Method and apparatus providing color interpolation in color filter arrays using edge detection and correction terms

An imager comprising:

• a plurality of image pixel sensors that produce sensed values of a first color, a second color and a third color;
• interpolation means for using the sensed values of the first color to determine a first set of pixel values for a plurality of image pixels in a pixel kernel, including a target pixel and pixels surrounding the target pixel, for the first color, determining at least three edge direction values using the first set of pixel values, the three edge direction values respectively represent a horizontal edge direction, a vertical edge direction and a diagonal edge direction, determining an edge direction of the target pixel based on the edge direction values, determining whether the target pixel is at an edge of an image based on difference values calculated using the sensed values of pairs of same colored image pixels in the pixel kernel, wherein it is determined that the target pixel is at an edge if the maximum difference value is greater than a threshold value, and calculating interpolation values for the first, second and third colors of the target pixel based on the sensed values for the respective color of the image pixels in the pixel kernel and the edge direction;
• and
• means for creating a representative image using the calculated interpolated values of the first, second and third colors.

An image processing apparatus comprising:

• an image sensing unit for obtaining an image and outputting sensed values corresponding to light applied to the image, each sensed value corresponding to a color of a color pattern;
• and
• an image processor for interpolating a value for each color of the color pattern for each of a plurality of pixels of the image, the image processor performing the steps of:
• determining pixel values of one color of the color pattern for each pixel in a kernel of pixels surrounding a target pixel using the sensed values corresponding to the one color for the respective pixels in the kernel;
• determining at least three edge direction values based on the determined pixel values of the one color for the pixels in the kernel, the three edge direction values respectively represent a horizontal edge direction, a vertical edge direction and a diagonal edge direction;
• recalculating the pixel value of the one color of the target pixel based on the pixel values of the one color of pixels in the kernel if the edge direction is determined to be horizontal or vertical;
• determining whether the target pixel is at an edge within an image based on difference values calculated using the sensed values of pairs of same colored pixels in the kernel of pixels, wherein it is determined that the target pixel is at an edge if the maximum difference value is greater than a threshold value;
• and
• determining the interpolated values for each color of the color pattern for the target pixel based on the sensed values corresponding to the respective color for the pixels in the kernel, whether the target pixel is at the edge and the edge direction.

A method carried out by an image processing apparatus, comprising:

• determining pixel values of one color of a color pattern for each pixel in a kernel of pixels surrounding a target pixel using sensed values corresponding to the one color for the respective pixels in the kernel;
• determining at least three edge direction values based on the determined pixel values of the one color for the pixels in the kernel, the three edge direction values respectively represent a horizontal edge direction, a vertical edge direction and a diagonal edge direction;
• recalculating the pixel value of the one color of the target pixel based on the pixel values of the one color of pixels in the kernel if the edge direction is determined to be horizontal or vertical;
• determining whether the target pixel is at an edge within an image based on difference values calculated using sensed values of pairs of same colored pixels in the kernel of pixels, wherein it is determined that the target pixel is at an edge if the maximum difference value is greater than a threshold value;
• and
• determining an interpolated value for the target pixel for each color of said color pattern based on the sensed values corresponding to the respective color for the pixels in the kernel, whether the target pixel is at the edge and the edge direction.