summaryrefslogtreecommitdiff
path: root/silx/math/medianfilter/include/median_filter.hpp
diff options
context:
space:
mode:
Diffstat (limited to 'silx/math/medianfilter/include/median_filter.hpp')
-rw-r--r--silx/math/medianfilter/include/median_filter.hpp229
1 files changed, 229 insertions, 0 deletions
diff --git a/silx/math/medianfilter/include/median_filter.hpp b/silx/math/medianfilter/include/median_filter.hpp
new file mode 100644
index 0000000..78d6c5a
--- /dev/null
+++ b/silx/math/medianfilter/include/median_filter.hpp
@@ -0,0 +1,229 @@
+/*##########################################################################
+#
+# Copyright (c) 2017 European Synchrotron Radiation Facility
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
+#
+# ###########################################################################*/
+// __authors__ = ["H. Payno"]
+// __license__ = "MIT"
+// __date__ = "10/02/2017"
+
+#ifndef MEDIAN_FILTER
+#define MEDIAN_FILTER
+
+#include <vector>
+#include <assert.h>
+#include <algorithm>
+#include <signal.h>
+#include <iostream>
+
+// Modes for the median filter
+enum MODE{
+ NEAREST=0,
+ REFLECT=1,
+ MIRROR=2,
+ SHRINK=3
+};
+
+// Simple function browsing a deque and registring the min and max values
+// and if those values are unique or not
+template<typename T>
+void getMinMax(std::vector<const T*>& v, T& min, T&max,
+ typename std::vector<const T*>::const_iterator end){
+ // init min and max values
+ typename std::vector<const T*>::const_iterator it = v.begin();
+ if (v.size() == 0){
+ raise(SIGINT);
+ }else{
+ min = max = *(*it);
+ }
+ it++;
+
+ // Browse all the deque
+ while(it!=end){
+ // check if repeated (should always be before min/max setting)
+ if(*(*it) > max) max = *(*it);
+ if(*(*it) < min) min = *(*it);
+
+ it++;
+ }
+}
+
+template<typename T>
+bool cmp(const T* a, const T* b){
+ return *a < *b;
+}
+
+// apply the median filter only on limited part of the vector
+template<typename T>
+const T* median(std::vector<const T*>& v, int window_size) {
+ std::nth_element(v.begin(), v.begin() + window_size/2, v.begin()+window_size, cmp<T>);
+ return v[window_size/2];
+}
+
+template<typename T>
+void print_window(std::vector<const T*>& v,
+ typename std::vector<const T*>::const_iterator end){
+ typename std::vector<const T*>::const_iterator it;
+ for(it = v.begin(); it != end; ++it){
+ std::cout << *(*it) << " ";
+ }
+ std::cout << std::endl;
+}
+
+// return the index into 0, (length_max - 1) in reflect mode
+int reflect(int index, int length_max){
+ int res = index;
+ // if the index is negative get the positive symetrical value
+ if(res < 0){
+ res += 1;
+ res = -res;
+ }
+ // then apply the reflect algorithm. Frequence is 2 max length
+ res = res % (2*length_max);
+ if(res >= length_max){
+ res = 2*length_max - res -1;
+ res = res % length_max;
+ }
+ return res;
+}
+
+// return the index into 0, (length_max - 1) in mirror mode
+int mirror(int index, int length_max){
+ int res = index;
+ // if the index is negative get the positive symetrical value
+ if(res < 0){
+ res = -res;
+ }
+
+ int rightLimit = length_max -1;
+ // apply the redundancy each two right limit
+ res = res % (2*rightLimit);
+ if(res >= length_max){
+ int distToRedundancy = (2*rightLimit) - res;
+ res = distToRedundancy;
+ }
+ return res;
+}
+
+// Browse the column of pixel_x
+template<typename T>
+void median_filter(
+ const T* input,
+ T* output,
+ int* kernel_dim, // two values : 0:width, 1:height
+ int* image_dim, // two values : 0:width, 1:height
+ int y_pixel, // the x pixel to process
+ int x_pixel_range_min,
+ int x_pixel_range_max,
+ bool conditional,
+ int pMode){
+
+ assert(kernel_dim[0] > 0);
+ assert(kernel_dim[1] > 0);
+ assert(y_pixel >= 0);
+ assert(image_dim[0] > 0);
+ assert(image_dim[1] > 0);
+ assert(y_pixel >= 0);
+ assert(y_pixel < image_dim[0]);
+ assert(x_pixel_range_max < image_dim[1]);
+ assert(x_pixel_range_min <= x_pixel_range_max);
+ // kernel odd assertion
+ assert((kernel_dim[0] - 1)%2 == 0);
+ assert((kernel_dim[1] - 1)%2 == 0);
+
+ // # this should be move up to avoid calculation each time
+ int halfKernel_x = (kernel_dim[1] - 1) / 2;
+ int halfKernel_y = (kernel_dim[0] - 1) / 2;
+
+ MODE mode = static_cast<MODE>(pMode);
+
+ // init buffer
+ std::vector<const T*> window_values(kernel_dim[0]*kernel_dim[1]);
+
+ for(int x_pixel=x_pixel_range_min; x_pixel <= x_pixel_range_max; x_pixel ++ ){
+ typename std::vector<const T*>::iterator it = window_values.begin();
+ // fill the vector
+ for(int win_y=y_pixel-halfKernel_y; win_y<= y_pixel+halfKernel_y; win_y++)
+ {
+ for(int win_x = x_pixel-halfKernel_x; win_x <= x_pixel+halfKernel_x; win_x++)
+ {
+ int index_x = win_x;
+ int index_y = win_y;
+ switch(mode){
+ case NEAREST:
+ index_x = std::min(std::max(win_x, 0), image_dim[1] - 1);
+ index_y = std::min(std::max(win_y, 0), image_dim[0] - 1);
+ break;
+
+ case REFLECT:
+ index_x = reflect(win_x, image_dim[1]);
+ index_y = reflect(win_y, image_dim[0]);
+ break;
+
+ case MIRROR:
+ index_x = mirror(win_x, image_dim[1]);
+ index_y = mirror(win_y, image_dim[0]);
+ break;
+ case SHRINK:
+ if((index_x < 0) || (index_x > image_dim[1] -1)){
+ continue;
+ }
+ if((index_y < 0) || (index_y > image_dim[0] -1)){
+ continue;
+ }
+ break;
+ }
+ *it = (&input[index_y*image_dim[1] + index_x]);
+ ++it;
+ }
+ }
+
+ // get end of the windows. This is needed since in shrink mode we are
+ // not sure to fill the entire window.
+ typename std::vector<const T*>::iterator window_end;
+ int window_size = kernel_dim[0]*kernel_dim[1];
+ if(mode == SHRINK){
+ int x_shrink_ker_dim = std::min(x_pixel+halfKernel_x, image_dim[1]-1) - std::max(0, x_pixel-halfKernel_x)+1;
+ int y_shrink_ker_dim = std::min(y_pixel+halfKernel_y, image_dim[0]-1) - std::max(0, y_pixel-halfKernel_y)+1;
+ window_size = x_shrink_ker_dim*y_shrink_ker_dim;
+ window_end = window_values.begin() + window_size;
+ }else{
+ window_end = window_values.end();
+ }
+
+ // apply the median value if needed for this pixel
+ const T* currentPixelValue = &input[image_dim[1]*y_pixel + x_pixel];
+ if (conditional == true){
+ T min = 0;
+ T max = 0;
+ getMinMax(window_values, min, max, window_end);
+ if ((*currentPixelValue == max) || (*currentPixelValue == min)){
+ output[image_dim[1]*y_pixel + x_pixel] = *(median<T>(window_values, window_size));
+ }else{
+ output[image_dim[1]*y_pixel + x_pixel] = *currentPixelValue;
+ }
+ }else{
+ output[image_dim[1]*y_pixel + x_pixel] = *(median<T>(window_values, window_size));
+ }
+ }
+}
+
+#endif // MEDIAN_FILTER