1. A three dimensional measurement apparatus comprising: a projection unit configured to project a pattern including a measurement pattern and a feature pattern onto an object; an image capturing unit configured to capture an image of the object onto which the pattern is projected; a grouping unit configured to divide the image captured by said image capturing unit into a plurality of regions using the measurement pattern in the pattern and a plurality of epipolar lines determined based on a positional relationship between said projection unit and said image capturing unit, and to group predetermined regions among the plurality of divided regions; a feature recognition unit configured to recognize the feature pattern based on a difference in the feature pattern between the predetermined regions; and a three-dimensional shape calculation unit configured to calculate a three-dimensional shape of the object based on the feature pattern recognized by said feature recognition unit.