Understanding Overlap and Constraints in Stereo Fisheye Image Pairs

This statement refers to the requirements for a pair of stereo fisheye images to achieve accurate 3D reconstruction. It means that the images must have an overlap of more than 80% and must satisfy the 'main optical axis and epipolar line orthogonality-transverse axis co-linear constraints'.

Let's break down the terminology:

• Stereo Fisheye Image Pair: Two images captured by fisheye lenses from different viewpoints. Fisheye lenses have a wide field of view, which is advantageous for capturing a larger scene.
• Overlap: The percentage of the scene that is captured by both images in the pair. High overlap ensures more accurate depth information.
• Main Optical Axis: The imaginary line passing through the center of the lens and perpendicular to the image plane.
• Epipolar Line: A line in one image corresponding to the set of possible locations of a point in the other image. Epipolar lines are formed due to the different viewpoints of the stereo cameras.
• Orthogonality: The condition where the main optical axis of each camera is perpendicular to the epipolar line.
• Transverse Axis: An axis perpendicular to the main optical axis and the epipolar line.
• Co-linear: The condition where the transverse axes of the two cameras are aligned along a single line.

These constraints ensure that the epipolar geometry of the stereo pair is well-defined and consistent, which is essential for accurate 3D reconstruction algorithms to work correctly. By satisfying these requirements, the images provide the necessary information for calculating the 3D position of points in the scene.