1. A method for calculating a feature descriptor on a single instruction, multiple data (SIMD) processor, comprising: storing an entire histogram table in a register file on the SIMD processor; generating histogram bin indexes in a first register on the SIMD processor; generating weights in a second register on the SIMD processor; and updating the entire histogram table in the register file based on the histogram bin indexes and the weights without storing any histogram bin in the histogram table to memory, wherein histogram bins in the histogram table are updated in parallel with a single instruction in a single cycle of the SIMD processor.