| 摘要 |
PURPOSE:To achieve only the removal of a texture noise effectively by setting the best threshold level for a sepcific picture-element area and converting a target picture element into a binary signal by using the threshold level. CONSTITUTION:An input picture signal BS obtained by scanning a picture, element by element and by multileved quantization is stored in a multilevel information storing circuit 1. The maximum and minimum values of the stored contents are detected by level detecting circuits 2 and 3 respectively and then sent to a subtracter 4 to calculate a difference (t), which is compared with a comparison criterion (t2) by a comparator 5. Simultaneously, the contents B of the circuit 1 are supplied through a density-classified difference sum storing circuit 7 to a maximum-value detecting circuit 8, where the maximum value sigmajmax of the density-classified total difference sum sigmaj is detected. Then, the best threshold level L set by the circuit 9 is supplied to a binary-coding circuit 10, where it is compared with the density level of the target picture element from the circuit 1 through a delay circuit 11 to generate a binary-coding output. |
