High-speed Charge-coupled Device Video Research Articles

Real-time lock-in imaging by a newly developed high-speed image-processing charge coupled device video camera

Real-time lock-in imaging with high-frequency modulation (up to 16 kHz) was successfully performed at high spatial resolution (640×480 pixels) using a newly developed high-speed image-processing charge coupled device (CCD) video camera. To achieve high-resolution lock-in imaging, the high-speed image-processing CCD video camera incorporates a high-definition TV image sensor that uses a high-definition frame-interline-transfer (FIT) CCD architecture. A novel FIT-CCD driving method, in which vertical CCD shift registers are utilized as a temporary frame memory, enables lock-in imaging at a modulation frequency in excess of the video frame rate (30 Hz). Furthermore, since the high-speed image-processing CCD video camera has a function for subtracting images taken with high-frequency modulation, a lock-in image with no background contrast can be observed in real time. The phase detection function for lock-in imaging, when coupled with real-time image processing using the high-speed image-processing CCD video camera, makes it possible to dynamically observe the phase distribution in a two-dimensional area. As a demonstration of the real-time lock-in imaging, the wave pattern that appears on the surface of water was successfully visualized by a real-time lock-in imaging system that uses the high-speed image-processing CCD video camera.

RDS and IRDS filters for high-speed CCD video sensors

In this brief, we present two filters called "reflection delayed noise suppression" (RDS) and "integration reflection delayed noise suppression" (IRDS) which are useful to increase dynamics of video charge-coupled device (CCD) cameras. The RDS is a band-pass filter built with a parallel short-circuited line. It significantly lowers the most important noise, called reset noise. Unfortunately, this signal processing unit increases the contribution of thermal fluctuations by at least 3 dB. To overcome this disadvantage, a reset low-pass filter can be added to the RDS cell, which leads to the IRDS method. For both methods, we will describe the principle and compare their effects in a theoretical way, and by experimentation on sensing-node amplifier and reset noise in the CCD sensor.

Physical and theoretical aspects of a new vacuum arc control technology-self arc diffusion by electrode: SADE

Our new vacuum arc control technology SADE doubles the high current interruption capability of our conventional axial magnetic field technology. First, we describe the vacuum arc motion behavior recorded by a high speed charge-coupled device video camera. This arc behavior is closely related to axial magnetic field intensity. In particular, it depends on the profile of the externally generated axial magnetic field. The anode spot is likely to move to the highest magnetic field intensity. Second, we describe analytical results for concentration of vacuum arc at the anode side contact surface. This analysis implies the possibility of an ideal magnetic field profile and intensity for vacuum arc control. Finally, we describe experimental results for vacuum arc control compared with the physical and theoretical results mentioned above, and we show a practical electrode configuration for vacuum interrupters and its application in a high current interruption experiment.