Photo-detection system comprising photo-detection apparatus including light-shielding film, optically-coupled layer, and photodetector and arithmetic circuit

A photo-detection system comprising:

• a photo-detection apparatus;
• and
• an arithmetic circuit,
• the photo-detection apparatus including:
• a light-shielding film including light-transmitting regions and light-shielding regions, the light-transmitting regions and the light-shielding regions being alternately arranged in at least a first direction within a plane,
• an optically-coupled layer facing the light-shielding film, the optically-coupled layer including a grating which generates a propagating light that propagates in the first direction and a transmitting light that transmits the optically-coupled layer when incident light of a predetermined wavelength enters the light-transmitting regions, and
• a photodetector having an imaging area, the photodetector including first photo-detection cells and second photo-detection cells, the first photo-detection cells and the second photo-detection cells being arranged on the imaging area, each of the first photo-detection cells corresponding to at least one of the light-transmitting regions, each of the second photo-detection cells corresponding to at least one of the light-shielding regions, and
• the arithmetic circuit generating, based on first signals that are obtained from the first photo-detection cells and second signals that are obtained from the second photo-detection cells, third signals each representing coherence of light having entered a position of each of the first and second photo-detection cells,
• the arithmetic circuit generating at least one selected from the group consisting of an average value of the third signals, a standard deviation of the third signals, a ratio between the standard deviation and the average value, and a ratio between an average value of a first portion of the third signals and an average value of a second portion of the third signals in positions of at least a part of the first photo-detection cells and the second photo-detection cells that are included in a region of the imaging plane, wherein:
• the first portion of the third signals is based on light having entered the positions of the first photo-detection cells, and
• the second portion of the third signals is based on light having entered the positions of the second photo-detection cells.