JPH0365625A - High-speed image pickup apparatus - Google Patents

Abstract

PURPOSE:To enable deliberate observation of a repeated high-speed emission phenomenon from the beginning to the end by increasing a delay time sequentially for each frame of a video camera and by outputting a gate trigger signal to a gate power source. CONSTITUTION:An apparatus comprises a gate image intensifier 10 conducting a shutter operation at a high speed, a CCD camera 12 converting an output signal of the gate image intensifier 10 into a video signal, a gate power source 14 controlling the gate image intensifier 10 by a gate trigger signal, and an image sampling device 16 increasing a delay time sequentially for each frame of the CCD camera 12 and outputting the gate trigger signal to the gate power source 14. Since the delay time is increased sequentially for each frame of the CCD camera 12 and a control signal is sent from the gate power source 14 to the image intensifier 10, a high-speed emission phenomenon which ends in several hundred nanoseconds to several microseconds can be picked up and observed deliberately for several seconds to several minutes or several hours.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a high-speed imaging device, and more particularly to a high-speed imaging device capable of capturing repeated high-speed light emission phenomena as slow images.

[Conventional technology]

For example, conventional equipment for photographing repeated light emission phenomena excited by a laser uses a gate image intensifier (hereinafter referred to as gate II) and a COD camera, and a maximum shutter speed of 3 nSec is used to capture high-speed light emission phenomena.
There are high-speed shutter cameras that capture the moment.

[Problem to be solved by the invention]

The above-mentioned conventional high-speed shutter camera has one of the repeated flashing phenomena.
It only captures an image at one timing, for example, at the rising edge, and unless you change the timing, it will always be displayed on the TV monitor as a still image.
There was a problem in that it was not possible to observe the beginning or end of the high-speed light emission phenomenon. The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a high-speed imaging device that allows repeated high-speed light emission phenomena to be observed slowly from beginning to end. .

[Means to solve the problem]

The present invention provides a gated image intensifier that performs a shutter operation at high speed, a video camera that converts an output signal of the gated image intensifier into a video signal, and a gate that controls the gated image intensifier using a gate trigger signal. The above object is achieved by a high-speed imaging device comprising a power source and an image sampling device that sequentially increases the delay time for each frame of the video camera and outputs a gate trigger signal to the gate power source. be. Further, the present invention provides the image sampling device with the following equation: (Tf-T)/where Tf is the one frame period of the video camera, T is the maximum value of the delay time, and Tt is the trigger pulse period of the gate trigger signal. The above object is achieved by providing a trigger pulse number calculation and limiting circuit which calculates Tt -1 and sets this as the number n of trigger pulses output within one frame.

[Effect]

In this invention, the delay time is increased sequentially for each frame of the video camera and a control signal is sent from the gate power supply to the image intensifier, so that
The high-speed light emission phenomenon, which ends in several m5ec, is imaged slowly over a period of several seconds to several minutes or hours, and t12
can be measured.

【Example】

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this embodiment includes a gate image intensifier (hereinafter referred to as gate II) 10 that performs a high-speed shutter operation, and a CCD camera 12 that converts the output signal of this gate Ill0 into a video signal. , a gate power supply 14 that controls the gate lll0 by a gate trigger signal, and a vertical synchronization signal of the CCD camera 12;
and an image sampling device 16 that sequentially increases the delay time for each frame of the CCD camera 12 based on the light emission timing signal of the repeated light emission phenomenon, and outputs a gate trigger signal to the gate power supply 14. 18. Reference numeral 20 in FIG. 1 is a photodetector for capturing the light emission timing of the repeated light emission phenomenon and outputting the light emission timing signal to the image sampling device 16; 22 is a television monitor for monitoring the video signal from the CCD camera 12; 2
4 designates video decks for recording video signals. Next, referring to FIG. 2, the image sampling device 16
Explain the circuit. This circuit includes a CPU, and a Tf measurement circuit 2 that measures one frame period Tf of the CCD camera 12 based on a frame signal (vertical synchronization signal) Sf from the CCD camera 12.
6, and a Tt measurement circuit 28 that measures the trigger pulse period Tt based on the light emission timing signal St from the photodetector 20.
, a delay circuit 30 that outputs a pulse signal delayed by a predetermined time with respect to the light emission timing signal St, and the Tf
From the signal Tf from the measurement circuit 26, the signal Tt from the Tt measurement circuit 28, and the maximum delay time T which is a setting parameter, the trigger pulse number limit value n per frame is determined.
= (Tf-T)/Tt-1, and the signal from the delay circuit 30 is limited based on the signal of the limit trigger pulse number n from the trigger pulse number calculation circuit 32. Trigger pulse number limiting circuit 3
4, the maximum delay time T, and the delay time ΔT for each frame, a T/ΔT calculation circuit 36 that calculates the number of frames N=T/ΔT until all of the light emission phenomenon is photographed.
and the number of frames is T/Δ from the frame signal Sf.
The frame counter 38 stops and initializes the delay circuit 36 when it reaches N determined by the T calculation circuit 36, and at the same time outputs a stop signal to complete the process. The gate @ setting circuit 40 sets a gate width to the output signal and outputs it as a final gate trigger signal. As shown in FIG. 2, the delay circuit 30 sequentially changes the delay time ΔT, 2ΔT, 3ΔT, 4ΔT, etc. for each frame signal from the first light emission timing signal St.
The gate trigger signal is outputted to the gate power supply 14 by switching so as to increase the gate trigger signal. Next, the operation of the apparatus of the above embodiment will be explained. First, the frame signal Sf and the light emission timing signal St are C
The data is input from the CD camera 12 and the photodetector 20 to the image sampling device 16, respectively. These signals Sf and St are input to a Tf measurement circuit 26 and a Tt measurement circuit 28, respectively, where one frame period Tf and trigger pulse period Tt are determined. . The determined Tf and Tt are input to the trigger pulse calculation circuit 32. The trigger pulse calculation circuit 32 calculates the minimum number of gates per frame taking the maximum delay time T into consideration from the maximum delay time T (equal to one light emission time) which is a setting parameter and these signals Tf and Tt. n = (Tf-T
)/Tt-1 and outputs n to the trigger pulse limiting circuit 34. The reason why the number of gates n for each frame must be determined in the above manner will be explained. As shown in FIG. 4, the cycle Tf of the frame signal Sf from the CCD camera 12 and the cycle Tt of the light emission timing signal St are asynchronous. ΔT, 2ΔT, 3ΔT based on the light emission timing signal St for each frame according to the timing of the frame signal Sf.
The delay circuit 30 generates signals that are sequentially delayed. However, as mentioned above, since Tf and Tt are asynchronous, the number of images stored in one frame is different, as shown in FIG. 4, for example. In the case of Fig. 4, when the delay time ΔT is 6 sheets, 2 sheets
When ΔT, there are 7 pieces. Therefore, the number of trigger pulses per frame must be calculated by determining Tf and Tt in advance, and control must be performed according to the smaller number. As described above, the trigger pulse number calculation circuit 32 calculates the number n to match this small number of times. The control signal from the delay circuit 30 is limited by the trigger pulse number limiting circuit 34 so as to output signals up to the input trigger pulse number n. Further, the gate width setting circuit 40 sets the gate @ (shutter speed time) using a gate width to signal, which is a setting parameter, and outputs it to the gate power supply 14 as a gate trigger signal. Gate lll0 is gated at given timing and shutter speed based on a gate trigger signal input to gate power supply 14. On the other hand, N calculated by the T/ΔT calculation circuit 36 based on the set maximum delay time T and the delay time ΔT for each frame is input to the frame counter 38, and the frame counter 38 counts based on the frame signal Sf. When the number of frames has reached N, the delay circuit 30 is stopped and initialized, and a stop signal is output to terminate everything. Therefore, the video signal input to the television monitor 22 and video deck 24 captures the high-speed repetitive light emission phenomenon as a very slow video. At the same time, since the same image can be stored multiple times (n times) in one frame of the CCD camera 12, the S/
N can be improved. For example, considering the phenomenon in which light emission ends in 11 Sec, Δ
If T = 10 on sec is set, it corresponds to the frame interval time Tf = 100n Sec, so the time is extended by 30x10-3/100xlO-9 = 3x105 times, and the The light emission phenomenon can be imaged as a 300 second phenomenon. Note that in the above embodiment, the image sampling device 21
6 is composed of a Tf measuring circuit 26, a Tt measuring circuit 28, a delay circuit 30, a trigger pulse number calculating circuit 32, a trigger pulse number limiting circuit 34, a T/ΔT calculating circuit 36, a frame counter 38, etc. However, this is not limited to the embodiment, and other alternatives may be used as long as the image sampling device can substantially synchronize the asynchronous frame signal Sf and light emission timing signal St and control the delay circuit. Also, although the above embodiment uses a COD camera 12, it may be a video camera.

【Effect of the invention】

Since the present invention is configured as described above, it has the excellent effect that a fast m-slow luminescence phenomenon can be freely extended in time and captured as a slow luminescence phenomenon.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a high-speed imaging device according to the present invention, FIG. 2 is a circuit diagram showing a circuit of an image sampling device in the same embodiment, and FIG. 3 is an operation of a delay circuit in the same embodiment. FIG. 4, which is a block diagram showing the principle, is a timing chart of each signal in the image sampling device in the same embodiment. 2...CCD camera, 14...gate power supply, 6
... Image sampling device, 8... High-speed imaging device, 20... Photodetector, 2...
・TV monitor, 24...Video deck, 6...
Tf measurement circuit, 28...Tt measurement circuit, O...delay circuit, 2...Trigger pulse number calculation circuit, 4...Trigger pulse number limit circuit, 6...T/ΔT calculation circuit, 8 ...Frame counter 0...Gate width setting circuit.

Claims (2)

[Claims] (1) A gated image intensifier that performs a high-speed shutter operation, a video camera that converts the output signal of this gated image intensifier into a video signal, and a gate power supply that controls the gated image intensifier using a gate trigger signal. and an image sampling device that sequentially increases the delay time for each frame of the video camera and outputs a gate trigger signal to the gate power supply. (2) In claim 1, the image sampling device is configured such that (Tf− T)/Tt-
1. A high-speed imaging device comprising a trigger pulse number calculation and restriction circuit that calculates n and sets the number n of trigger pulses to be output within one frame.