Demosaic operation circuit, image sensing device and operation method of the same

An image sensing device, comprising:

• an image sensor including a pixel array having a plurality of pixels;
• an image signal processor suitable for processing an output signal of the image sensor;
• and
• a mosaic operation circuit,
• wherein the mosaic operation circuit comprises
• a white pixel value estimation circuit suitable for acquiring an RGB channel average value and a directional gradient value of a white pixel for each direction using source pixel data provided from a pixel array having a plurality of pixels, and estimating a white pixel value based on the RGB channel average value and the directional gradient value of the white pixel for each direction;
• a fine adjustment circuit suitable for finely adjusting an estimated white pixel value by removing a noise through a different filter based on weight values which are differently allocated according to a gradient of a center pixel and a neighboring white pixel;
• a chroma estimation circuit suitable for estimating a chroma for each channel by calculating a chroma array based on the source pixel data and a finely adjusted white pixel value;
• and
• a color correction circuit suitable for correcting a color based on the finely adjusted white pixel value and the chroma for each channel.

An operation method of an image sensing device, comprising:

• acquiring an RGB channel average value and a directional gradient value of a white pixel for each direction using source pixel data provided from a pixel array having a plurality of pixels, and estimating a white pixel value based on the RGB channel average value and the directional gradient value of the white pixel for each direction;
• finely adjusting an estimated white pixel value by removing a noise through a different filter based on weight values which are differently allocated according to a gradient of a center pixel and a neighboring white pixel;
• estimating a chroma for each channel by calculating a chroma array based on the source pixel data and a finely adjusted white pixel value;
• and
• correcting a color based on the finely adjusted white pixel value and the chroma for each channel.