why do I get a strange result with griddata cubic?
8 次查看(过去 30 天)
显示 更早的评论
Hi! I used the griddata cubic interpolation for the values of an image. I get this image that has a much higher range, from -300 to 400 aproximately. The non processed image has a range from 90 to 130. Any ideas why this happens?Thanks!
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/695794/image.png)
3 个评论
Matt J
2021-7-27
The code you've posted does not run, I'm afraid:
Unrecognized function or variable 'x'.
Error in test (line 12)
vq_4 = griddata(x,y,C,xq,yq,'cubic');
采纳的回答
Walter Roberson
2021-7-27
This is expected behavior when there are sharp edges, especially with a surrounding flat area.
B--
|
-A-
Especially if the region near B is dense, but the edge itself is sparse, then the polynomial generated near the edge needs to mathematically dip down below the base in order to gain the necessary steepness to match the flat control points to the left together with the high points to the right. Polynomials cannot just suddenly rise steeply without a leading edge, so the math needs to insert a downward edge to be able to rise from.
9 个评论
Bruno Luong
2021-7-30
working with xs/ys instead of x/y
xs = sx*x
ys = sy*y
sx, sy are appropriate scaling factors that you have to figure it out.
更多回答(0 个)
另请参阅
产品
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!