Image processing method and apparatus using local brightness gain to enhance image quality

摘要

An image processing apparatus is provided. The image processing apparatus includes a local brightness adjustment circuit and an image enhancement circuit. The local brightness adjustment circuit is arranged to obtain a local brightness gain relation between an input image before a local brightness adjustment and the input image after the local brightness adjustment. The image enhancement circuit is coupled to the local brightness adjustment circuit, and is arranged to perform at least one of a noise reduction and an edge enhancement upon an image to be processed according to the local brightness gain relation to generate an output image.

主权项

1. An image processing method, comprising:
obtaining a local brightness gain relation between an input image before a local brightness adjustment and the input image after the local brightness adjustment; and performing at least one of a noise reduction and an edge enhancement upon an image to be processed according to the local brightness gain relation to generate an output image; wherein the local brightness adjustment comprises: for each image unit of the input image:
adjusting a brightness value of the image unit according to a pixel value of an image block including the image unit in the input image; wherein the image unit of the input image comprises at least one pixel; and the step of adjusting the brightness value of the image unit according to the pixel value of the image block including the image unit in the input image comprises: providing a plurality of curve functions; obtaining a specific curve function of the plurality of curve functions corresponding to the image unit according to an average pixel value of all pixel values of the image block; and adjusting the brightness value of the image unit according to the specific curve function; wherein the step of adjusting the brightness value of the image unit according to the specific curve function comprises: performing a curve index calculation upon the image unit according to the specific curve function, and accordingly obtaining a plurality of specific curve functions respectively corresponding to a plurality of pixels included in the image unit; and adjusting a plurality of brightness values of the pixels according to the specific curve functions, respectively.