Is there a GDAL function similar to OpenCV's WarpPerspective?

Question

I't trying to mosaic a GeoTiff raster against another. Initially, they were both georeferenced in WGS-84 CRS. Using OpenCV, I calculated a homography transformation (a 3x3 projection matrix), that transforms an image to fit the other - I did it using rasters converted to JPEG images. Then, using OpenCV function warpPerspective, I applied my homography to the image and obtained a JPEG mosaic.

Now, I want to apply that transformation matrix to the GeoTiff raster and warp it along with it's geospatial information. However, I can't find an GDAL/osgeo function that would do that: gdal.Warp() seems to be doing something else entirely.

So, my question is: is there a function in GDAL that would accept my raster image and my transformation matrix and output the correctly transformed raster with modified geospatial information?

If not, is there a possible workaround to achieve that?

Answer 1

This solution requires using OpenCV 4.x and GDAL in python

You may want to try an affine transform between two images. cv.estimateAffine2D which gives you a 2x3 matrix

Get the transform of the pixel x,y coordinates of the second image to the first

warpedx = A[0,0]*x + A[0,1]*y + A[0,2]
warpedy = A[1,0]*x + A[1,1]*y + A[1,2] 

next you can validate by getting the those pixel coordinates and check if they match the original images pixel coorindates

xoff, a, b, yoff, d, e = ds.GetGeoTransform()
xp = a * x + b * y + xoff
yp = d * x + e * y + yoff

if the two points now match, go ahead and align the images and write the image with an updated geotransform