Omzetting van karakters naar zwart wit

src/CharacterImageNormalizer.py

+from copy import deepcopy
+from GrayscaleImage import GrayscaleImage
+from LetterCropper import LetterCropper
+from GaussianFilter import GaussianFilter
+from numpy import resize, array, append, vstack, hstack, zeros
+
+class CharacterImageNormalizer:
+
+    def __init__(self, size=(60, 40), blur=1.1, crop_threshold=126):
+        self.size = size
+        self.gausse_filter = GaussianFilter(blur)
+        self.cropper = LetterCropper(crop_threshold)
+        
+    def normalize(self, image):
+        self.gausse_filter.filter(image)
+        GrayscaleImage.resize(image, (60,  60 / image.height * image.width))
+        self.increase_contrast(image)
+        self.to_black_white(image, 30)
+        self.cropper.crop_to_letter(image)
+        self.add_padding(image)
+
+    def add_padding(self, image):
+        data = array(image.data)
+         
+        top_bottom_padding = zeros((3, data.shape[1])) 
+        data = vstack((top_bottom_padding, data))
+        data = vstack((data, top_bottom_padding))
+        
+        left_right_padding = zeros((data.shape[0], 3))
+        data = hstack((left_right_padding, data))
+        data = hstack((data, left_right_padding))
+
+        extra_left_padding = zeros((data.shape[0], data.shape[0] - data.shape[1]))
+        data = hstack((extra_left_padding, data))
+          
+        image.data = data
+
+    def increase_contrast(self, image):
+        image.data -= image.data.min()
+        image.data /= image.data.max() / 255.0
+
+    def to_black_white(self, image, bla):
+        for y, x, value in image:
+            image.data[y, x] = 255 if value < bla else 0
\ No newline at end of file

src/LetterCropper.py

 from Rectangle import Rectangle
+import sys
 
 class LetterCropper:
 
-    def __init__(self, threshold = 0.9):
+    def __init__(self, threshold = 0.5):
         self.threshold = threshold
 
     def crop_to_letter(self, image):
@@ -17,7 +18,7 @@ class LetterCropper:
         max_y = 0
 
         for y, x, value in self.image:
-            if value < self.threshold:
+            if value > self.threshold:
                 if x < min_x: min_x = x
                 if y < min_y: min_y = y
                 if x > max_x: max_x = x
@@ -26,6 +27,6 @@ class LetterCropper:
         self.letter_bounds = Rectangle(
             min_x,
             min_y,
-            max_x - min_x ,
-            max_y - min_y
+            max_x - min_x + 1,
+            max_y - min_y + 1
         )

src/LicensePlate.py

@@ -3,11 +3,12 @@ from xml.dom.minidom import parse
 from Point import Point
 from Character import Character
 from GrayscaleImage import GrayscaleImage
-from NormalizedCharacterImage import NormalizedCharacterImage
+from CharacterImageNormalizer import CharacterImageNormalizer
 
 class LicensePlate:
 
     def __init__(self, folder_nr, file_nr):
+        self.character_normalizer = CharacterImageNormalizer(size=(60, 40), blur=1.1, crop_threshold=125)
         filename = '%04d/00991_%04d%02d' % (folder_nr, folder_nr, file_nr)
 
         self.dom = parse('../images/Infos/%s.info' % filename)
@@ -89,6 +90,17 @@ class LicensePlate:
         x2, y2 = corners[2].to_tuple()
         x3, y3 = corners[3].to_tuple()
         
+        extra_space = 3
+        
+        x0 -= extra_space
+        y0 -= extra_space
+        x1 += extra_space
+        y1 -= extra_space
+        x2 += extra_space
+        y2 += extra_space
+        x3 -= extra_space
+        y3 += extra_space
+
         M = max(x0, x1, x2, x3) - min(x0, x1, x2, x3)
         N = max(y0, y1, y2, y3) - min(y0, y1, y2, y3)
 
@@ -193,7 +205,9 @@ class LicensePlate:
                     value   = self.get_node("char", character).firstChild.data
                     corners = self.get_corners(character)
                     data    = self.retrieve_data(corners)
-                    image   = NormalizedCharacterImage(data=data)
+                    
+                    image   = GrayscaleImage(data=data)
+                    self.character_normalizer.normalize(image)
 
                     self.characters.append(Character(value, corners, image))
             else:

src/NormalizedCharacterImage.py

-from copy import deepcopy
-from GrayscaleImage import GrayscaleImage
-from LetterCropper import LetterCropper
-from GaussianFilter import GaussianFilter
-
-class NormalizedCharacterImage(GrayscaleImage):
-
-    def __init__(self, image=None, data=None, size=(60, 40), blur=1.1, crop_threshold=0.9):
-        if image != None:
-            GrayscaleImage.__init__(self, data=deepcopy(image.data))
-        elif data != None:
-            GrayscaleImage.__init__(self, data=deepcopy(data))
-        self.blur = blur
-        self.crop_threshold = crop_threshold
-        self.size = size
-        self.gausse_filter()
-        self.increase_contrast()
-        self.crop_to_letter()
-        self.resize()
-
-    def increase_contrast(self):
-        self.data -= self.data.min()
-        self.data /= self.data.max()
-
-    def gausse_filter(self):
-        filter = GaussianFilter(1.1)
-        filter.filter(self)
-
-    def crop_to_letter(self):
-        cropper = LetterCropper(0.9)
-        cropper.crop_to_letter(self)
-
-    def resize(self):
-        GrayscaleImage.resize(self, self.size)