Image processing device, image processing method, program, recording medium and integrated circuit

An image processing method for diffusing an error generated at a target pixel when converting a first video signal having M tone levels to a second video signal having N tone levels by restricting the tone levels of the first video signal to the N tone levels, where N<M, and M and N are natural numbers, the method comprising:

• obtaining pixel variation information based on a degree of pixel value variation using pixel values in a predetermined area consisting of the target pixel included in a first frame that is formed using the first video signal and two or more neighboring pixels of the target pixel;
• determining, based on the pixel variation information, an intra-frame error distribution rate that is used to distribute the error generated at the target pixel within the first frame and an inter-frame error distribution rate that is used to distribute the error generated at the target pixel to a second frame different from the first frame, and determining, based on the intra-frame error distribution rate and the inter-frame error distribution rate, an intra-frame error distribution weight that is used to weight each of the neighboring pixels that are included in the first frame and an inter-frame error distribution weight that is used to weight a target pixel that is included in the second frame and is at a position identical to a position of the target pixel included in the first frame and neighboring pixels that are included in the second frame and are at positions identical to the neighboring pixels included in the first frame;
• and
• distributing the error generated at the target pixel to the neighboring pixels included in the first frame based on the intra-frame error distribution rate and the intra-frame error distribution weight, and distributing the error generated at the target pixel to the target pixel included in the second frame and the neighboring pixels included in the second frame based on the inter-frame error distribution rate and the inter-frame error distribution weight.

An integrated circuit that diffuses an error generated at a target pixel when converting a first video signal having M tone levels to a second video signal having N tone levels by restricting the tone levels of the first video signal to the N tone levels, where N<M, and M and N are natural numbers, the integrated circuit comprising:

• a pixel variation information obtaining unit operable to obtain pixel variation information based on a degree of pixel value variation using pixel values in a predetermined area consisting of the target pixel included in a first frame that is formed using the first video signal and two or more neighboring pixels of the target pixel;
• a weight determination unit operable to determine, based on the pixel variation information, an intra-frame error distribution rate that is used to distribute the error generated at the target pixel within the first frame and an inter-frame error distribution rate that is used to distribute the error generated at the target pixel to a second frame different from the first frame, and determine, based on the intra-frame error distribution rate and the inter-frame error distribution rate, an intra-frame error distribution weight that is used to weight each of the neighboring pixels that are included in the first frame and an inter-frame error distribution weight that is used to weight a target pixel that is included in the second frame and is at a position identical to a position of the target pixel included in the first frame and neighboring pixels that are included in the second frame and are at positions identical to the neighboring pixels included in the first frame;
• and
• an error diffusion unit operable to distribute the error generated at the target pixel to the neighboring pixels included in the first frame based on the intra-frame error distribution rate and the intra-frame error distribution weight, and distribute the error generated at the target pixel to the target pixel included in the second frame and the neighboring pixels included in the second frame based on the inter-frame error distribution rate and the inter-frame error distribution weight.