Gaussian.cc
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```00001 #include "Gaussian.h"
00002 #include <iostream>
00003
00004 namespace AprilTags {
00005
00006 bool Gaussian::warned = false;
00007
00008 std::vector<float> Gaussian::makeGaussianFilter(float sigma, int n) {
00009   std::vector<float> f(n,0.0f);
00010
00011   if (sigma == 0) {
00012     for (int i = 0; i < n; i++)
00013       f[i] = 0;
00014     f[n/2] = 1;
00015     return f;
00016   }
00017
00018   double const inv_variance = 1./(2*sigma*sigma);
00019   float sum = 0;
00020   for (int i = 0; i < n; i++) {
00021     int j = i - n/2;
00022     f[i] = (float)std::exp(-j*j * inv_variance);
00023     sum += f[i];
00024   }
00025
00026   // normalize the gaussian
00027   for (int i = 0; i < n; i++)
00028     f[i] /= sum;
00029
00030   return f;
00031 }
00032
00033 void Gaussian::convolveSymmetricCentered(const std::vector<float>& a, unsigned int aoff, unsigned int alen,
00034                                         const std::vector<float>& f, std::vector<float>& r, unsigned int roff) {
00035   if ((f.size()&1)== 0 && !warned) {
00036     std::cout<<"convolveSymmetricCentered Warning: filter is not odd length\n";
00037     warned = true;
00038   }
00039
00040   for (size_t i = f.size()/2; i < f.size(); i++) {
00041     double acc = 0;
00042     for (size_t j = 0; j < f.size(); j++) {
00043       if ((aoff + i) < j || (aoff + i) >= (alen + j))
00044         acc += a[aoff] * f[j];
00045       else
00046         acc += a[aoff + i - j] * f[j];
00047     }
00048     r[roff + i - f.size()/2] = (float)acc;
00049   }
00050
00051   for (size_t i = f.size(); i < alen; i++) {
00052     double acc = 0;
00053     for (unsigned int j = 0; j < f.size(); j++) {
00054       acc += a[aoff + i - j] * f[j];
00055     }
00056     r[roff + i - f.size()/2] = (float)acc;
00057   }
00058
00059   for (size_t i = alen; i < alen + f.size()/2; i++) {
00060     double acc = 0;
00061     for (size_t j = 0; j < f.size(); j++) {
00062       if ((aoff + i) >= (alen + j) || (aoff + i) < j)
00063         acc += a[aoff + alen - 1] * f[j];
00064       else
00065         acc += a[aoff + i - j] * f[j];
00066     }
00067     r[roff + i - f.size()/2] = (float)acc;
00068   }
00069 }
00070
00071 } // namespace
```

apriltags
Author(s): Michael Kaess, Hordur Johannson
autogenerated on Thu Jun 6 2019 20:53:23