Development of High-Speed Video Cameras and Study on Dynamic Deformation Behavior of Materials

为了研究材料的高速变形，研制了采用固态图像传感器的高速数字摄像机。使用三种类型的图像传感器。它们是具有光学黑区的MOS型图像传感器、没有光学黑区的MOS型图像传感器和具有光学黑区的CCD图像传感器。帧速度和帧大小由个人计算机控制。当选择图像传感器的小扫描区域时，帧速度变得更快;然而，相应的分辨率降低。理想的最大帧速度约为1200万帧/秒。由于噪声和控制信号的宽脉冲宽度，实际最大速度为420千帧/秒。通过使用A/D转换器将图像信号存储在IC存储器中。通过循环重写将图像信号发送到相同的IC存储器。如果在现象完成之后输入触发，则容易捕获触发之前的期望图像。不 ...更多信息 为了测量材料的变形，采用了作者提出的傅里叶变换云纹网格法（FTMGM）。在该方法中，通过使用正弦亮度分布的相位非常自然地执行条纹或光栅线之间的插值，该正弦亮度分布是从条纹或光栅线的图像的傅立叶频谱的第一谐波获得的。该方法过程简单，完全自动化，无需主观处理。因此，这种分析可以排除人为误差，以便精确测量位移，应变，速度，应变率和高度。尽管关于距离和时间的双重微分，但是由于在FTMGM中自然地执行数据的平滑，所以精度高。在微机和工作站上开发了FTMM程序，并进行了橡胶管中应力波传播和橡胶板振动等实验。这可能是第一份测量应变率分布的报告。少

In order to study high-speed deformation of materials, high speed digital video cameras are developed by using solid-state image sensors. Three types of image sensors are used. These are a MOS type image sensor with an optical black area, a MOS type image sensor without the optical black area and a CCD image sensor with an optical black area. The frame speed and frame size are controlled by a personal computer. When a small scanning-area of the image sensors is selected, the frame speed becomes faster ; however the corresponding resolution decreases. The ideal maximum frame speed is about 12 millions frames/sec. The practical maximum speed is 420 thousands frames/sec because of noises and the wide pulse-width of the control signal. The image signal is stored in IC memories by using an A/D convertor. The image signal is sent to the same IC memories by cyclically rewriting. If a trigger is ent after the phenomenon is completed, the desired images before the trigger are easily captured. T … More he recording time is about one second.In order to measure deformation of materials, the Fourier transform moire and grid method (FTMGM), which has been developed by the authors, is used. In this method, the interpolation between fringes or grating lines is performed very naturally by using the phases of the sinusoidal brightness distribution, which is obtained from the first harmonic of the Fourier spectrum of the image of the fringes or grating lines. The process of this method is simple and completely automated, without subjective process. Therefore this analysis can exclude human errors so that accurate measurements of displacement, strain, velocity, strain rate and height are performed. In spite of double differentiation with respect to distance and time, the accuracy is high because the smoothing of data is naturally performed in the FTMGM. The program of the FTMGM is developed on personal computers and workstations.Some experiments such as stress wave propagation in a rubber tube and vibration of a rubber plate are performed. These may be the first report measuring strain rate distribution. Less