| 摘要 |
PURPOSE:To remove noises by adopting the merits of an edge extracting method for finding out the product sum of a mask pattern having a supporessing field and detecting zero-crossing and an edge extracting method for extracting a part having larger absolute value of a spatial partial derivative of 1st degree. CONSTITUTION:An original picture is stored in a picture memory 1 and an extracted edge picture is stored in a picture memory 6. A picture scanning means 2 reads out 7X7 picture elements e.g. simultaneously and a product sum means 7 calculates the product sum of patterns having a suppressing field at its periphery. the output of the means 7 is compared with the code of the product sum result of a picture element adjacent to the code by a zero-crossing detecting means 8, and when both the results are different each other, a zero-crossing detecting signal is outputted from the means 8. On the other hand, a product sum means group 3 executes the product sum of four mask patterns to find out the spatial partial derivative of 1st degree for 3X3 center picture elements out of the partial picture. A comparing means 5 compares the output values, and when the output value is larger, outputs an edge area signal. An edge discriminating means 9 selects the real edge on the basis of AND between the zero-crossing output signal and the edge area signal. |
