Ticket #2327 (closed defect: fixed)
cubicspline resampling and other resamplers don't work for the entire image
|Reported by:||sprice||Owned by:||dron|
|Severity:||normal||Keywords:||warper cubicspline cubic bilinear near|
If I resample a large image (14400x14400px) using cubicspline to be much smaller (1024x1024px), the cubic spline resampling seems to miss some 'strips' of the image. These 'strips' end up looking like nearest neighbor sampling is being used, and look similar to static in my raster set. The strips appear at regular intervals inside the image, and along the edges. This problem does not appear when using cubic interpolation.
These problem 'strips' become quite obvious when using a ZonePlate? test image (and ImageMagick?): http://www.worldserver.com/turk/opensource/#ZonePlate
I generated my test image using these commands: ./ZonePlate -w 14400 -h 14400 -s 1 -o z14400.gray convert -size 14400x14400 gray:z14400.gray PNG42:z14400.png
Here is the warp command: gdalwarp -r cubicspline -ts 1024 1024 z14400.tif z14400.cs.tif
Attached is the output I get. The input is simply concentric rings of varying frequency. The output should be mostly gray, but instead has strips of black & white running through it.