Pixel Conversion Device and Pixel Conversion Method

A pixel conversion method which converts a first digital image signal in a format of 4:2:0 including a digital luminance signal and a digital color difference signal before conversion into a second digital image signal in a format of 4:4:4 including digital luminance signal and a digital color difference signal after conversion, comprising:

• detecting a histogram in the luminance signal block;
• detecting a luminance boundary in the luminance signal block on the basis of information on the extracted histogram,
• setting a color-difference boundary of the same pattern as that of the luminance boundary to a virtual color-difference signal block of the same data rate as that of the luminance signal block to divide the virtual color-difference signal block into each area, and to generate a control signal for unifying the same area by pixel data of the same value;
• and
• converting a color-difference signal block of the digital color-difference signal before conversion into the same data rate as that of the luminance signal block to correlate the converted color-difference signal block to the virtual color-difference signal block by means of a data rate conversion module, correcting resolution on the basis of the control signal from the picture characteristic extraction module, and obtaining a color-difference signal for the format of 4:4:4.

A pixel conversion method which converts a first digital image signal in a format of 4:2:0 including a digital luminance signal and a digital color difference signal before conversion into a second digital image signal in a format of 4:4:4 including digital luminance signal and a digital color difference signal after conversion, comprising:

• writing the digital luminance signal before conversion and the digital color-difference signal before conversion into first and second frame memories
• reading the digital luminance signal before conversion and the digital color-difference signal before conversion from the first and the second frame memories by means of an arithmetic processing module;
• extracting a histogram in a luminance signal block which is a processing module;
• detecting a luminance boundary in the luminance signal block on the basis of information on the extracted histogram;
• and
• converting a color-difference signal block of the digital color-difference signal before conversion into the same data rate as that of the luminance signal block to correlate, setting a color-difference boundary in the same pattern as that of the luminance boundary to divide the color-difference signal block into each area, correcting resolution by unifying the same area with pixel data of the same value, and obtaining a color-difference signal for the format of 4:4:4.