Patent Document ID: 5570434
Application ID: 08202843
Patent Status: 1

Claim One:
1. A circuit arrangement for recognizing a human face in a sequence of video pictures, each picture comprising a plurality of picture elements, wherein said sequence of video pictures is structured into blocks of said picture elements, respective blocks of two consecutive video pictures are subtracted from one another so as to form a difference picture comprising a plurality of difference blocks each comprising a plurality of picture elements each having a standard value, said standard values of said difference picture elements of each of said difference picture blocks are summed so as to form respective standard value sums, and said difference picture is mapped onto a status picture formed by status bits by comparing the standard value sum of each of said difference blocks to at least one threshold value and mapping those of said difference blocks having a standard value sum exceeding said at least one threshold value onto a status bit having a first binary value, and mapping those of said difference blocks having a standard value sum not exceeding said at least one threshold onto a status bit having a second binary value which is inverse to said first binary value, said circuit arrangement comprising: a) transforming means for transforming a first area of said status picture comprising first status bits having said first binary value into a unidimensional feature function in such a manner that the total number of these status bits within a line or a column of the status picture is determined; b) convolution means for standardizing said unidimensional feature function by convoluting said feature function with a second function so as to form a convolution integral and to supply a recognition signal when said current convolution integral corresponds to ideal values within predetermined tolerance limits; and c) marking means for determining, when said recognition signal is present, the center point of each line of said first area of said status picture so as to determine a vertical center axis, and to mark a plurality of points of said status picture located within a predetermined face area, which is cut in half by said center axis.