_cmp_offsets = function(pixel, step, pattern_size) {
            var k = 0;
            var offsets = offsets16;
            for( ; k < pattern_size; ++k ) {
                pixel[k] = offsets[k<<1] + offsets[(k<<1)+1] * step;
            }
            for( ; k < 25; ++k ) {
                pixel[k] = pixel[k - pattern_size];
            }
        }
@author Eugene Zatepyakin / http://inspirit.ru/

This is FAST corner detector, contributed to OpenCV by the author, Edward Rosten.