Interlaced Video Motion Compensation via Field Shifting
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Solution Overview
Problem
Video surveillance cameras using interlaced displays suffer from image blurring when panned or tilted, resulting in a ghost-like appearance, especially in static scenes, due to capturing only half of the lines from each frame, which degrades video quality and reduces compression efficiency.
Innovation Solution
A method and apparatus that compensate for camera motion by capturing and shifting the relationship between interlaced video fields based on the camera's speed, using a shift register, controller, and detector to delay fields, improving image quality and compression efficiency during panning or tilting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an interlaced camera is used to save video bandwidth and provide smooth pictures, then video bandwidth is reduced and picture smoothness is improved, but image blurring and ghost-like appearance occur when the camera is panned or tilted
Solution Approach 1:
The system performs preliminary action by detecting camera motion and pre-shifting one of the video fields before combining them into a complete frame. This anticipatory adjustment prevents the ghost-like blurring effect that would otherwise occur during camera panning or tilting, allowing the use of interlaced scanning without quality degradation.
2Productivity
If the camera captures only half of the lines from each frame to save bandwidth, then video bandwidth consumption is reduced, but image quality deteriorates when the camera is moving
Solution Approach 1:
The shift register acts as an intermediary device that temporarily holds and shifts one of the video fields by a predetermined number of positions. This intermediary mechanism allows the system to maintain the bandwidth efficiency of interlaced scanning while compensating for camera motion, thereby preserving video quality during movement.
3Manufacturing precision
If motion compensation is applied to minimize blurring during camera movement, then image quality is improved, but device complexity increases due to additional components
Solution Approach 1:
The system changes the parameter of field positioning by shifting one video field by a predetermined number of positions based on detected camera motion. This parameter adjustment approach provides motion compensation with relatively simple circuitry, avoiding the need for complex real-time image processing while effectively reducing blurring during camera movement.
Data Source
AI summary
A method of compensating for the movement of a video surveillance camera comprising the steps of moving an interlaced camera, capturing a first video field of a frame at a first point in time, capturing a second video field of a frame at a second point in time, determining the speed at which the camera is moving, and shifting the relationship between the first and second video fields based on the period of time between the first point in time and the second point in time and the speed at which the camera is moving.