Patent ID: 7474415

Claim:
A measurement method of three-dimensional profiles using subpixel localization with color gratings and picture-in-picture switching on a single display, comprising the steps of: preparation step, preparing a projection apparatus, a photographic apparatus, and a central processing unit; projection step, starting the projection apparatus, which emits grating light towards a workpiece under measurement, the grating light having a plurality of grating stripes with identical contrast and forming a grating image on the workpiece under measurement and the grating image being comprised of a plurality of stripes with identical contrast; image extraction step, starting the photographic apparatus, and extracting the grating image from the workpiece under measurement; image fine-tuning step, the central processing unit having a display, which can display a first displaying part and a second displaying part simultaneously, the first displaying part being used for adjusting directly the focus, aperture, and depth of field of the photographic apparatus, the first displaying part being shut down from the display and the display being switched to display the grating image using the second displaying part with full screen after the grating image is shown distinctly on the first displaying part; image processing step, the central processing unit performing image analysis on the grating image, eliminating noises, and thinning the stripes; and reconstruction step, the central processor using parabolic curve distribution analysis for giving the minimum and the maximum of the grey-scale distribution with more accuracy, each pixel in the grating image with thinned stripes being given, thinned stripes being used for approximation with parabolic curve distributions to give the maximum curvature of the stripes, and the three-dimensional profiles of the workpiece under measurement being given with phase-shift technology and phase reconstruction.