Patent attributes
A three-dimensional imaging device includes a distance image acquiring unit configured to acquire distance images by switching exposure conditions; an effective pixel count calculation unit that calculates an effective pixel count; an ineffective pixel identifying unit that identifies ineffective pixels; and an exposure condition adjusting unit that sets the exposure conditions. The exposure condition adjusting unit sets a reference exposure condition, determines whether a reference effective pixel count is equal to or less than a first threshold value, and, in response to the reference effective pixel count being equal to or less than the first threshold value, sets an additional exposure condition that maximizes a total effective pixel count of a total distance image, and repeats additional setting of the additional exposure condition using the total distance image as a new reference distance image until the total effective pixel count becomes larger than the first threshold value.