1. An apparatus comprising a memory and at least one processor that executes a program to function as: a region extraction unit configured to extract a first region having predetermined color information from a first image sensed by an imaging apparatus in a first viewpoint and a second region having the predetermined color information from a second image sensed by an imaging apparatus in a second viewpoint different from the first viewpoint; a first determination unit configured to determine whether a first area of the extracted first region in the first image is larger than a first threshold value, and determine whether a second area of the extracted second region in the second image is larger than a second threshold value; an obtaining unit configured to obtain first intersection points where a first line set in the first image intersects first pixels of an outline of the first region, and the first determination unit determines that the first area of which in the first image is larger than the first threshold value, and obtain second intersection points where a second line set in the second image intersects second pixels of an outline of the second region, and the first determination unit determines that the second area of which in the second image is larger than the second threshold value; an attribute determination unit configured to determine first attributes which indicate whether the first pixels at the obtained first intersection points are on a right side or on a left side of the first region in the first image, and determine second attributes which indicate whether the second pixels at the obtained second intersection points are on a right side or on a left side of the second region in the second image; a second determination unit configured to determine whether the first attributes of the first intersection points on the first line set in the first image match with second attributes of the second intersection points on the second line set in the second image; a correspondence processing unit configured to obtain corresponding points between the first image and the second image based on a result of the second determination unit; and a calculation unit configured to calculate at least a depth value of an object based on obtained corresponding points.