ERROR PROPAGATION GRADATION GENERATION METHOD, GRADATION IMAGE REVELATION METHOD, ERROR PROPAGATION GRADATION IMAGE REVELATION METHOD AND GRADATION GENERATION ENCODER

摘要

PPROBLEM TO BE SOLVED: To reduce defects generated by an error propagation gradation generation method and arithmetic operations required for error propagation gradation generation. PSOLUTION: When the error of at least one of an object pixel 104 and one adjacent pixel adjacent to it exceeds a first error threshold (0), a first luminance threshold is selected in a threshold selection unit 112. Then, when the error of a separated neighboring pixel neighboring the object pixel 104 at a position separated more than the adjacent pixel exceeds a second error threshold (0), a second luminance threshold is selected and the first luminance threshold is not selected. Further, when the first and second luminance thresholds are not selected, a third luminance threshold is selected. The selected luminance threshold and the increase luminance of the object pixel 104 are compared in a threshold unit 110 and a binary signal for display or the like is outputted depending on whether or not the increase luminance exceeds the selected threshold. PCOPYRIGHT: (C)2004,JPO&NCIPI