Ratio-Preserving Half-Cylindrical Warps for Natural Image Stitching

TL;DR

This paper introduces a ratio-preserving half-cylindrical warp for natural image stitching that combines homography and cylindrical warps with a pixel selection strategy to reduce distortion and improve visual quality.

Contribution

It proposes a novel warp method that preserves aspect ratios and reduces distortion by combining homography, cylindrical warps, and pixel sampling, differing from previous approaches.

Findings

Reduces projective distortion in stitched images

Produces more natural-looking stitched results

Efficiently combines warping techniques for better quality

Abstract

A novel warp for natural image stitching is proposed that utilizes the property of cylindrical warp and a horizontal pixel selection strategy. The proposed ratio-preserving half-cylindrical warp is a combination of homography and cylindrical warps which guarantees alignment by homography and possesses less projective distortion by cylindrical warp. Unlike previous approaches applying cylindrical warp before homography, we use partition lines to divide the image into different parts and apply homography in the overlapping region while a composition of homography and cylindrical warps in the non-overlapping region. The pixel selection strategy then samples the points in horizontal and reconstructs the image via interpolation to further reduce horizontal distortion by maintaining the ratio as similarity. With applying half-cylindrical warp and horizontal pixel selection, the projective distortion in vertical and horizontal is mitigated simultaneously. Experiments show that our warp is efficient and produces a more natural-looking stitched result than previous methods.