The reason you have holes in your image is because you are computing the location in imagerot of each pixel in imagepad. You need to do the computation the other way around. That is, for each pixel in imagerot interpolate in imagepad. To do this, you just need to apply the inverse transform, which in … Read more
Disclaimer: I’m mostly writing this post with syntactical considerations and general behaviour in mind. I’m not familiar with the memory and CPU aspect of the methods described, and I aim this answer at those who have reasonably small sets of data, such that the quality of the interpolation can be the main aspect to consider. … Read more
Lets define first a simple helper function in order to make it more straightforward to handle indices and logical indices of NaNs: import numpy as np def nan_helper(y): “””Helper to handle indices and logical indices of NaNs. Input: – y, 1d numpy array with possible NaNs Output: – nans, logical indices of NaNs – index, … Read more
changed 20 Oct: this class Invdisttree combines inverse-distance weighting and scipy.spatial.KDTree. Forget the original brute-force answer; this is imho the method of choice for scattered-data interpolation. “”” invdisttree.py: inverse-distance-weighted interpolation using KDTree fast, solid, local “”” from __future__ import division import numpy as np from scipy.spatial import cKDTree as KDTree # http://docs.scipy.org/doc/scipy/reference/spatial.html __date__ = “2010-11-09 … Read more
An easy solution, as you mentioned, is to simply connect the points with a straight line. Here’s the code to do so: public void onDraw(Canvas canvas) { Path path = new Path(); boolean first = true; for(Point point : points){ if(first){ first = false; path.moveTo(point.x, point.y); } else{ path.lineTo(point.x, point.y); } } canvas.drawPath(path, paint); } … Read more
Cause Some images are just very hard to down-sample and interpolate such as this one with curves when you want to go from a large size to a small. Browsers appear to typically use bi-linear (2×2 sampling) interpolation with the canvas element rather than bi-cubic (4×4 sampling) for (likely) performance reasons. If the step is … Read more
eval expects a string with expression representing valid Ruby code.