Light detection device and light detection method

A light detection device detecting an incident position of light, the light detection device comprising:

• a plurality of pixels arranged two-dimensionally in a matrix and individually including a first photosensitive portion and a second photosensitive portion;
• a plurality of first wirings connecting a plurality of the first photosensitive portions to each other for every row;
• a plurality of second wirings connecting a plurality of the second photosensitive portions to each other for every column;
• a first reading unit arranged to read signal data through at least some of the plurality of first wirings;
• and
• a second reading unit arranged to read signal data through at least some of the plurality of second wirings,
• wherein the first reading unit has a reading pixel setting unit arranged to set, based on signal data read in a first frame, a pixel group for reading signal data in a second frame subsequent to the first frame from the plurality of pixels, and
• wherein the reading pixel setting unit has
• a dividing unit arranged to divide the pixel group reading signal data in the second frame into a plurality of groups by partitioning lions in which the plurality of pixels are arranged,
• a comparison unit arranged to compare signal data read from each of the groups between the groups divided off by the dividing unit, and
• a determination unit arranged to determine the pixel group for reading signal data in the second frame, based on comparison results of the comparison unit.