Abstract: The present invention discloses an apparatus for regulating chamber pressure in a process chamber by a closed-loop control method utilizing a pressure sensor, a pressure controller and an inverter for regulating the rotational speed of an exhaust blower such that the exhaust pressure in a factory exhaust conduit can be substantially controlled at a constant value. The present invention novel method and apparatus allows a more stable chamber pressure to be maintained in an APCVD or LPCVD chamber, while substantially reduces the possibility of particulate contamination on a throttle valve that is mounted juxtaposed to the process chamber and thus minimizing any back-fill contamination problems.

Abstract: A mask matching approach to detect shot changes in MPEG coded video uses reference ratio variances of macroblocks between MPEG coded frames. A function is designed to quantize the results into shot change probability values. Moreover, a conversion function modifies this probability computation to minimize misdetection and loss of detection under unusual image pattern situations. A shot change probability threshold is defined for the video to be examined. When a frame's modified shot change probability exceeds this threshold, the frame is considered to contain a shot change. With this approach, processing time is reduced by evaluating MPEG coded data directly, rather than the raw video.