Patent ID: 9087383
Filing Date: 2015-07-21
Classification: G06T,H04N

Abstract:
1. A method for reducing a background in a raster image, the raster image comprising pixels having a lightness value, the background indicating a deviation between a lightness value of a subset of pixels in the raster image and a maximum lightness value of raster image input values, the method comprising the steps of: selecting a target pixel in the raster image; determining a first average lightness value for a first number of pixels around the target pixel; determining a second average lightness value for a second number of pixels around the target pixel; selecting a minimum of the first and second average lightness values as a background parameter; scaling the lightness value of the target pixel using said background parameter to the maximum lightness value of a predetermined output range, thereby obtaining a scaled lightness value of the target pixel; and generating an output raster image using the scaled lightness value of the target pixel, wherein said first number of pixels around the target pixel is substantially smaller than said second number of pixels around the target pixel.