Camera Extrinsic Parameter Calibration for Panoramic Image Stitching
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Solution Overview
Problem
Current panoramic image stitching technologies are limited in handling camera rotations in both horizontal and vertical directions, leading to inaccuracies in extrinsic parameter calibration, which affects the quality of stitched panoramic images.
Innovation Solution
A method for calibrating extrinsic parameters of a camera that involves acquiring multiple images with varying rotation angles, matching feature points across images, and calibrating the extrinsic parameters using a first difference representation between coordinate representations of matched feature points in a reference coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If recorded pose is directly used for image stitching, then the process is simple, but the stitching accuracy deteriorates due to large errors in recorded pose
Solution Approach 1:
The patent performs extrinsic parameter calibration before image stitching to correct pose errors. By pre-calibrating the camera parameters using feature point matching and coordinate transformation, the system prepares accurate transformation relationships in advance, ensuring both stitching accuracy and process efficiency.
2Measurement precision
If feature point matching is performed among multiple images, then extrinsic parameter calibration accuracy is improved, but the computational complexity increases
Solution Approach 1:
The patent segments the calibration process into distinct modules: feature point extraction, feature point matching between image pairs, coordinate representation transformation, and extrinsic parameter calculation. This modular segmentation reduces computational complexity by organizing the complex matching process into manageable, independent steps that can be processed efficiently.
3Adaptability or versatility
If camera rotates in both horizontal and vertical directions, then panoramic coverage is improved, but extrinsic parameter calibration accuracy deteriorates due to complex rotation movements
Solution Approach 1:
The patent extends the calibration approach from traditional single-dimensional (horizontal) rotation to two-dimensional (horizontal and vertical) rotation. By incorporating vertical rotation angles into the extrinsic parameter model and using three-dimensional coordinate transformation, the system accurately calibrates cameras performing complex multi-directional movements, enabling comprehensive panoramic coverage while maintaining calibration accuracy.
Data Source
AI summary
The invention provides a camera extrinsic parameter calibration method, an image stitching method and an apparatus thereof. The calibration method can include: acquiring a plurality of images captured by the camera based on a plurality of sets of extrinsic parameters to be calibrated, wherein each of the plurality of sets of extrinsic parameters to be calibrated include a horizontal rotation angle and a vertical rotation angle; obtaining at least one matched image pair based on feature point matching among the plurality of images, wherein each matched image pair includes matched feature point pairs with a quantity satisfying a threshold condition; and calibrating the plurality of sets of extrinsic parameters to be calibrated according to a first difference representation between coordinate representations of each matched feature point pair of each matched image pair in a reference coordinate system.