A spread degree of a geometric feature in a surface of an object to be measured is estimated. The geometric feature is included in a geometric pattern, and will be observed in an image obtained by capturing the object on which the geometric pattern is projected. A parameter is set based on the estimated spread degree. Based on the parameter, a point on the geometric pattern is set in a captured image obtained by capturing the object to be measured on which the geometric pattern is projected. A three-dimensional position on the surface of the object corresponding to the set point is calculated.