The process is composed of three stages. The average of the remaining boxes is the background value. In order to allow a sufficiently good estimate of the background, only images of size 128x128 pixels or larger should be used.
Maximum accuracy is obtained by using full resolution images.
See the background example for information on tweaking the calculation to get a good background estimate. If the background is overestimated, sources may be lost. If it is underestimated, the probability that there will be false detections increases. It is important that the background calculation be as accurate as possible. If a chat level of at least 15 is set, the final threshold value will be printed.