Patent ID: 9288369
Filing Date: 2016-03-15
CPC Classification: H04N

Claim Text:
1. A displacement estimation method for a displacement estimation device on a working surface, the estimation device comprising an amplifier and an image sensor, the method comprising: acquiring an image frame of the working surface with sampling parameters, wherein the sampling parameters comprise an amplification gain of the amplifier and an exposure time of the image sensor; determining a number of peaks according to the sampling parameters by referring to a lookup table which stores a previously constructed relationship between the sampling parameters and the number of peaks, wherein the sampling parameters in the previously constructed relationship include values of the amplification gain and the exposure time, wherein the previously constructed relationship is obtained by acquiring test image frames with the image sensor while varying the sampling parameters, and wherein the test image frames include an image of a uniformly distributed light source and do not contain an image of any working surface; calculating a total number of peaks of the image frame, wherein a peak is a pixel having a gray level larger or smaller than, by a predetermined value, gray levels of two adjacent pixels thereof in a same row or a same column of the image frame; setting a quality threshold directly as a ratio or an offset of the determined number of peaks, wherein the quality threshold is larger than the determined number of peaks; comparing the total number of peaks and the quality threshold; when the total number of peaks is larger than the quality threshold, estimating a displacement of the displacement estimation device based on the image frame; and when the total number of peaks is smaller than the quality threshold, ignoring the image frame.