我们从Python开源项目中，提取了以下11个代码示例，用于说明如何使用cv2.isContourConvex()。
def find_squares(img): img = cv2.GaussianBlur(img, (5, 5), 0) squares = [] for gray in cv2.split(img): for thrs in xrange(0, 255, 26): if thrs == 0: bin = cv2.Canny(gray, 0, 50, apertureSize=5) bin = cv2.dilate(bin, None) else: retval, bin = cv2.threshold(gray, thrs, 255, cv2.THRESH_BINARY) bin, contours, hierarchy = cv2.findContours(bin, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) for cnt in contours: cnt_len = cv2.arcLength(cnt, True) cnt = cv2.approxPolyDP(cnt, 0.02 * cnt_len, True) if len(cnt) == 4 and cv2.contourArea(cnt) > 1000 and cv2.isContourConvex(cnt): cnt = cnt.reshape(-1, 2) max_cos = np.max([angle_cos(cnt[i], cnt[(i + 1) % 4], cnt[(i + 2) % 4]) for i in xrange(4)]) if max_cos < 0.1: squares.append(cnt) return squares
def find_squares(img): img = cv2.GaussianBlur(img, (5, 5), 0) squares = [] for gray in cv2.split(img): for thrs in xrange(0, 255, 26): if thrs == 0: bin = cv2.Canny(gray, 0, 50, apertureSize=5) bin = cv2.dilate(bin, None) else: _retval, bin = cv2.threshold(gray, thrs, 255, cv2.THRESH_BINARY) contours, _hierarchy = find_contours(bin, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) for cnt in contours: x, y, w, h = cv2.boundingRect(cnt) cnt_len = cv2.arcLength(cnt, True) cnt = cv2.approxPolyDP(cnt, 0.02*cnt_len, True) area = cv2.contourArea(cnt) if len(cnt) == 4 and 20 < area < 1000 and cv2.isContourConvex(cnt): cnt = cnt.reshape(-1, 2) max_cos = np.max([angle_cos( cnt[i], cnt[(i+1) % 4], cnt[(i+2) % 4] ) for i in xrange(4)]) if max_cos < 0.1: if (1 - (float(w) / float(h)) <= 0.07 and 1 - (float(h) / float(w)) <= 0.07): squares.append(cnt) return squares
def find_squares(img, cos_limit = 0.1): print('search for squares with threshold %f' % cos_limit) img = cv2.GaussianBlur(img, (5, 5), 0) squares = [] for gray in cv2.split(img): for thrs in xrange(0, 255, 26): if thrs == 0: bin = cv2.Canny(gray, 0, 50, apertureSize=5) bin = cv2.dilate(bin, None) else: retval, bin = cv2.threshold(gray, thrs, 255, cv2.THRESH_BINARY) bin, contours, hierarchy = cv2.findContours(bin, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) for cnt in contours: cnt_len = cv2.arcLength(cnt, True) cnt = cv2.approxPolyDP(cnt, 0.02*cnt_len, True) if len(cnt) == 4 and cv2.contourArea(cnt) > 1000 and cv2.isContourConvex(cnt): cnt = cnt.reshape(-1, 2) max_cos = np.max([angle_cos( cnt[i], cnt[(i+1) % 4], cnt[(i+2) % 4] ) for i in xrange(4)]) if max_cos < cos_limit : squares.append(cnt) else: #print('dropped a square with max_cos %f' % max_cos) pass return squares ### ### Version V2. Collect meta-data along the way, with commentary added. ###
def get_rectangles(contours): rectangles = [] for contour in contours: epsilon = 0.04*cv2.arcLength(contour,True) hull = cv2.convexHull(contour) approx = cv2.approxPolyDP(hull,epsilon,True) if (len(approx) == 4 and cv2.isContourConvex(approx)): rectangles.append(approx) return rectangles
def get_contours(image, polydb=0.1, contour_range=7): # find the contours in the edged image, keeping only the largest ones, and initialize the screen contour contours = _findContours(image, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) cnts = sorted(contours, key = cv2.contourArea, reverse = True)[:contour_range] # loop over the contours screenCnt = None for c in cnts: # approximate the contour peri = cv2.arcLength(c, True) #finds the Contour Perimeter approx = cv2.approxPolyDP(c, polydb * peri, True) # if our approximated contour has four points, then we can assume that we have found our screen if len(approx) == 4: screenCnt = approx break if screenCnt is None: raise EdgeNotFound() # sometimes the algorythm finds a strange non-convex shape. The shape conforms to the card but its not complete, so then just complete the shape into a convex form if not cv2.isContourConvex(screenCnt): screenCnt = cv2.convexHull(screenCnt) x,y,w,h = cv2.boundingRect(screenCnt) screenCnt = numpy.array([[[x, y]], [[x+w, y]], [[x+w, y+h]], [[x, y+h]]]) return screenCnt
def cannyThresholding(self, contour_retrieval_mode = cv2.RETR_LIST): ''' contour_retrieval_mode is passed through as second argument to cv2.findContours ''' # Attempt to match edges found in blue, green or red channels : collect all channel = 0 for gray in cv2.split(self.img): channel += 1 print('channel %d ' % channel) title = self.tgen.next('channel-%d' % channel) if self.show: ImageViewer(gray).show(window = title, destroy = self.destroy, info = self.info, thumbnailfn = title) found = {} for thrs in xrange(0, 255, 26): print('Using threshold %d' % thrs) if thrs == 0: print('First step') bin = cv2.Canny(gray, 0, 50, apertureSize=5) title = self.tgen.next('canny-%d' % channel) if self.show: ImageViewer(bin).show(window = title, destroy = self.destroy, info = self.info, thumbnailfn = title) bin = cv2.dilate(bin, None) title = self.tgen.next('canny-dilate-%d' % channel) if self.show: ImageViewer(bin).show(window = title, destroy = self.destroy, info = self.info, thumbnailfn = title) else: retval, bin = cv2.threshold(gray, thrs, 255, cv2.THRESH_BINARY) title = self.tgen.next('channel-%d-threshold-%d' % (channel, thrs)) if self.show: ImageViewer(bin).show(window='Next threshold (n to continue)', destroy = self.destroy, info = self.info, thumbnailfn = title) bin, contours, hierarchy = cv2.findContours(bin, contour_retrieval_mode, cv2.CHAIN_APPROX_SIMPLE) title = self.tgen.next('channel-%d-threshold-%d-contours' % (channel, thrs)) if self.show: ImageViewer(bin).show(window = title, destroy = self.destroy, info = self.info, thumbnailfn = title) if contour_retrieval_mode == cv2.RETR_LIST or contour_retrieval_mode == cv2.RETR_EXTERNAL: filteredContours = contours else: filteredContours = [] h = hierarchy[0] for component in zip(contours, h): currentContour = component[0] currentHierarchy = component[1] if currentHierarchy[3] < 0: # Found the outermost parent component filteredContours.append(currentContour) print('Contours filtered. Input %d Output %d' % (len(contours), len(filteredContours))) time.sleep(5) for cnt in filteredContours: cnt_len = cv2.arcLength(cnt, True) cnt = cv2.approxPolyDP(cnt, 0.02*cnt_len, True) cnt_len = len(cnt) cnt_area = cv2.contourArea(cnt) cnt_isConvex = cv2.isContourConvex(cnt) if cnt_len == 4 and (cnt_area > self.area_min and cnt_area < self.area_max) and cnt_isConvex: cnt = cnt.reshape(-1, 2) max_cos = np.max([angle_cos( cnt[i], cnt[(i+1) % 4], cnt[(i+2) % 4] ) for i in xrange(4)]) if max_cos < self.cos_limit : sq = Square(cnt, cnt_area, cnt_isConvex, max_cos) self.squares.append(sq) else: #print('dropped a square with max_cos %f' % max_cos) pass found[thrs] = len(self.squares) print('Found %d quadrilaterals with threshold %d' % (len(self.squares), thrs))
def get_contours(image, polydb=0.03, contour_range=5, show=False): # find the contours in the edged image, keeping only the largest ones, and initialize the screen contour # if cv2version == 3: im2, contours, hierarchy = cv2.findContours(image.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) contours = _findContours(image, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) cnts = sorted(contours, key = cv2.contourArea, reverse = True)[:contour_range] # loop over the contours screenCnt = None for c in cnts: # approximate the contour peri = cv2.arcLength(c, True) #finds the Contour Perimeter approx = cv2.approxPolyDP(c, polydb * peri, True) # if our approximated contour has four points, then we can assume that we have found our screen if len(approx) == 4: screenCnt = approx break if screenCnt is None: raise EdgeNotFound() # sometimes the algorythm finds a strange non-convex shape. The shape conforms to the card but its not complete, so then just complete the shape into a convex form if not cv2.isContourConvex(screenCnt): screenCnt = cv2.convexHull(screenCnt) x,y,w,h = cv2.boundingRect(screenCnt) screenCnt = np.array([[[x, y]], [[x+w, y]], [[x+w, y+h]], [[x, y+h]]]) if show: #this is for debugging puposes new_image = image.copy() cv2.drawContours(new_image, [screenCnt], -1, (255, 255, 0), 2) cv2.imshow("Contour1 image", new_image) cv2.waitKey(0) cv2.destroyAllWindows() return screenCnt
def get_contours(image, polydb=0.03, contour_range=5, show=False): # find the contours in the edged image, keeping only the largest ones, and initialize the screen contour if cv2version == 3: im2, contours, hierarchy = cv2.findContours(image.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) cnts = sorted(contours, key = cv2.contourArea, reverse = True)[:contour_range] # loop over the contours screenCnt = None for c in cnts: # approximate the contour peri = cv2.arcLength(c, True) #finds the Contour Perimeter approx = cv2.approxPolyDP(c, polydb * peri, True) # if our approximated contour has four points, then we can assume that we have found our screen if len(approx) == 4: screenCnt = approx break if screenCnt is None: raise EdgeNotFound() # sometimes the algorythm finds a strange non-convex shape. The shape conforms to the card but its not complete, so then just complete the shape into a convex form if not cv2.isContourConvex(screenCnt): screenCnt = cv2.convexHull(screenCnt) x,y,w,h = cv2.boundingRect(screenCnt) screenCnt = np.array([[[x, y]], [[x+w, y]], [[x+w, y+h]], [[x, y+h]]]) if show: #this is for debugging puposes new_image = image.copy() cv2.drawContours(new_image, [screenCnt], -1, (255, 255, 0), 2) cv2.imshow("Contour1 image", new_image) cv2.waitKey(0) cv2.destroyAllWindows() return screenCnt
def get_contours(image, polydb=0.1, contour_range=7, show=False): # find the contours in the edged image, keeping only the largest ones, and initialize the screen contour contours = _findContours(image, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) cnts = sorted(contours, key = cv2.contourArea, reverse = True)[:contour_range] # loop over the contours screenCnt = None for c in cnts: # approximate the contour peri = cv2.arcLength(c, True) #finds the Contour Perimeter approx = cv2.approxPolyDP(c, polydb * peri, True) # if our approximated contour has four points, then we can assume that we have found our screen if len(approx) == 4: screenCnt = approx break if screenCnt is None: raise EdgeNotFound() # sometimes the algorythm finds a strange non-convex shape. The shape conforms to the card but its not complete, so then just complete the shape into a convex form if not cv2.isContourConvex(screenCnt): screenCnt = cv2.convexHull(screenCnt) x,y,w,h = cv2.boundingRect(screenCnt) screenCnt = numpy.array([[[x, y]], [[x+w, y]], [[x+w, y+h]], [[x, y+h]]]) if show: #this is for debugging puposes new_image = image.copy() cv2.drawContours(new_image, [screenCnt], -1, (255, 255, 0), 2) cv2.imshow("Contour1 image", new_image) cv2.waitKey(0) cv2.destroyAllWindows() return screenCnt
def get_contours(image, polydb=0.03, contour_range=7, show=False): # find the contours in the edged image, keeping only the largest ones, and initialize the screen contour # if cv2version == 3: im2, contours, hierarchy = cv2.findContours(image.copy(), cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) contours = _findContours(image, cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE) cnts = sorted(contours, key = cv2.contourArea, reverse = True)[:contour_range] # loop over the contours screenCnt = None for c in cnts: # approximate the contour peri = cv2.arcLength(c, True) #finds the Contour Perimeter approx = cv2.approxPolyDP(c, polydb * peri, True) # if our approximated contour has four points, then we can assume that we have found our screen if len(approx) == 4: screenCnt = approx break if screenCnt is None: raise EdgeNotFound() # sometimes the algorythm finds a strange non-convex shape. The shape conforms to the card but its not complete, so then just complete the shape into a convex form if not cv2.isContourConvex(screenCnt): screenCnt = cv2.convexHull(screenCnt) x,y,w,h = cv2.boundingRect(screenCnt) screenCnt = numpy.array([[[x, y]], [[x+w, y]], [[x+w, y+h]], [[x, y+h]]]) if show: #this is for debugging puposes new_image = image.copy() cv2.drawContours(new_image, [screenCnt], -1, (255, 255, 0), 2) cv2.imshow("Contour1 image", new_image) cv2.waitKey(0) cv2.destroyAllWindows() return screenCnt
def main(): img = cv2.imread('../images/road.png') # convert to gray and to binary using a threshold, to detect edges/shapes gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY) ret, thresh = cv2.threshold(gray, 127, 255, 4) # find shapes/contours contours, h = cv2.findContours(thresh, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE) for contour in contours: perimeter = cv2.arcLength(contour, True) # skip shape/contour if it is too small or too big if perimeter < 50 or perimeter > 400 or cv2.isContourConvex(contour): continue approx = cv2.approxPolyDP(contour, 0.02 * cv2.arcLength(contour, True), True) x, y, w, h = cv2.boundingRect(contour) # colour different shapes if len(approx) == 3: cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2) elif len(approx) == 4: cv2.rectangle(img, (x, y), (x + w, y + h), (0, 0, 255), 2) elif len(approx) >= 100: cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 255), 2) else: # not an interesting shape for us continue # crop out the image, which might be a traffic sign, # save it to test.png cropped = img[y:y + h, x:x + w] cv2.imwrite('test.png', cropped) # query DIGITS REST API for classification response = requests.post( 'http://localhost:5000/models/images/classification/classify_one.json?job_id=20151207-223900-80d9', files={'image_file': ('file.png', open('test.png', 'rb'))}) predictions = response.json()['predictions'] # only label shape if over 90% if predictions[0][1] > 90: print predictions[0][0] cv2.putText(img, predictions[0][0], (x + w + 5, y + h + 5), cv2.FONT_HERSHEY_SIMPLEX, 0.5, 255) cv2.imshow('Demo', img) cv2.waitKey(0) cv2.destroyAllWindows()
