The invention discloses an
image tracking system and an
image tracking algorithm for a double-cylinder multi-FOV (
field of view) sun
photometer. The
image tracking system for the double-cylinder multi-FOV sun
photometer comprises an image forming photic cylinder, a CCD (charged coupled device)
image sensor, an image capturing module, a
movement control module, an industrial
personal computer, and a rotary table. The
movement control module is controlled by the industrial
personal computer to enable the rotary table to correctly return to an initial position in
two degrees of freedom in horizontal and elevated directions. After a broad-tracking command is issued by a user via the industrial
personal computer, the rotary table is controlled by the
movement control module to enable the image forming photic cylinder to align to the sun, parallel
sunlight forms an image on a
target surface of the CCD via the image forming photic cylinder, the image capturing module is commanded, by the industrial personal computer via a procedure, to capture a sun image output by the CCD
image sensor and transmits the sun image to the industrial personal computer, then an accurate-tracking command is issued by the industrial personal computer so that the movement control module can control the rotary table to accurately track the sun, and the tracking accuracy is higher than one arc-second. By the aid of the image
tracking system and the image tracking
algorithm for the double-cylinder multi-FOV sun
photometer, the limitation problem that a conventional sun photometer, in the presence of uneven clouds, cannot accurately track the sun by utilizing distribution of four-quadrant
light intensity is solved.