Lens Shading Compensation Apparatus and Method, and Image Processor Using the Same

An image processor of an image apparatus compensating a lens shading phenomenon—wherein the image apparatus comprises a sensor unit, the image processor and a display unit—, the image processor comprising:

• an interpolation part that color interpolates a digital image signal inputted from the sensor unit so that all the pixels of a pixel array each has red, green and blue components;
• a lens shading compensation part that analyzes luminance information on red, green and blue colors of all the pixels of the pixel array, which are color interpolated by the interpolation part, according to color, measures the luminance of a portion having a predetermined size and positioned around a first central pixel of the pixel array, sets the luminance of the portion as an auto exposure value,
• detects a second central pixel in a lens shading image corresponding to the luminance information, partitions pixels in units of block according to the distance from the second central pixel, generates a compensation value per block corresponding to the auto exposure value, saves the compensation value per block as a compensation table,
• calculates a distance between an object pixel and the second central pixel, computes a compensation value for an object pixel by using the compensation value per block corresponding to the distance between an object pixel and the second central pixel, thereby producing a shading mask image for each color, and generates and outputs pixel compensation information by combining the shading mask image with the luminance information;
• and
• a subsequent processing part processing the pixel compensation information to be displayed through the display unit.

A method for compensating a lens shading phenomenon in an image sensor, the method comprising:

• (a) generating luminance information from primitive image data that has been color interpolated so that each pixel has red, green and blue color components, for each color;
• (b) measuring an average luminance of a portion having a predetermined size and positioned around a first central pixel of the pixel array through the luminance information and setting the average luminance of the portion as an auto exposure value;
• (c) detecting a second central pixel from a lens shading image corresponding to the luminance information;
• (d) partitioning pixels in units of block according to the distance from the second central pixel, generating and saving a compensation value per block corresponding to the auto exposure value;
• (e) calculating a distance between an object pixel and the second central pixel;
• (f) producing a compensation value for the object pixel by using the compensation value per block corresponding to the distance between the object pixel and the second central pixel, and creating a shading mask image for each color;
• and
• (g) generating pixel compensation information by combining the primitive image data with the shading mask image and outputting the compensation pixel information.