How should the
Manually click onto the 4 corners in clockwise order to start the perspective correction
Click inside the inner white area of the marker to start the perspective correction
not implemented yet: Automatic marker detection: Click anywhere in the image to start the perspective correction
DPI of output image:
Inner Width of marker in mm:
Inner Height of marker in mm:
How should the perspective correction be done? (Multiple output paths can be selected for comparison)
command line (recommended for larger DPI)
How does it work? Show me the guts!
Show Sobel Gradient Image
Show Mask Image used for clipping
Show Clipped Gradient Image
Show Clipped Sobel Gradient Image with vectorized lines
This is just a testing ground for some ideas I want to try out...
The basic idea is this: You attach a printed marker (a black rectangle, I use
The perspective and scaling is derived from the vectorized inner contour of the black frame of the marker. The lines are vectorized with an antialiased search in the radon transformed gradient image (I always wanted to write this sentence:). Adjust the DPI of the output image to get more detail but be aware that the resulting image might be huge.
is used for solving the 8-dimensional linear equation that appears in the perspective matrix calculations...and thanks to clifford also for writing
...my perspective correction code is just a 1:1 translation of clifford's code to js (so this makes this webpage GPL I guess:). Thanks to bernhard for showing me the radon transform in the context of line vectorization :)
The latest version of the full source code can be found here:
questions, ideas, comments to:
I collect pictures of applications of the SurfaceAugmenter in
this flickr set.
Change the Input Image:
Result Images will be created here.