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

    29   

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

    31   (let [square #(expt % 2)

    32         rotated (fn [[x y]]

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

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

    35                              

    36         gaussian (fn [[x y]]

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

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

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

    40                                    (* 2 (square sigma)))))))

    41         sinusoid (fn [[x y]]

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

    43                      (Math/cos

    44                       (+ (* 2 Math/PI (/ x' wavelength))

    45                          phase-offset))))

    46 

    47         half-width

    48         (let [std-dev-capture 5]

    49           (max

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

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

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

    53 

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

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

    56 

    57         scale (reduce + (map gaussian grid))

    58         

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

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

    61 

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

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

    64     

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

    66     mat))

    67 

    68 

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

    70   (let [output img-path

    71         size (.size kernel)

    72         width (int (.width size))

    73         height (int (.height size))

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

    75 

    76     ;; read values from matrix.

    77     (.get kernel 0 0 tmp-array)

    78 

    79     ;; find overall dynamic range of the filter

    80     (let [vals (vec tmp-array)

    81           low (apply min vals)

    82           high (apply max vals)

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

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

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

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

    87 

    88 (defn show-kernel [kernel]

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

    90     (draw-kernel! kernel img-path)

    91     (view (ImagePlus. output))))

    92 

    93 (defn print-kernel [kernel]

    94   (println (.dump kernel)))

    95                            

    96 (defn convolve-practice []

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

    98         

    99         

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

   101 

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

   103 

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

   105 

   106         new-mat (Mat.)

   107                 

   108         ]

   109 

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

   111     

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

   113     

   114     (view (ImagePlus. input))

   115     (view (ImagePlus. output))))

   116 

   117 #+end_src

   118 

   119 

   120 

   121 * COMMENT Generate Source

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

   123 <<gabor>>

   124 #+end_src
author	Robert McIntyre <rlm@mit.edu>
date	Thu, 07 Mar 2013 03:28:26 +0000
parents	09461dce2e2f
children	9fa92af29c3a