Patent ID: 7595893

Claim:
A shape measurement method for measuring a shape of an object to be measured, which has a substantially rotating symmetric shape, comprising: placing an aperture having an opening larger than an outer shape of the object to be measured and the object to be measured on an optical axis; taking an image generated by light projected to the object to be measured, by using an image pickup unit; and calculating one cross-sectional shape of the object to be measured based on a light intensity distribution of the image taken by the image pickup unit, wherein in the calculating, a shape of the opening of the aperture is compared with a shape of an opening of an image of the aperture, and the one cross-sectional shape of the object to be measured is calculated by correcting the shape of the image of the object to be measured based on a result of a comparison between the shape of the opening of the aperture and the shape of the opening of the image of the aperture.