Patent ID: 7151844

Claim:
A method for detecting edges in an image using an image sensor that comprises a two-dimensional array of addressable pixels, with each of said pixels providing a data value indicative of a portion of the image sensed by that pixel, the method comprising the steps of: (a) sensing the image using the image sensor; and (b) carrying out the following steps for each of a number of selected pixels using a two-dimensional localized group of pixels surrounding each selected pixel, wherein each of the localized groups of pixels comprises a plurality of one-dimensional sets of pixels, each one-dimensional set being orthogonally offset from the other one-dimensional sets in the group: (b1) accessing a one-dimensional set of pixels contained within the localized group of pixels; (b2) reading the data values associated with the pixels accessed in step (b1); (b3) determining an intermediate data value using a smoothing function that is applied to the data values read in step (b2); (b4) repeating steps (b1) through (b3) for each of the one-dimensional sets of pixels contained within the localized group to thereby produce a set of said intermediate data values; and (b5) determining a final data value for the selected pixel using a differencing function that is applied to the set of intermediate data values; wherein step (b) further comprises processing the selected pixels sequentially such that, for each selected pixel, steps (b1) through (b5) are carried out for that selected pixel prior to carrying out any of the steps (b1) through (b5) for the next selected pixel.