Method and apparatus for detecting changes in a video display

A system for recording a scene when a change has occurred in the scene, comprising:

• a display device for converting said scene into a plurality of sequentially generated pixels to represent a frame of pixels at a given time, and said display device operable to generate a plurality of sequential frames, each of said pixels having a video value representing the relative intensity of said pixel in said associated frame;
• an accumulator for generating a single value for each of said frames, said single value for a given one of said frames representing the average intensity of substantially all of said pixels associated with said given frame, said accumulator operating on said pixels in said given frame as they are sequentially generated such that said video values for all of said pixels in said given frame are not stored,
• a memory for storing said single value for select ones of said frames;
• an averaging circuit for averaging each of said stored single values with said single values for a predetermined number of adjacent frames and generating a single accumulated frame value for the frame associated with said each stored single value for storage in said memory;
• a comparison circuit for comparing select ones of said stored single accumulated frame values that are associated with different frames that are not adjacent to each other and outputting a scene change alarm if the comparison of said select single accumulated frame values meets user defined comparison criteria;
• and
• a recording device for being activated by said scene change alarm and recording the scene output by said display device.

A method for monitoring a given scene, comprising the steps of:

• converting the scene into a plurality of sequentially generated pixels to represent a frame of pixels at a given time as a given frame, and the step of converting operable to generate a plurality of sequential frames, each of the pixels in each of the frames having a video value representing the relative intensity of the pixel in the associated frame;
• generating a single value for each of the frames, the single value for the given frame representing the average intensity of substantially all of the associated pixels, the step of generating operating on the pixels in the given frame as they are sequentially generated such that the video values for all of the pixels in the given frame are not stored;
• storing in a memory the single value for select ones of the frames;
• averaging each of the stored single values with the single values for a predetermined number of adjacent frames and generating a single accumulated frame value for the frame associated with said each stored single value for storage in the memory;
• and
• comparing select ones of the stored single accumulated frame values that are associated with different frames that are not adjacent to each other and outputting a scene change alarm if the comparison of the select single accumulated frame values meets user defined comparison criteria.

A method for recording a scene where a change has occurred in the scene, comprising the steps of:

• converting the scene into a plurality of sequentially generated pixels to represent a frame of pixels at a given time as a given frame, and the display device operable to generate a plurality of sequential frames, each of the pixels having a video value representing the relative intensity of the pixel in the frame;
• generating a single value for each of the frames, the single value for each of the frames representing the average intensity of substantially all of the associated pixels, the step of generating operating on the pixels in the given frame as they are sequentially generated such that the video values for all of the pixels in the given frame are not stored;
• storing in a memory said single values for select ones of said frames;
• averaging each of the stored single values with the single values for a predetermined number of adjacent frames and generating a single accumulated frame value for the frame associated with said each stored single value for storage in the memory;
• comparing select ones of the stored single accumulated frame values that are associated with different frames that are not adjacent to each other and outputting a scene change alarm if the comparison of the select single accumulated frame values meets predetermined comparison criteria;
• and
• activating a recording device in response to the generation of the scene change alarm to record the scene.