Patent ID: 7898689
Filing Date: 2011-03-01
Classification: H04N

Abstract:
1. A controller which is connectable to a print engine, the controller comprising: an image processing circuit operable to convert first data to second data to be output to the print engine; a CPU operable to input the first data to the image processing circuit; and a memory storing a gradation conversion table in which M-bit intermediate gradation data are correlated with each of N-bit input gradation data, wherein: the image processing circuit comprises: an input gradation converting circuit, operable to convert each of the input gradation data into the M-bit intermediate gradation data by using the gradation conversion table and output the converted M-bit intermediate gradation data; and a diffusion gradation converting circuit, operable to convert each of the intermediate gradation data outputted from the input gradation converting circuit into N-bit output gradation data and output the converted N-bit output gradation data, the diffusion gradation converting circuit acquires a uniform random number Rnd in the range of −SFT/2 to SFT/2 and outputs [X+Rnd+0.5] as the output gradation data for each of the intermediate gradation data in which X obtained by dividing a value of the intermediate gradation data by 2