Method for measuring object surface appearance based on digital picture method

Abstract

The invention discloses a method for measuring an object surface appearance based on a digital picture method. The method comprises the steps of demarcating a focus distance-focus evaluation function curve and rebuilding three-dimensional appearance of the object surface, wherein the step of demarcating the focus distance-focus evaluation function curve comprises taking the areas with same size around the pixels in a same X and Y coordinate in each picture, calculating a focus evaluation function of the areas, corresponding the focus evaluation function to the focus distance of each picture in the picture order, and the step of rebuilding three-dimensional appearance of the object surface comprises taking a picture at any position in front of the object, taking one area around the pixels in the picture, calculating the focus evaluation function of the area, corresponding to the demarcated curve, and obtaining a distance value corresponding to the focus evaluation function of the area when the function is in an effective range. The distance difference between the distance and the maximum focus evaluation function corresponding to the horizontal ordinate distance is the height value of the pixels.

Description

technical field [0001] The invention relates to a method for non-contact measuring the surface topography of an object, in particular to a method for measuring the surface topography of an object based on a digital image method. Background technique [0002] There have been many related researches at home and abroad on the three-dimensional topography measurement of the object surface based on the digital image method, involving optics, testing technology, image processing and other fields. Because the depth of field of the imaging device is limited, a photo taken at the same position is different. The definition of different places is different. The current 3D shape measurement based on the digital image method is actually a research on focus extraction, such as figure 1 As shown, the basic principle is to obtain a sequence of images by adjusting the Z-axis position of the camera, so that the entire sequence covers all the Z-axis direction information of the object in the c...

AI Technical Summary

Problems solved by technology

[0005] The problem with the above-mentioned three-dimensional surface topography measurement technology based on digital image method is that the Z-axis position of the camera needs to be adjusted for each measurement, and many photos are taken to form a sequence of images, so that the entire sequence covers all the Z-axis of the object in the camera. Orientation information only works, which makes the measurement work cumbersome and complicates the subsequent reconstruction work

Images