Patent ID: 6031928
Filing Date: 2000-02-29
Classification: G06T

Abstract:
Metrological apparatus for determining the surface texture or roughness of a workpiece comprising:means for measuring the height of the surface at a plurality of different points on the surface to produce a corresponding plurality of height values;processing means for:(i) calculating gradient data at a plurality of said different points on the surface from said height values,(ii) adjusting said gradient data dependent upon a selected angle of illumination, and(iii) generating image data by combining the corresponding values of said adjusted gradient data and said height value for a plurality of said different pointswherein said processing means is arranged to combine said corresponding values of said adjusted gradient data and said input height value to generate said image data according to the relationshipImage.sub.-- Data(x,y)=S*Height(x,y)+T*Gradient(x,y)where Image.sub.-- Data (x,y), Height (x,y) and Gradient (x,y) are the values of said image data, said input height and said adjusted gradient data at a point (x,y) on the surface respectively and S and T are weighting coefficients; andmeans for forming an image in accordance with said image data.