GNU Astronomy Utilities

6.4 Warp

Image warping is the process of mapping the pixels of one image onto a new pixel grid. This process is sometimes known as transformation, however following the discussion of Heckbert 1989179 we will not be using that term because it can be confused with only pixel value or flux transformations. Here we specifically mean the pixel grid transformation which is better conveyed with ‘warp’.

Image warping is a very important step in astronomy, both in observational data analysis and in simulating modeled images. In modeling, warping an image is necessary when we want to apply grid transformations to the initial models, for example, in simulating gravitational lensing. Observational reasons for warping an image are listed below:



Paul S. Heckbert. 1989. Fundamentals of Texture mapping and Image Warping, Master’s thesis at University of California, Berkeley.


All astronomical targets are blurred with the PSF, see Point spread function, however a cosmic ray is not and so it is very sharp (it suddenly stops at one pixel).