Patent ID: 7973838
Filing Date: 2011-07-05
Classification: H04N

Abstract:
1. A method for actively filtering a light image in a motion-picture camera comprising: transmitting light representing components of a field of view successively through a variably transmissive screen having a first grid of addressable pixels formed thereon, a lens and finally into an associated image sensor having a second grid of pixels formed thereon, with the light transmitted to each of at least some of the pixels on the image sensor also passing through a generally corresponding pixel on the variably transmissive screen; accumulating electrical charges for each of the pixels of the image sensor as a result of said light representing the components of the field of view for a time span of a given frame period; identifying a location of a first pixel on the image sensor whose electrical charge exceeds a given level, representing excess light producing at least one overexposed pixel; addressing a first pixel in the first grid that corresponds in location to the identified location of the first overexposed pixel; masking the addressed pixel starting at a first time of the given frame period, thereby at least partially blocking the transmission of light into the lens and reducing the exposure of the at least one overexposed pixel; addressing a second pixel in the first grid; masking the second pixel starting at a second time of the given frame period; a reading out electrical charges for at least some of the pixels on the image sensor to produce a final image; and analyzing one or more groups of overexposed pixels to identify an overall shape of each group of overexposed pixels, wherein said overall shape remains roughly the same over successive frame periods, and any additional overexposed pixels detected along one border of said overall shape generate a corresponding masking signal for said additional overexposed pixels and a clearing of the masking signal for the pixels along an opposite border of said overall shape relative to said additional overexposed pixels, thereby maintaining said shape of said group of overexposed pixels, and moving said overall shape to follow one or more moving lights over successive frame periods.