Patent ID: 8195041

Claim:
An exposure control unit that controls the exposure of an imaging apparatus, the exposure control unit comprising: a photometer that comprises a plurality of photometric zones on a light-receiving surface, an optical image of an object to be imaged by the imaging apparatus being made incident on the light-receiving surface of the photometer, each of the photometric zones detecting a partial quantity of the light incident on each photometric zone; a designator that designates a plurality of the photometric zones one by one as a target zone, the designator designating a plurality of the photometric zones arranged in predetermined positions with respect to the target zone as neighboring zones; a first calculator that calculates a first difference between light values, the first difference of light values being a difference between a partial value of light in the target zone and the partial value of light in the neighboring zones, the partial value of light varying according to the partial quantity of light; a first counter that counts a first determination number for each target zone, the first determination number being the number of neighboring zones with the first difference of light values that is less than a first threshold for the temporarily designated target zone; a selector that selects the target zone of which the first determination number is greater than a second threshold; a second calculator that calculates a categorization value on the basis of the partial value of light of the target zone selected by the selector, the categorization value being used for categorization of the target zone; a categorizer that categorizes a target zone having a partial value of light that is less than the categorization value into a low-luminous zone among the target zones selected by the selector, and that categorizes a target zone having the partial value of light that is greater than the categorization value into the high-luminous zone among the target zones selected by the selector; and an exposure controller that controls an exposure of the imaging apparatus on the basis of the partial value of light of at least one of the low-luminous zone and the high-luminous zone, wherein the second calculator calculates a categorization value of a whole of the light-receiving surface on the basis of the amount of light in one or more of the targets that are selected by the selector.