Abstract: Many conventional video processing algorithms attempting to detect human presence in a video stream often generate false positives on non-human movements such as plants moving in the wind, rotating fan, etc. To reduce false positives, a technique exploiting temporal correlation of non-human movements can accurately detect human occupancy while reject non-human movements. Specifically, the technique involves performing temporal analysis on a time-series signal generated based on an accumulation of foreground maps and an accumulation of motion map and analyzing the running mean and the running variance of the time-series signal. By determining whether the time-series signal is correlated in time, the technique is able to distinguish human movements and non-human movements. Besides having superior accuracy, the technique lends itself to an efficient algorithm which can be implemented on low cost, low power digital signal processor or other suitable hardware.

Abstract: It is often desirable to transmit data between circuits or components operating at a relatively high voltage and circuits operating at a relatively low voltage. Such a task can be performed by use of an isolator. Some isolator designs use magnetic coupling to transfer the data as this is more robust against inadvertently transmitting high voltage transients than capacitor based isolators. However it is often desirable to encode the data for exchange across the transformer of the isolator and decode after transmission across the transformer. This requires power for the encoding and decoding circuits. To ensure both sides are powered, power may be transferred by another transformer. The transformer primary is driven by an oscillating signal. The system disclosed in some embodiments herein varies the frequency of the oscillating signal to mitigate the risk of it interfering with other circuits or systems associated with the isolator.