Merge pull request #41 from drhoffma/master

Added feature matcher factory. Added Dense, GFTT, Harris, and RootSIF…

imutils/__init__.py

@@ -2,7 +2,7 @@
 # website:	http://www.pyimagesearch.com
 
 # set the version number
-__version__ = "0.4.3"
+__version__ = "0.4.4"
 
 # import the necessary packages
 from .convenience import translate

imutils/feature/__init__.py

@@ -1,4 +1,8 @@
 from .helpers import corners_to_keypoints
 from .factories import FeatureDetector_create
 from .factories import DescriptorExtractor_create
-from .gftt import GFTT
+from .factories import DescriptorMatcher_create
+from .dense import DENSE
+from .gftt import GFTT
+from .harris import HARRIS
+from .rootsift import RootSIFT

imutils/feature/dense.py

@@ -0,0 +1,24 @@
+import cv2
+
+class DENSE:
+    def __init__(self, step=6, radius=.5):
+        self.step = step
+        self.radius = radius
+
+    def detect(self, img):
+        # initialize our list of keypoints
+        kps = []
+
+        # loop over the height and with of the image, taking a `step`
+        # in each direction
+        for x in range(0, img.shape[1], self.step):
+            for y in range(0, img.shape[0], self.step):
+                # create a keypoint and add it to the keypoints list
+                kps.append(cv2.KeyPoint(x, y, self.radius))
+
+        # return the dense keypoints
+        return kps
+
+    def setInt(self, var, val):
+        if var == "initXyStep":
+            self.step = val

imutils/feature/factories.py

@@ -1,29 +1,46 @@
 #from .descriptors.rootsift import RootSIFT
 from ..convenience import is_cv2
 import cv2
+from .dense import DENSE
+from .gftt import GFTT
+from .harris import HARRIS
+from .rootsift import RootSIFT
 
 if is_cv2():
     FeatureDetector_create = cv2.FeatureDetector_create
     DescriptorExtractor_create = cv2.DescriptorExtractor_create
+    DescriptorMatcher_create = cv2.DescriptorMatcher_create
+
 else:
     try:
-        _DETECTOR_FACTORY = {"SIFT": cv2.xfeatures2d.SIFT_create,
-                             "SURF": cv2.xfeatures2d.SURF_create,
-                             "STAR": cv2.xfeatures2d.StarDetector_create,
-                             "MSER": cv2.MSER_create,
+        _DETECTOR_FACTORY = {"BRISK": cv2.BRISK_create,
+                             "DENSE": DENSE,
                              "FAST": cv2.FastFeatureDetector_create,
-                             "BRISK": cv2.BRISK_create,
-                             "ORB": cv2.ORB_create
+                             "GFTT": GFTT,
+                             "HARRIS": HARRIS,
+                             "MSER": cv2.MSER_create,
+                             "ORB": cv2.ORB_create,
+                             "SIFT": cv2.xfeatures2d.SIFT_create,
+                             "SURF": cv2.xfeatures2d.SURF_create,
+                             "STAR": cv2.xfeatures2d.StarDetector_create
                              }
 
         _EXTRACTOR_FACTORY = {"SIFT": cv2.xfeatures2d.SIFT_create,
-                              #"ROOTSIFT": RootSIFT,
+                              "ROOTSIFT": RootSIFT,
                               "SURF": cv2.xfeatures2d.SURF_create,
                               "BRIEF": cv2.xfeatures2d.BriefDescriptorExtractor_create,
                               "ORB": cv2.ORB_create,
                               "BRISK": cv2.BRISK_create,
                               "FREAK": cv2.xfeatures2d.FREAK_create
                               }
+
+        _MATCHER_FACTORY = {"BruteForce": cv2.DESCRIPTOR_MATCHER_BRUTEFORCE,
+                           "BruteForce-SL2": cv2.DESCRIPTOR_MATCHER_BRUTEFORCE_SL2,
+                           "BruteForce-L1": cv2.DESCRIPTOR_MATCHER_BRUTEFORCE_L1,
+                           "BruteForce-Hamming": cv2.DESCRIPTOR_MATCHER_BRUTEFORCE_HAMMING,
+                           "FlannBased": cv2.DESCRIPTOR_MATCHER_FLANNBASED
+                           }
+
     except AttributeError:
         _DETECTOR_FACTORY = {"MSER": cv2.MSER_create,
                              "FAST": cv2.FastFeatureDetector_create,
@@ -74,3 +91,16 @@ def DescriptorExtractor_create(extractor, *args, **kw_args):
             raise AttributeError("{} not a supported extractor".format(extractor))
 
         return extr(*args, **kw_args)
+
+    def DescriptorMatcher_create(matcher):
+        """
+
+        :param matcher: string of the type of descriptor matcher to return
+        :return: the matcher int
+        """
+        try:
+            extr = _MATCHER_FACTORY[matcher]
+        except KeyError:
+            raise AttributeError("{} not a supported matcher".format(matcher))
+
+        return cv2.DescriptorMatcher_create(extr)

imutils/feature/harris.py

@@ -0,0 +1,26 @@
+import cv2
+import numpy as np
+from .helpers import corners_to_keypoints
+
+
+class HARRIS:
+    def __init__(self, blockSize=2, apertureSize=3, k=0.1, T=0.02):
+        self.blockSize = blockSize
+        self.apertureSize = apertureSize
+        self.k = k
+        self.T = T
+
+    def detect(self, img):
+        # convert our input image to a floating point data type and then
+        # compute the Harris corner matrix
+        gray = np.float32(img)
+        H = cv2.cornerHarris(gray, self.blockSize, self.apertureSize, self.k)
+
+        # for every (x, y)-coordinate where the Harris value is above the
+        # threshold, create a keypoint (the Harris detector returns
+        # keypoint size a 3-pixel radius)
+        kps = np.argwhere(H > self.T * H.max())
+        kps = [cv2.KeyPoint(pt[1], pt[0], 3) for pt in kps]
+
+        # return the Harris keypoints
+        return kps

imutils/feature/rootsift.py

@@ -0,0 +1,31 @@
+# import the necessary packages
+import numpy as np
+import cv2
+from ..convenience import is_cv2
+from . import factories
+
+class RootSIFT:
+	def __init__(self):
+		# initialize the SIFT feature extractor
+		self.extractor = factories.DescriptorExtractor_create("SIFT")
+
+	def compute(self, image, kps, eps=1e-7):
+		# compute SIFT descriptors for OpenCV 2.4
+		if is_cv2:
+			(kps, descs) = self.extractor.compute(image, kps)
+
+		# otherwise, computer SIFT descriptors for OpenCV 3+
+		else:
+			(kps, descs) = self.extractor.detectAndCompute(image, None)
+
+		# if there are no keypoints or descriptors, return an empty tuple
+		if len(kps) == 0:
+			return ([], None)
+
+		# apply the Hellinger kernel by first L1-normalizing and taking the
+		# square-root
+		descs /= (descs.sum(axis=1, keepdims=True) + eps)
+		descs = np.sqrt(descs)
+
+		# return a tuple of the keypoints and descriptors
+		return (kps, descs)