Adding Euclid Eraser to mixer2

src/mixer2/CMakeLists.txt

@@ -19,6 +19,7 @@ add_subdirectory (darken)
 add_subdirectory (difference)
 add_subdirectory (divide)
 add_subdirectory (dodge)
+add_subdirectory (euclid_eraser)
 add_subdirectory (grain_extract)
 add_subdirectory (grain_merge)
 add_subdirectory (hardlight)

src/mixer2/euclid_eraser/CMakeLists.txt

@@ -0,0 +1,11 @@
+set (SOURCES euclid_eraser.cpp)
+set (TARGET euclid_eraser)
+
+if (MSVC)
+  set (SOURCES ${SOURCES} ${FREI0R_1_1_DEF})
+endif (MSVC)
+
+add_library (${TARGET}  MODULE ${SOURCES})
+set_target_properties (${TARGET} PROPERTIES PREFIX "")
+
+install (TARGETS ${TARGET} LIBRARY DESTINATION ${LIBDIR})

src/mixer2/euclid_eraser/euclid_eraser.cpp

@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// Copyright (C) 2024 Erik H. Beck, [email protected]
+// https://www.gnu.org/licenses/old-licenses/gpl-2.0-standalone.html
+
+/* This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA
+ *
+ * Also see:
+ *
+ * https://www.gnu.org/licenses/old-licenses/gpl-2.0-standalone.html
+ *
+ */
+
+/** This is the source file for the euclid eraser two-input mixer for
+    frei0r. It uses euclidean distance to remove a static background
+    from a video. See file ./euclid_eraser.md for more info
+*/
+
+#include <math.h>
+#include "frei0r.hpp"
+#include "frei0r/math.h"
+
+#define NBYTES 4 
+#define CHANNELS 3 // Actually 4; 0-3
+
+double euclidDistance(uint8_t x_r, uint8_t x_g, uint8_t x_b,
+		      uint8_t y_r, uint8_t y_g, uint8_t y_b)
+   {
+   //calculating color channel differences for next steps
+   double red_d = x_r - y_r;
+   double green_d = x_g - y_g;
+   double blue_d = x_b - y_b; 
+
+   double sq_sum, dist;
+
+   //calculating Euclidean distance
+   sq_sum = pow(red_d, 2) + pow(green_d, 2) + pow (blue_d, 2);
+   dist = sqrt(sq_sum);                  
+
+   return dist;
+   }
+
+
+class euclid_eraser : public frei0r::mixer2
+{
+
+public:
+  euclid_eraser(unsigned int width, unsigned int height)
+  {
+    threshold = 5.6;      // Default distance threshold value
+    register_param(threshold, "threshold", "Matching Threshold");
+  }
+
+  void update(double time,
+              uint32_t* out,
+              const uint32_t* in1,
+              const uint32_t* in2)
+  {
+
+    const uint8_t *src1 = reinterpret_cast<const uint8_t*>(in1); //frst track (0)
+    const uint8_t *src2 = reinterpret_cast<const uint8_t*>(in2); //second trk (1)
+    uint8_t *dst = reinterpret_cast<uint8_t*>(out);
+
+    double e_dist;
+
+    uint32_t sizeCounter = size;
+    uint32_t b;
+
+    while (sizeCounter--)
+      {
+
+	// Loop over rgb
+	// Copy pixels from src2 to destination
+
+	for (b=0; b<3; b++)
+	  {
+	    dst[b]=src2[b];
+	  }
+	e_dist=euclidDistance(src1[0],src1[1],src1[2],
+			      src2[0],src2[1],src2[2]);
+
+	if (e_dist <=  euclid_eraser::threshold) {
+	    // Make alpha channel for pixel fully transparent
+	    dst[3]=0;
+	  }
+	else {
+	  // Make alpha channel for the pixel fully opaque
+	  dst[3]=255;
+	}
+
+	src1 += NBYTES;
+	src2 += NBYTES;
+	dst  += NBYTES;
+      }
+
+  }
+private:
+  double threshold;
+
+};
+
+frei0r::construct<euclid_eraser> plugin("euclid_eraser",
+	"Erasing backgrounds with euclidian distance",
+        "Erik H. Beck",
+        0,1,
+        F0R_COLOR_MODEL_RGBA8888);
+

src/mixer2/euclid_eraser/euclid_eraser.md

@@ -0,0 +1,88 @@
+# Euclid Eraser Notes #
+
+## Overview ##
+This is about the Euclid Eraser mixer.
+
+
+## Description ##
+
+This class is intended to operate as a mixer, taking two inputs and
+yielding one output.
+
+The first input is a reference input, such as a single image or a
+stretched video of a single image.
+
+The second input is the video stream to operate on.
+
+The output is a clone of the RGB data of the second input, but with
+the alpha channel modified.
+
+This mixer takes the (first) reference input, such as a static
+background, and removes it from every frame in the video stream of the
+second input.
+
+The alpha channel on the output is based on the euclidian distance of
+the two input coordinates in 3-d RGB space. If the calculated distance
+betwen the two inputs for a given pixel is less than a provided
+(variable) threshold amount, that indicates the pixel in the
+background (reference) image is the same or similar enough to the
+operational (second) input that is part of the background to be
+removed, and the transparency is set to fully transparent via the
+alpha channel (set to 0).
+
+If the calcuated distance exceeds the threshold, then that pixel is
+part of the foreground image to be retained, and the transparency
+of it is set to be fully opaque (alpha channel for that pixel set
+to 255).
+
+## Basic Algorithm ##
+The basic comparison algorithm is:
+
+
+x is reference image
+y is comparison image to remove reference image from
+
+
+```
+float euclidDistance (int x_r, int x_g, int x_b, int y_r, int y_g, int y_b) 
+{
+   //calculating color channel differences for next steps
+   float red_d = x_r - y_r;
+   float green_d = x_g - y_g;
+   float blue_d = x_b - y_b; 
+  
+   float sq_sum, dist;
+
+   //calculating Euclidean distance
+   sq_sum = pow(red_d, 2) + pow(green_d, 2) + pow (blue_d)
+   dist = sqrt(sq_sum);    
+   
+   return dist;
+}
+```
+
+## Note ##
+
+Here's a handy reminder on how the bits map up.
+
+```
+      red_src1    = src1[0];
+      green_src1  = src1[1];
+      blue_src1   = src1[2];
+      alpha_src1  = src1[3]
+      
+      red_src2    = src2[0];
+      green_src2  = src2[1];
+      blue_src2   = src2[2];
+      alpha_src2  = src2[3]
+```
+## Further Work ##
+
+Some potential improvements are:
+
+- Faster performance (math calculations, others)
+- Options beyond binary for alpha
+
+
+
+