1. A method for determining a background color at a pixel of interest in a digital image, said method comprising: in an image-processing system, determining a pixel of interest in a digital image, wherein said pixel of interest is part of a first scan line with an associated first scan direction in said digital image; in said image-processing system, receiving a color value for said pixel of interest; in said image-processing system, receiving a control signal associated with said pixel of interest; in said image-processing system, receiving a first background color estimate, wherein said first background color estimate is associated with said first scan line; in said image-processing system, receiving a previous background color estimate, wherein said previous background color estimate is associated with a previous scan line in said digital image; in said image-processing system, calculating a first color difference between said color value for said pixel of interest and said first background color estimate; in said image-processing system, calculating a second color difference between said color value for said pixel of interest and said previous background color estimate; and in said image-processing system, determining a first-scan background color estimate for said pixel of interest based on said control signal, said first color difference and said second color difference.