Active mask for electronic imaging system

• US 20080007645A1
• Filed: 02/27/2007
• Published: 01/10/2008
• Est. Priority Date: 07/07/2006
• Status: Active Grant

• Current Assignee: Immersive Licensing, Inc.
• Original Assignee: Immersive Ventures Inc. (Digital Domain Holdings Ltd.)
• Inventors: McCutchen, David
• Granted Patent: US 7,973,838 B2
• Time in Patent Office: Days
• US Class Current: 348/360
• CPC Class Codes: H04N 23/75 by influencing optical camera components

Abstract

An active pixel masking system for automatic glare suppression uses a variably transmissive screen such as an LCD in front of a lens. A measurement by an image sensor of oversaturated pixels from one or more extremely bright lights is used to generate corresponding opaque pixels in the variably transmissive screen, thereby preventing the excess light from entering the lens, and thereby clarifying the appearance of any objects near to the bright light. A continuous reading of a motion picture image is used to move the location and area of the opaque pixels in response to the motion and area of the light.

Claims

1. An active filter method, comprising the steps of:

transmitting the light representing the components of a field of view successively through a variably transmissive screen, a lens and finally into an associated image sensor, with pixel divisions on the image sensor corresponding to pixel divisions on the variably transmissive screen,

accumulating electrical charges for each of the pixel divisions of the image sensor as a result of said light representing the components of a field of view for the time span of a given frame period,

identifying those pixel locations whose electrical charges exceed a given level, representing excess light producing oversaturated pixels,

masking those pixel divisions of the variably transmissive screen which correspond to the identified oversaturated pixels with a masking signal, thereby blocking the transmission of light into the lens at those particular locations in the field of view, preventing the subsequent oversaturation of those pixels on the image sensor due to an excess of light and improving the appearance of the image produced by the image sensor,

reading out the electrical charges of the image sensor to produce a final image.

2. The active filter method of claim 1, wherein the image sensor is repeatedly read out in frame periods, and the measurement of said oversaturated pixels in said storage processor during each frame period is used to generate the opacity signal to be sent to the variably transmissive screen during the subsequent frame period.

3. The active filter method of claim 2 wherein analysis of one or more groups of oversaturated pixels is performed to identify the overall shape of each group, wherein said overall shape is assumed to remain roughly the same over successive frame periods, and any additional oversaturated pixels detected along one border of said overall shape will generate a corresponding masking signal for said additional oversaturated pixels, but also a clearing of the masking signal for the pixels along the opposite border of said overall shape relative to said additional oversaturated pixels, thereby maintaining said shape of said group of oversaturated pixels, and moving said shape follow one or more moving lights over successive time periods.

4. The active filter method of claim 2 wherein variable degrees of opacity are produced in the pixels divisions of the variably transmissive screen by the opacity signal to improve the anti-alias characteristics of the masking of oversaturated pixels.

5. The apparatus of claim 1 wherein the variably transmissive screen is a liquid crystal display.

6. An active filter apparatus, comprising:

a lens allowing for the passage of light associated with a field of view, and

an image sensor coupled to said lens, said image sensor having a plurality of pixel divisions, wherein the light associated with the field of view is a converted into pixel values, each pixel value representing the light intensity of a particular portion of the field of view during a given frame period, and

a variably transmissive screen located in front of said lens, said variably transmissive screen being also having pixel divisions which correspond to the pixel divisions of the image sensor, said variably transmissive screen being wholly transmissive during the first frame period, and

a storage processor for said pixel values from the image sensor during a first frame period, including the location of each pixel value within the field of view, and the identification of the oversaturated pixels, which are those pixel divisions whose pixel values exceed a given oversaturation threshold, due to an excess of light entering the lens at that location in the field of view, and

a masking processor which sends an opacity signal during the second frame period to opaque the pixel divisions in the variable transmissive screen which correspond to the oversaturated pixels, thereby blocking the passage of light into the lens at those locations in the field of view, preventing the oversaturation of those pixels on the image sensor due to an excess of light and improving the appearance of the image produced by the image sensor during the second frame period.

7. The active filter apparatus of claim 6, wherein a motion picture is produced by repeated readout of the image sensor in frame periods, and the measurement of said oversaturated pixels in said storage processor during each frame period is used to generate the opacity signal to be sent to the variably transmissive screen during the subsequent frame period.

8. The apparatus of claim 7 wherein the overall shape of a group of oversaturated pixels is assumed to remain essentially the same over successive frame periods, and if oversaturated pixels are detected along one border of this shape, the opacity signal covers these up in the subsequent frame period, but also clears the pixels along the opposite border so as to maintain this shape, thereby enabling the masking processor to follow one or more moving lights.

9. The apparatus of claim 7 wherein variable degrees of opacity are produced in the pixels divisions of the variably transmissive screen by the opacity signal to improve the anti-alias characteristics of the masking of oversaturated pixels.

10. The apparatus of claim 6 wherein the variably transmissive screen is a liquid crystal display.

11. The apparatus of claim 6 wherein the variably transmissive screen transmits light by reflection.