Patent ID: 6757065
Filing Date: 2004-06-29
Classification: G01B

Abstract:
A method for determining a surface illuminated by incident light by recording the intensity (I1(x,y)) in light reflected from the surface in a first image thereof and by recording the intensity (I1(x,y)) in light reflected from the surface in a second image thereof, taken with another angle of illumination and complementary to the first image, comprising:recording the intensity of only diffusely reflected light over the surface in the first and second images; determining the difference between the recorded intensities of diffusely reflected light over the surface in the first and second images in order to obtain a representation that emphasizes variations in gradient of the surface; calculating the derivative of the area by fxâ€²&af;(x,y)&TildeTilde;1tan&it;â€ƒ&it;Y&it;I1&af;(x,y)-I2&af;(x,y)I1&af;(x,y)-I2&af;(x,y)where Y is the angle of incidence of the light; andFourier transformation of the derivative and multiplication thereof by a Wiener filter in order to suppress noise in the recorded intensities.