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1 #+title: Fun with Gabor Filters
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2 #+author: Robert McIntyre
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3 #+email: rlm@mit.edu
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4 #+description: gabor filters in clojure with opencv
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5 #+keywords: computer vision, jMonkeyEngine3, clojure, opencv
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6 #+SETUPFILE: ../../aurellem/org/setup.org
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7 #+INCLUDE: ../../aurellem/org/level-0.org
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8 #+babel: :mkdirp yes :noweb yes :exports both
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9
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10
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11
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12 #+name: gabor
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13 #+begin_src clojure
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14 (ns cortex.gabor
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15 (:import org.opencv.core.CvType)
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16 (:import java.awt.image.BufferedImage)
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17 (:import ij.ImagePlus)
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18 (:import org.opencv.core.Mat)
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19 (:use cortex.sense)
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20 (:use cortex.util))
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21
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22 (defn load-opencv
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23 "Load the opencv native library. Must be called before any OpenCV
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24 stuff is used."
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25 []
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26 (clojure.lang.RT/loadLibrary "opencv_java249"))
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27
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28 (defn make-kernel []
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29 (let [r (org.opencv.core.Mat. 5 5 CvType/CV_32F)]
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30 (.put r 0 0 (float-array (map (fn [_] (rand)) (range 25))))
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31 (println (.dump r))
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32
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33 r
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34
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35
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36 ))
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37
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38 (defn gabor-kernel [sigma aspect-ratio theta wavelength phase-offset]
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39
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40 ;; first, find the size of the kernel which is required
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41 (let [square #(expt % 2)
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42 rotated (fn [[x y]]
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43 [(+ (* x (Math/cos theta)) (* y (Math/sin theta)))
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44 (- (* y (Math/cos theta)) (* x (Math/sin theta)))])
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45
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46 gaussian (fn [[x y]]
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47 (let [[x' y'] (rotated [x y])]
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48 (Math/exp (- (/ (+ (square x')
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49 (square (* aspect-ratio y')))
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50 (* 2 (square sigma)))))))
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51 sinusoid (fn [[x y]]
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52 (let [[x' y'] (rotated [x y])]
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53 (Math/cos
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54 (+ (* 2 Math/PI (/ x' wavelength))
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55 phase-offset))))
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56
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57 half-width
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58 (let [std-dev-capture 5]
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59 (max
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60 (int (* std-dev-capture (/ sigma aspect-ratio)))
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61 (int (* std-dev-capture sigma))
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62 (int (* std-dev-capture (/ aspect-ratio sigma)))))
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63
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64 grid (let [axis (range (- half-width) (inc half-width))]
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65 (for [y (reverse axis) x axis] (vector x y)))
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66
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67 scale (reduce + (map gaussian grid))
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68
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69 gabor (fn [[x y :as coord]]
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70 (* (sinusoid coord) (gaussian coord) (/ scale)))
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71
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72 mat-width (+ 1 (* 2 half-width))
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73 mat (Mat. mat-width mat-width CvType/CV_32F)]
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74
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75 (.put mat 0 0 (float-array (map gabor grid)))
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76 mat))
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77
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78
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79 (defn draw-kernel! [kernel img-path]
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80 (let [output img-path
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81 size (.size kernel)
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82 width (int (.width size))
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83 height (int (.height size))
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84 tmp-array (float-array (* width height))]
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85
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86 ;; read values from matrix.
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87 (.get kernel 0 0 tmp-array)
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88
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89 ;; find overall dynamic range of the filter
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90 (let [vals (vec tmp-array)
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91 low (apply min vals)
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92 high (apply max vals)
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93 scaled-vals (map #(* 255 (- % low) (/ (- high low))) vals)
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94 new-mat (Mat. height width CvType/CV_32F)]
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95 (.put new-mat 0 0 (float-array scaled-vals))
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96 (org.opencv.highgui.Highgui/imwrite output new-mat))))
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97
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98 (defn show-kernel [kernel]
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99 (let [img-path "/home/r/proj/cortex/tmp/kernel.png"]
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100 (draw-kernel kernel img-path)
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101 (view (ImagePlus. output))))
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102
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103 (defn print-kernel [kernel]
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104 (println (.dump kernel)))
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105
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106
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107
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108
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109
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110
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111
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112
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113
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114 (defn convolve-practice []
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115 (let [input "/home/r/proj/cortex/images/dominos.jpg"
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116
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117
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118 output "/home/r/ppp.png"
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119
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120 i (org.opencv.highgui.Highgui/imread input)
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121
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122 kernel (gabor-kernel 10 1 (/ Math/PI 2) 10 0)
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123
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124 new-mat (Mat.)
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125
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126 ]
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127
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128 (org.opencv.imgproc.Imgproc/filter2D i new-mat CvType/CV_32F kernel)
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129
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130 (org.opencv.highgui.Highgui/imwrite "/home/r/ppp.png" new-mat)
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131
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132 (view (ImagePlus. input))
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133 (view (ImagePlus. output))))
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134
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135
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136
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137
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138
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139
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140
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141 (comment
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142 ;; these work
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143 (def i (org.opencv.highgui.Highgui/imread
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144 "/home/r/proj/cortex/images/dominos.jpg"))
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145
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146 (org.opencv.highgui.Highgui/imwrite "/home/r/ppp.png" i)
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147 )
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148 #+end_src
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149
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150
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151
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152 * COMMENT Generate Source
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153 #+begin_src clojure :tangle ../src/cortex/gabor.clj
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154 <<gabor>>
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155 #+end_src
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