A simple detection method of movement of clouds at the sky

摘要

There is a set of methods for a cloud on sky detection. The common passive examination of cloud presence is realized with digital post-processing of picture that was taken with a device that enables full-sky photography. As the camera is set in automatic mode the results of examinations depends on lighting conditions. Therefore up-today critical real-time applications are supported with laser or microwave devices that generate specific probing beams. The common feature of the mentioned devices is the high cost of equipment. Thus, the development of a sensing device that consists of standard modules and is intended for real-time measurements of the movement of clouds at skyline has been initiated. Proposed sensing device construction bases on a matrix of photodiodes integrated in the VEML6040 chip. The measurement results of the VEML6040 are analyzed with camera pictures. Obtained results show that filtered first derivative of ratio of blue to whole spectrum signal can be used to set proper thresholds that generate automatically signal of cloud movement detection.