Dynamic range compression

A method of dynamic range compression of image data, the method comprising the steps of:

• down-sampling a frame of image data comprising a first array of pixels to generate a second array of pixels;
• applying a first median filter to the second array of pixels to generate a blurred array of pixels;
• up-sampling the blurred array of pixels;
• and
• removing at least a portion of low-frequency gradient data generated by previous steps from the frame of image data.

An apparatus for dynamic range compression of image data, comprising:

• a processor unit coupled to an image-data source, the processor unit being configured to:
• down-sample a frame of image data comprising a first array of pixels to generate a second array of pixels;
• apply a first median filter to the second array of pixels to generate a blurred array of pixels;
• up-sample the blurred array of pixels;
• and
• remove at least a portion of low-frequency gradient data thereby generated by the processor unit from the frame of image data.

An apparatus for approximating a gaussian-blur filter, comprising:

• a processor unit coupled to an data source, the processor unit being configured to:
• apply a first box filter having a first kernel size to a group of pixels of a frame of data;
• and
• apply a second box filter having a second kernel size to the group of pixels, wherein first kernel coefficients of the first box filter and second kernel coefficients of the second box filter are configured to approximate a resultant gaussian function.