Digital Pan Tilt Zoom Processor for Fisheye Distortion Correction
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Solution Overview
Problem
Camera viewing systems with mechanical pan, tilt, and zoom mechanisms are cumbersome, unreliable, and difficult to conceal or use in close quarters due to their mechanical nature, while electronic solutions using fisheye lenses produce distorted images that require real-time correction for wide-angle viewing.
Innovation Solution
A camera viewing system employing a Digital Pan Tilt Zoom (DPTZ) processor that performs real-time distortion correction on embedded processors, ASICs, or FPGAs to transform distorted wide-angle images into non-distorted, normal perspective images, equivalent to mechanical pan, tilt, and zoom functions, using inverse mapping and interpolation techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a mechanical pan-tilt platform with zoom lenses is used to achieve multiple camera orientations and image magnification, then the viewing system can provide flexible camera control, but the system becomes cumbersome, unreliable, and occupies significant volume
Solution Approach 1:
The patent replaces the mechanical pan-tilt platform with moving mechanisms with an electronic solution using a wide-angle lens (such as a fisheye lens) that captures a large sector of surrounding space all at one time. The mechanical orientation and zoom functions are substituted by capturing a wide field of view and electronically processing the image to provide pan, tilt, and zoom effects without any moving mechanical parts.
Solution Approach 2:
The patent creates an electronic copy of the mechanical pan-tilt-zoom functionality through software processing. By capturing the entire scene with a wide-angle lens and then selectively processing regions of the captured image, the system replicates the effect of mechanical camera orientation and magnification changes without requiring physical movement of camera components.
2Adaptability or versatility
If a wide-angle lens such as a fisheye lens is used to capture a large sector of surrounding space, then the horizontal and vertical viewing angle is widened, but the image becomes non-linear distorted
Solution Approach 1:
The patent applies parameter changes by transforming the distorted image coordinates through mathematical functions. The processing unit modifies the spatial parameters of the captured image by mapping distorted coordinates to corrected coordinates, thereby changing the geometric parameters to eliminate distortion while preserving the wide viewing angle capability.
Solution Approach 2:
The patent replaces optical correction mechanisms with electronic image processing. Instead of using complex optical systems to correct distortion at the hardware level, the system captures the distorted image and corrects it through digital processing, substituting mechanical/optical correction with computational methods.
3Volume of moving object
If real-time distortion correction is performed on embedded processors, ASICs, or FPGAs, then compact and concealable camera systems are achieved, but the processing complexity increases
Solution Approach 1:
The patent extracts the distortion correction functionality into a dedicated processing unit that can be implemented on embedded processors, ASICs, or FPGAs. By separating the correction function from the main camera system, the design achieves compact form factor while managing processing complexity through specialized hardware implementation.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing correction lookup tables that map distorted coordinates to corrected coordinates. This allows the real-time correction process to simply look up and apply pre-computed transformation values, significantly reducing the processing complexity during real-time operation while maintaining compact system volume.
Data Source
AI summary
A method and apparatus for image processing a lens-distorted image (e.g., a fisheye image) is provided. The method includes partitioning coordinate points in a selected output image into tiles. The output image is an undistorted rendition of a subset of the lens-distorted image. Coordinate points on a border of the tiles in the output image are selected. For each tile, coordinate points in the lens-distorted image corresponding to each selected coordinate point in the output image are calculated. In addition, for each tile, a bounding box on the lens-distorted image is selected. The bounding box includes the calculated coordinates in the lens-distorted image. The bounding boxes are expanded so that they encompass all coordinate points in the lens-distorted image that map to all coordinate points in their respective corresponding tiles. Output pixel values are generated for each tile from pixel values in their corresponding expanded bounding boxes.