Patent ID: 6731868
Filing Date: 2004-05-04
Classification: G02B

Abstract:
A distance measuring apparatus, comprising:an AF data generating device which forms images of light from a distance measurement object on a pair of line sensors comprising a plurality of light-receiving elements and generates a pair of AF data for correlation value calculation according to signals obtained from the plurality of light-receiving elements; a first AF data obtaining device which obtains a pair of AF data from a pair of employed sensor ranges for use in distance measurement in the pair of line sensors; a second AF data obtaining device which determines a pair of window ranges for obtaining the pair of AF data for use in the correlation value calculation in the pair of employed sensor ranges, and sequentially obtains the pair of AF data for use in the correlation value calculation while shifting the pair of window ranges to obtain a highest correlation in the pair of employed sensors; a first contrast determining device which determines whether or not the pair of AF data obtained by the first AF data obtaining device have a first predetermined necessary contrast for a distance measurement; a correlation value calculating device which calculates correlation between the pair of AF data obtained by the second AF data obtaining device only when the first contrast determining device determines that there is the first predetermined necessary contrast; a second contrast determining device which determines whether or not the AF data in the pair of window ranges when a highest correlation is obtained in the correlation obtained by the correlation value calculating device have a second predetermined necessary contrast for the distance measurement; and a distance measurement object distance calculating device which calculates a distance from the distance measurement object according to a shift amount of the pair of window ranges when the highest correlation is obtained only when the second contrast determining device determines that there is the second predetermined necessary contrast.