Abstract: A technique for estimating an unsampled color data on the basis of plural color data sampled by a line image sensor. The sensor includes at least two types of color filters such as a red filter and a green filter. Those filters are alternately arranged pixel by pixel in a line of pixels so that A-type color data which corresponds to green data is sampled from a target pixel and plural B-type color data which correspond to red data are sampled from neighbor pixels neighboring the target pixel. An unsampled B-type color data of the target pixel is estimated by synthesizing the sampled A-type color data of the target pixel and the sampled B-type color data of the neighbor pixels.

Abstract: The position of the same point on each of the images of a single object formed by the imaging means of an endoscope is detected, and shift maps between the respective images are formed using the detected positions. Each of the imaging positions of the imaging means is estimated from the shift maps, and a relative shape of the object is then estimated from the imaging positions. Since a relative shape of the object is estimated using the correlation between the respective images, a relative shape of the object can be estimated even when not only the imaging means but also the object are moved. An absolute shape of the object can also be estimated using a length as a reference value.