Mercurial > cortex

     1 #+title: Fun with Gabor Filters

     2 #+author: Robert McIntyre

     3 #+email: rlm@mit.edu

     4 #+description: gabor filters in clojure with opencv

     5 #+keywords: computer vision, jMonkeyEngine3, clojure, opencv

     6 #+SETUPFILE: ../../aurellem/org/setup.org

     7 #+INCLUDE: ../../aurellem/org/level-0.org

     8 #+babel: :mkdirp yes :noweb yes :exports both

     9 

    10 

    11 

    12 #+name: gabor

    13 #+begin_src clojure

    14 (ns cortex.gabor

    15   (:import org.opencv.core.CvType)

    16   (:import java.awt.image.BufferedImage)

    17   (:import ij.ImagePlus)

    18   (:import org.opencv.core.Mat)

    19   (:use cortex.sense)

    20   (:use cortex.util))

    21 

    22 (defn load-opencv

    23   "Load the opencv native library. Must be called before any OpenCV

    24   stuff is used."

    25   []

    26   (clojure.lang.RT/loadLibrary "opencv_java249"))

    27 

    28 (defn make-kernel []

    29   (let [r (org.opencv.core.Mat. 5 5 CvType/CV_32F)]

    30     (.put r 0 0 (float-array (map (fn [_] (rand)) (range 25))))

    31     (println (.dump r))

    32 

    33     r

    34 

    35 

    36     ))

    37 

    38 (defn gabor-kernel [sigma aspect-ratio theta wavelength phase-offset]

    39   

    40   ;; first, find the size of the kernel which is required

    41   (let [square #(expt % 2)

    42         rotated (fn [[x y]]

    43                   [(+ (* x (Math/cos theta)) (* y (Math/sin theta)))

    44                    (- (* y (Math/cos theta))  (* x (Math/sin theta)))])

    45                              

    46         gaussian (fn [[x y]]

    47                    (let [[x' y'] (rotated [x y])]

    48                      (Math/exp (- (/ (+ (square x')

    49                                         (square (* aspect-ratio y')))

    50                                    (* 2 (square sigma)))))))

    51         sinusoid (fn [[x y]]

    52                    (let [[x' y'] (rotated [x y])]

    53                      (Math/cos

    54                       (+ (* 2 Math/PI (/ x' wavelength))

    55                          phase-offset))))

    56 

    57         half-width

    58         (let [std-dev-capture 5]

    59           (max

    60            (int (* std-dev-capture (/ sigma aspect-ratio)))

    61            (int (* std-dev-capture sigma))

    62            (int (* std-dev-capture (/ aspect-ratio sigma)))))

    63 

    64         grid (let [axis (range (- half-width) (inc half-width))]

    65                (for [y (reverse axis) x axis] (vector x y)))

    66 

    67         scale (reduce + (map gaussian grid))

    68         

    69         gabor (fn [[x y :as coord]]

    70                 (* (sinusoid coord) (gaussian coord) (/ scale)))

    71 

    72         mat-width (+ 1 (* 2 half-width))

    73         mat (Mat. mat-width mat-width CvType/CV_32F)]

    74     

    75     (.put mat 0 0 (float-array (map gabor grid)))

    76     mat))

    77 

    78 

    79 (defn draw-kernel! [kernel img-path]

    80   (let [output img-path

    81         size (.size kernel)

    82         width (int (.width size))

    83         height (int (.height size))

    84         tmp-array (float-array (* width height))]

    85 

    86     ;; read values from matrix.

    87     (.get kernel 0 0 tmp-array)

    88 

    89     ;; find overall dynamic range of the filter

    90     (let [vals (vec tmp-array)

    91           low (apply min vals)

    92           high (apply max vals)

    93           scaled-vals (map #(* 255 (- % low) (/ (- high low))) vals)

    94           new-mat (Mat. height width CvType/CV_32F)]

    95       (.put new-mat 0 0 (float-array scaled-vals))

    96       (org.opencv.highgui.Highgui/imwrite output new-mat))))

    97 

    98 (defn show-kernel [kernel]

    99   (let [img-path "/home/r/proj/cortex/tmp/kernel.png"]

   100     (draw-kernel kernel img-path)

   101     (view (ImagePlus. output))))

   102 

   103 (defn print-kernel [kernel]

   104   (println (.dump kernel)))

   105                            

   106 

   107         

   108                       

   109          

   110         

   111   

   112 

   113 

   114 (defn convolve-practice []

   115   (let [input "/home/r/proj/cortex/images/dominos.jpg"

   116         

   117         

   118         output "/home/r/ppp.png"

   119 

   120         i (org.opencv.highgui.Highgui/imread input)

   121 

   122         kernel (gabor-kernel 10 1 (/ Math/PI 2) 10 0)

   123 

   124         new-mat (Mat.)

   125                 

   126         ]

   127 

   128     (org.opencv.imgproc.Imgproc/filter2D  i new-mat CvType/CV_32F kernel)

   129     

   130     (org.opencv.highgui.Highgui/imwrite "/home/r/ppp.png" new-mat)

   131     

   132     (view (ImagePlus. input))

   133     (view (ImagePlus. output))))

   134 

   135   

   136 

   137 

   138 

   139 

   140 

   141 (comment

   142   ;; these work

   143   (def i (org.opencv.highgui.Highgui/imread

   144           "/home/r/proj/cortex/images/dominos.jpg"))

   145   

   146   (org.opencv.highgui.Highgui/imwrite "/home/r/ppp.png" i)

   147 )

   148 #+end_src

   149 

   150 

   151 

   152 * COMMENT Generate Source

   153 #+begin_src clojure :tangle ../src/cortex/gabor.clj

   154 <<gabor>>

   155 #+end_src
author	Robert McIntyre <rlm@mit.edu>
date	Thu, 07 Mar 2013 03:27:42 +0000
parents	fc5bb270596a
children	4b229dc028b6