초록 ▼

A method and apparatus for correlating two signals representing a live image and a reference image are disclosed. The reference signal is processed to provide a polarity bit and mask bit for each pixel position in the reference image. The processed video signal is stored in a memory 20 and used in a

A method and apparatus for correlating two signals representing a live image and a reference image are disclosed. The reference signal is processed to provide a polarity bit and mask bit for each pixel position in the reference image. The processed video signal is stored in a memory 20 and used in a convolver and summer section 18 in which the polarity bits between the reference and live images are gated by gate 17 and are used in generating a correlation output from summer 23. However, the polarity bits do not affect the correlation output if the logical output from gate 19 is of a given state which occurs if the associated mask bits indicate that the gradient value at the particular pixel position does not exceed certain minimum threshold values.

대표청구항 ▼

In a method of correlating two input signals associated with a live image and a reference image, the improvement which includes the steps of: (a) processing at least the reference image associated signal to provide a polarity bit and a mask bit for each pixel position therein, the value of the mask

In a method of correlating two input signals associated with a live image and a reference image, the improvement which includes the steps of: (a) processing at least the reference image associated signal to provide a polarity bit and a mask bit for each pixel position therein, the value of the mask bit being one digital state defining an off condition if the amplitude of the signal falls between two preselected threshold levels thereby substantially filtering out noisy pixels with amplitudes between the two threshold levels, and being of an opposite state defining an on condition if the amplitude is outside of the threshold levels, the value of the polarity bit being one digital state if the amplitude is positive with respect to a predetermined reference level and being of an opposite state if the amplitude is negative with respect to a predetermined reference level at that pixel position; and (b) using the polarity and mask bits of the processed reference signal to generate a correlation output wherein the pixel positions with a mask bit in the on condition are used in the correlation while the pixel positions with a mask bit in the off condition are not used in the correlation process, thereby producing a correlation output that is minimally affected by noise in the input signal.