| 摘要 |
PURPOSE:To attain high speed processing with a simple processing step, by calculating the projected density in two orthogonal directions with regard to a digital picture and detecting the position of peak exceeding the threshold value after the application of convolution. CONSTITUTION:A CPU108 starts raster scanning of the digital picture stored in a picture memory 100 to a scanning circuit 101. An adder 102 adds accumulatingly the number of black picture elements by X and Y directions of a picture read from the memory 100 to calculate the projected density H(x), H(y). The densities H(x), H(y) outputted from the adder 2 are stored in line memories 103, 104. Convolution circuits 105, 106 uses the densities H(x), H(y) of the memories 103, 104 and applies the convolution processing. A comparator 107 compares the outputs H'(x), H'(y) of the circuits 105, 106 with a prescribed threshold value, detects addresses x, y exceeding the H'(x), H'(y) to detect the presence of a frame in the raster scanning area. |
