Patent ID: 6927793
Filing Date: 2005-08-09
Classification: H04N

Abstract:
1. A method for forming an image by means of an image sensor with an active area containing a plurality of pixels, comprising the steps of: (a) in two interrogation runs performed on a first subset of pixels, resetting the first subset of pixels, exposing the first subset of pixels and reading out the output value(s) of the first subset of pixels, wherein in said two interrogation runs, a longer exposure and a shorter exposure are performed; (b) combining said output values into a first combined output value by means of a merging function which is truly monotonic, continuous and continuously differentiable in all said output values, wherein said merging function has the following properties: (i) preference is given to the output value obtained from the longer exposure when said output values or a combination of said output values lie beneath a given lower limit; (ii) preference is given to the output value obtained from the shorter exposure when said output values or a combination of said output values lie above a given upper limit; (iii) said merging function increases truly monotonically in said output values when said output values lie between said lower limit and said upper limit; and (c) repeating steps (a) and (b) for at least one second subset of pixels.