JP2005354209A - High-speed photographing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed photographing system capable of assuring the exposure amount required for photographing without affecting a subject, at a relatively low cost. <P>SOLUTION: The photographing system comprises a high-speed video camcorder 13 capable of outputting signals synchronous with photographing, and a light source 14 that uses an LED which can be turned ON/OFF by the synchronous signal. The light source 14 may be the one with an LED that can be turned ON/OFF in synchronous with exposure timing of each photography frame. The LED is relatively low cost, and has less infrared component as compared with a halogen lamp or metal-halide lamp, causing less calorific value at a photographing object with the same amount of irradiation of light. Since LED has good response to an input, it is turned ON/OFF while well following high-speed photographing such as one million frames/second, thereby reducing calorific value of the photographing object as well. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a high-speed video camera used for shooting high-speed phenomena such as destruction, explosion, and combustion, and a system including illumination therefor.

For example, high-speed imaging devices (high-speed video cameras) for continuously capturing high-speed phenomena such as explosion, destruction, combustion, collision, and discharge for a short time have been developed (for example, Non-Patent Documents 1 and 2). ). Such a high-speed photographing apparatus can perform photographing at a very high speed of about 1 million images / second at the maximum.
“Developed a super-high-speed video camera with a shooting speed of 1 million frames / second (press release dated September 27, 2001)” [online], Shimadzu Corporation, [searched June 2, 2003], Internet, < URL: http://www.shimadzu.co.jp/news/press/010927.html> Hiromasa Maruno, Yasushi Kondo, Takeharu Eto, “High-speed video camera using pixel peripheral recording image sensor”, Applied Optics 2002 Vol.2 No.12 p.5-8, December 10, 2002

  In such high-speed shooting, insufficient exposure is a problem. For example, at a shooting speed of 1 million frames / second, the exposure amount per frame is about 1/3000 compared to a normal video camera (30 frames / second). Therefore, conventionally, a strong continuous light source such as a halogen lamp or a metal halide lamp, a flash lamp capable of obtaining a strong light amount for a short time, or a pulsed laser light source synchronized with an imaging cycle has been used.

  However, the light from the halogen lamp and the metal halide lamp contains a large amount of infrared components, and because it uses a powerful light source, it emits a large amount of light. In some cases, this may alter or damage the object to be photographed and may affect the measurement results. In addition, since the flash lamp has a limited light emission time (usually about 1 msec), it cannot handle shooting for a relatively long time. Furthermore, there is a problem that time is required for charging after light emission, and the cycle of repeated light emission cannot be accelerated.

  In the case of a laser light source, these problems do not occur, but the apparatus is very expensive and large, and handling is complicated.

  The problem to be solved by the present invention is to provide a high-speed photographing system that can secure an exposure amount necessary for photographing without affecting a photographing object while being relatively inexpensive.

The high-speed imaging system according to the present invention made to solve the above problems is
a) A high-speed video camera that can output a sync signal synchronized with the shooting,
b) a light source using LEDs that can be turned on and off by the synchronization signal;
It is characterized by providing.

Another aspect of the high-speed imaging system according to the present invention is as follows:
a) a high-speed video camera capable of outputting a synchronization signal synchronized with the exposure timing of each shooting frame;
b) a light source using an LED that can be turned on and off by the synchronization signal;
It is characterized by providing.

  In the high-speed shooting system according to the present invention, a light source using an LED irradiates light to a shooting target in synchronization with shooting based on a synchronization signal output from a high-speed video camera. LEDs have less infrared components than halogen lamps and metal halide lamps, and even when the same amount of light is irradiated, the amount of heat generated by the object being photographed is small. In addition, since the response to input is good, it is possible to switch ON / OFF sufficiently following high-speed shooting of 1 million frames / second, and it is also possible to reduce the heat generation amount of the shooting target. Of course, a light source using an LED can be manufactured at a much lower cost than the laser light source.

  An example in which the high-speed imaging system according to the present invention is used for observing the state in which the test piece breaks during the tensile test of the resin material test piece will be described with reference to FIGS. The tensile tester 11 is connected to a control unit 12 for controlling it. The control unit 12 can output a corresponding signal from the signal output terminal at various times during the test (for example, at the start of pulling, when a predetermined displacement is reached, when a predetermined load is reached, etc.). The photographing system includes a high-speed video camera 13, an LED illumination 14 using an LED as a light source, and an illumination controller 15 that controls the LED illumination 14. The LED illumination 14 uses a high-power LED, and has a response speed of tens of microseconds or less. The high-speed video camera 13 transmits to the illumination controller 15 a shooting timing signal synchronized with the start and end times of one shooting and an exposure timing signal synchronized with the exposure start time of each frame being shot. On the other hand, the control unit 12 of the tensile tester 11 outputs the signal to the high-speed video camera 13.

  Next, a procedure for photographing the situation at the time of fracture of the test piece in the tensile test of the resin material test piece performed using this system will be described. First, the test piece 16 is set between the upper and lower chucks, and the operator presses the test start button of the control unit 12. The control unit 12 pulls the test piece 16 by moving the upper crosshead 11a of the tensile tester 11 upward at a predetermined speed. When the displacement of the crosshead 11a reaches a predetermined value, the control unit 12 transmits a predetermined displacement arrival signal to the high-speed video camera 13. Receiving this signal, the video camera 13 starts shooting. At the same time, an imaging start timing signal is transmitted to the illumination controller 15, and thereafter an exposure timing signal is continuously transmitted to the illumination controller 15 for each frame (FIG. 2 (a)). The high-speed video camera 13 ends the shooting when a predetermined shooting time tm elapses, and transmits a shooting end timing signal to the illumination controller 15.

  The illumination controller 15 starts power supply to the LED illumination 14 at the time when the imaging start timing signal is received. As a result, the LED is turned on, and the center of the test piece 16 is illuminated with a large amount of light as previously set. At this time, if a continuous light source such as a halogen lamp is used for illumination, in the case of a test piece such as a resin, the temperature rises and affects the result of the tensile test, but the LED illumination 14 as in this embodiment is used. Therefore, such external influence can be minimized.

  As described above, since the LED response speed is sufficiently high, it is generally desirable for the LED illumination 14 to perform intermittent illumination as shown in FIG. In this case, the illumination controller 15 intermittently supplies power to the LED illumination 14 in accordance with the exposure timing signal (FIG. 2 (a)) transmitted from the control unit 12 of the test machine 11. In the case of intermittent illumination, it is possible to increase the light emission luminance by passing a larger current compared to the case of continuous lighting.

  When the shooting speed of the high-speed video camera 13 becomes faster and the exposure time te per frame approaches the response speed of the LED, as shown in FIG. May be.

1 is a schematic configuration diagram of a high-speed imaging system of a tensile tester that is an embodiment of the present invention. 4 is a timing chart showing exposure timing and LED illumination emission timing in the high-speed imaging system of the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Test machine 11a ... Upper crosshead 12 ... Control part 13 ... High speed video camera 14 ... LED illumination 15 ... Illumination controller 16 ... Test piece

Claims (2)

a) A high-speed video camera that can output a sync signal synchronized with the shooting,
b) a light source using an LED that can be turned on and off by the synchronization signal;
A high-speed imaging system comprising: a) a high-speed video camera capable of outputting a synchronization signal synchronized with the exposure timing of each shooting frame;
b) a light source using LEDs that can be turned on and off by the synchronization signal;
A high-speed imaging system comprising:

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