added threshold and adpative threshold

scikits/image/opencv/opencv_backend.c

@@ -1,4 +1,4 @@
-/* Generated by Cython 0.11.3 on Sat Oct 24 16:06:03 2009 */
+/* Generated by Cython 0.11.3 on Sat Oct 24 17:38:28 2009 */
 
 #define PY_SSIZE_T_CLEAN
 #include "Python.h"

scikits/image/opencv/opencv_constants.py

@@ -3,7 +3,6 @@
 # Image Processing Constants
 ############################################
 
-
 CV_BLUR_NO_SCALE = 0
 CV_BLUR = 1
 CV_GAUSSIAN = 2
@@ -27,6 +26,16 @@ CV_SHAPE_CROSS = 1
 CV_SHAPE_ELLIPSE = 2
 CV_SHAPE_CUSTOM = 100
 
+CV_THRESH_BINARY = 0
+CV_THRESH_BINARY_INV = 1
+CV_THRESH_TRUNC = 2
+CV_THRESH_TOZERO = 3
+CV_THRESH_TOZERO_INV = 4
+CV_THRESH_MASK = 7
+CV_THRESH_OTSU = 8 # this must be combined with other flags
+CV_ADAPTIVE_THRESH_MEAN_C = 0
+CV_ADAPTIVE_THRESH_GAUSSIAN_C = 1
+
 CV_MOP_OPEN = 2
 CV_MOP_CLOSE = 3
 CV_MOP_GRADIENT = 4

scikits/image/opencv/opencv_cv.pyx

@@ -233,6 +233,18 @@ ctypedef void (*cvCvtColorPtr)(IplImage*, IplImage*, int)
 cdef cvCvtColorPtr c_cvCvtColor
 c_cvCvtColor = (<cvCvtColorPtr*><size_t>ctypes.addressof(cv.cvCvtColor))[0]
 
+# cvThreshold
+ctypedef double (*cvThresholdPtr)(IplImage*, IplImage*, double, double, int)
+cdef cvThresholdPtr c_cvThreshold
+c_cvThreshold = (<cvThresholdPtr*><size_t>ctypes.addressof(cv.cvThreshold))[0]
+
+# cvAdaptiveThreshold
+ctypedef void (*cvAdaptiveThresholdPtr)(IplImage*, IplImage*, double, int, int,
+                                        int, double)
+cdef cvAdaptiveThresholdPtr c_cvAdaptiveThreshold
+c_cvAdaptiveThreshold = (<cvAdaptiveThresholdPtr*><size_t>
+                         ctypes.addressof(cv.cvAdaptiveThreshold))[0]
+
 # cvCalibrateCamera2
 ctypedef void (*cvCalibrateCamera2Ptr)(CvMat*, CvMat*, CvMat*,
        CvSize, CvMat*, CvMat*, CvMat*, CvMat*, int)
@@ -1163,6 +1175,64 @@ def cvCvtColor(np.ndarray src, int code):
 
     return out
 
+def cvThreshold(np.ndarray src, double threshold, double max_value=255,
+                int threshold_type=CV_THRESH_BINARY):
+
+    validate_array(src)
+    assert_nchannels(src, [1])
+    assert_dtype(src, [UINT8, FLOAT32])
+
+    use_otsu = (threshold_type & CV_THRESH_OTSU) != 0
+    if use_otsu:
+        assert_dtype(src, [UINT8])
+
+    cdef np.ndarray out = new_array_like(src)
+
+    cdef IplImage srcimg
+    cdef IplImage outimg
+    populate_iplimage(src, &srcimg)
+    populate_iplimage(out, &outimg)
+
+    threshold = c_cvThreshold(&srcimg, &outimg, threshold, max_value,
+                              threshold_type)
+
+    if use_otsu:
+        return (out, threshold)
+    else:
+        return out
+
+def cvAdaptiveThreshold(np.ndarray src, double max_value,
+                        int adaptive_method=CV_ADAPTIVE_THRESH_MEAN_C,
+                        int threshold_type=CV_THRESH_BINARY,
+                        int block_size=3, double param1=5):
+
+    validate_array(src)
+    assert_nchannels(src, [1])
+    assert_dtype(src, [UINT8])
+
+    if (adaptive_method!=CV_ADAPTIVE_THRESH_MEAN_C and
+        adaptive_method!=CV_ADAPTIVE_THRESH_GAUSSIAN_C):
+        raise ValueError('Invalid adaptive method')
+
+    if (threshold_type!=CV_THRESH_BINARY and
+        threshold_type!=CV_THRESH_BINARY_INV):
+        raise ValueError('Invalid threshold type')
+
+    if (block_size % 2 != 1 or block_size <= 1):
+        raise ValueError('block size must be and odd number and greater than 1')
+
+    cdef np.ndarray out = new_array_like(src)
+
+    cdef IplImage srcimg
+    cdef IplImage outimg
+    populate_iplimage(src, &srcimg)
+    populate_iplimage(out, &outimg)
+
+    c_cvAdaptiveThreshold(&srcimg, &outimg, max_value, adaptive_method,
+                          threshold_type, block_size, param1)
+
+    return out
+
 def cvCalibrateCamera2(np.ndarray object_points, np.ndarray image_points,
            np.ndarray point_counts, image_size):
 

scikits/image/opencv/tests/test_opencv_cv.py

@@ -200,6 +200,23 @@ class TestCvtColor(OpenCVTest):
         cvCvtColor(self.lena_GRAY_U8, CV_GRAY2BGR555)
 
 
+class TestThreshold(OpenCVTest):
+    @opencv_skip
+    def test_cvThreshold(self):
+        cvThreshold(self.lena_GRAY_U8, 100, 255, CV_THRESH_BINARY)
+        cvThreshold(self.lena_GRAY_U8, 100, 255, CV_THRESH_BINARY_INV)
+        cvThreshold(self.lena_GRAY_U8, 100, threshold_type=CV_THRESH_TRUNC)
+        cvThreshold(self.lena_GRAY_U8, 100, threshold_type=CV_THRESH_TOZERO)
+        cvThreshold(self.lena_GRAY_U8, 100, threshold_type=CV_THRESH_TOZERO_INV)
+        cvThreshold(self.lena_GRAY_U8, 100, 1, CV_THRESH_BINARY+CV_THRESH_OTSU)
+
+
+class TestAdaptiveThreshold(OpenCVTest):
+    @opencv_skip
+    def test_cvAdaptiveThreshold(self):
+        cvAdaptiveThreshold(self.lena_GRAY_U8, 100)
+
+
 class TestFindChessboardCorners(object):
     @opencv_skip
     def test_cvFindChessboardCorners(self):