Offset Fisheye Sensor Alignment for Surveillance Coverage
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Solution Overview
Problem
Wide angle or fisheye security cameras often capture significant portions of uninteresting areas, such as sky or ceilings, which reduce their surveillance value and suffer from varying optical resolution due to image distortion, leading to inefficient use of the camera's field of view.
Innovation Solution
The camera's image sensor is offset relative to the lens system, allowing for adjustments during manufacturing or installation to better align the camera's 'sweet spot' with areas of interest, reducing uninteresting regions and optimizing image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a wide angle or fisheye lens is used to capture a wide field of view, then the surveillance coverage area is improved, but the optical resolution varies across the image and uninteresting areas (sky, ceilings) occupy significant portions
Solution Approach 1:
The patent applies asymmetry by offsetting the image sensor from the optical axis of the lens system. Instead of symmetric alignment where the sensor center coincides with the optical axis, the sensor is deliberately positioned at an offset distance, creating an asymmetric configuration that shifts the effective field of view away from the center toward areas of interest, thereby improving the distribution of optical resolution across meaningful surveillance areas.
Solution Approach 2:
The patent implements local quality by optimizing the optical resolution specifically for areas of interest through sensor offset. Rather than uniform resolution distribution across the entire wide field of view, the offset positioning concentrates higher optical resolution on relevant surveillance zones while accepting reduced resolution in less important areas, thereby improving the effective quality of captured images in critical regions.
2Reliability
If the image sensor is centered on the optical axis, then the lens system operates at its optimal design point, but uninteresting areas such as sky or ceilings occupy significant portions of the captured image
Solution Approach 1:
The patent deliberately introduces asymmetry by offsetting the image sensor from the optical axis. This asymmetric positioning allows the camera to capture more interesting areas (ground level, doorways, windows) while reducing the proportion of uninteresting areas (sky, ceilings), thereby improving surveillance effectiveness without completely compromising lens system performance through controlled deviation from the centered configuration.
3Adaptability or versatility
If the camera is mounted in wall mode or ceiling mode orientation, then the installation flexibility is improved, but uninteresting portions (sky, ceilings) are captured which reduce surveillance value
Solution Approach 1:
The patent uses asymmetric sensor offset to compensate for the inherent limitations of standard mounting orientations. By offsetting the sensor from the optical axis, the system can maintain versatile mounting options (wall mode, ceiling mode) while adjusting the effective field of view to capture more interesting areas and less uninteresting areas, thereby improving surveillance value without sacrificing installation flexibility.
Data Source
AI summary
A wide angle, e.g., fisheye, surveillance, e.g., security, camera comprises an offsetting mechanism for offsetting a center of the image sensor relative to an optical axis of the fisheye lens system. Often when fisheye cameras are wall mounted a substantial area of the image may be dedicated to looking at sky or ceiling. A similar situation can arise when a fisheye camera is ceiling mounted next to a wall or other structure. Portions of the image will be unchanging and of little value for surveillance. The camera provides the capability to offset the lens system relative to the image sensor. In examples, this offset is performed as a factory manufacture or calibration step. In other examples, the offset is performed as an adjustment in the field at the time of installation or thereafter.