Patent ID: 9524432
Filing Date: 2016-12-20
CPC Classification: G06K,G06T

Claim Text:
1. A computer-implemented method, the method comprising: identifying a candidate corner feature in a first image, the candidate corner feature including a set of pixels from the first image; determining a center pixel from the set of pixels; selecting, from the set of pixels, a subset of pixels, each pixel from the subset of pixels being at a respective distance from the center pixel, wherein the subset of pixels comprises a ring shape that surrounds the center pixel; downscaling the set of pixels from the first image, the downscaled set of pixels representing a second layer of a pyramid and the set of pixels representing a bottom layer of the pyramid; determining a first derivative value based at least in part on of a weighted sum of intensities of respective pixels from a right side of the downscaled set of pixels and intensities of respective pixels from the left side of the downscaled set of pixels; determining a second derivative value based at least in part on of a second weighted sum of intensities of respective pixels from an upper side of the downscaled set of pixels and intensities of respective pixels from a bottom side of the downscaled set of pixels; determining an orientation angle using at least an arctangent function on the first and second derivative values; shifting values of a subset of pixels from the downscaled set of pixels based at least in part on the orientation angle, the subset of pixels comprising a ring that surrounds a respective center pixel of the downscaled set of pixels; and confirming a corner feature of the first image based at least in part on: providing the confirmed corner feature to at least one object recognition process.