Display system, image output device and image display device

An image data output device which outputs image data, comprising:

• an image pickup unit;
• an extraction unit which extracts an edge component of picked-up image data, and the extraction unit has a numeric representation unit which performs predetermined filter processing to a luminance component of each pixel constituting the picked-up image data and numerically represents the edge component of the picked-up image data;
• a compression rate setting unit which determines whether a picked-up image corresponding to the picked-up image data is a natural image or not and sets a compression rate for the picked-up image data in accordance with a type of the picked-up image corresponding to the picked-up image data;
• and
• an image data output unit which outputs a compressed image data acquired by compressing the picked-up image at the compression rate that is set.

An image data transmission method for transmitting image data from an image data output device to an image display device, the method comprising:

• in the image data output device,
• (a) extracting an edge component of the image data;
• (b) performing predetermined filter processing to a luminance component of each pixel constituting the image data and numerically representing the edge component of the image data;
• (c) determining whether an image corresponding to the image data is a natural image or not and setting a compression rate for the image data;
• (d) compressing the image data at the set compression rate;
• and
• (e) outputting the compressed image data compressed at the compression rate as the image data to the image display device.