped and the photographing is performed only by the electronic shutter.