Patent ID: 9208584
Filing Date: 2015-12-08
Classification: G06T

Abstract:
1. A method for describing an image, comprising: transforming an image from a blue green red, BGR, color space into a Gaussian derivative color model; and transforming the image from the Gaussian derivative color model into an optical reflection invariant color space, wherein the process of transforming the image from the Gaussian derivative color model into the optical reflection invariant color space comprises: determining, for each of a plurality of pixels on the image, color channels of the each of the plurality of pixels corresponding to the optical reflection invariant color space according to a first coefficient and a second coefficient of the each of the plurality of pixels in the Gaussian derivative color model; wherein after the image is transformed from the Gaussian derivative color model into the optical reflection invariant color space, the method further comprises: building a Laplacian of Gaussian, LoG, pyramid for the image in the optical reflection invariant color space and transforming the LoG pyramid into a Difference of Gaussian, DoG, pyramid; determining a plurality of local extremes according to the DoG pyramid, wherein each of the plurality of local extremes includes a first local extreme in the scale direction, a second local extreme in the X direction and a third local extreme in the Y direction; and determining, for the each of the plurality of local extremes, a key pixel according to the first local extreme, the second local extreme and the third local extreme; wherein after the key pixels for the plurality of local extremes are determined, the method further comprises: determining, for each of the key pixels, a gradient description range corresponding to the each of the key pixels according to the first local extreme of the each of the key pixels; and determining an eigenvector corresponding to the each of the key pixels according to the gradient description range; wherein the gradient description range corresponding to each of the key pixels is a circular area centered at the each of the key pixels and includes another plurality of pixels, and the radius of the gradient description range corresponding to the each of the key pixels is determined in the formula of: wherein R represents the radius of the gradient description range corresponding to the each of the key pixels, α