Minimising algorithm‐induced artefacts in true ortho‐image generation: a direct method implemented in the vector domain

True ortho‐images are generated from perspective images with both object and terrain displacement distortion corrected and with occlusions removed. However, widely used algorithms based on a Z‐buffer have drawbacks and may result in artefacts in the generated ortho‐images. This paper analyses the artefacts induced by Z‐buffer algorithms in true ortho‐image generation, and proposes a vector‐based method to avoid algorithm‐induced artefacts. The proposed method treats a perspective image pixel as a square patch instead of an image pixel point, and generates ortho‐images in the vector domain. Under the vector implementation, occlusion detection is a simple process, and image resampling becomes a straightforward procedure. Most importantly, this method can minimise artefacts in the ortho‐images so generated.