OpenCV (Open Source Computer Vision Library) is an open source computer vision and machine learning software library. OpenCV was built to provide a common infrastructure for computer vision applications and to accelerate the use of machine perception in the commercial products.
Being a BSD-licensed product, OpenCV makes it easy for businesses to utilize and modify the code.
To use the camera to find the frame face
video_capture = cv2.VideoCapture(0) process_this_frame = True while True: # Grab a single frame of video ret, frame = video_capture.read() # Resize frame of video to 1/4 size for faster face recognition processing small_frame = cv2.resize(frame, (0, 0), fx=0.25, fy=0.25) # Convert the image from BGR color (which OpenCV uses) to RGB color (which face_recognition uses) rgb_small_frame = small_frame[:, :, ::-1] # Only process every other frame of video to save time if process_this_frame: # Find all the faces and face encodings in the current frame of video f_face_locations = face_recognition.face_locations(rgb_small_frame) f_face_encodings = face_recognition.face_encodings( rgb_small_frame, f_face_locations) # print(f_face_encodings) for f_face_encoding in f_face_encodings: match = face_recognition.compare_faces(face_encodings, f_face_encoding, 0.4) print(match) for (i, name) in enumerate(face_correct_names): if match[i]: print(face_correct_names[i]) process_this_frame = not process_this_frame cv2.imshow('Video2', frame) # Hit 'q' on the keyboard to quit! if cv2.waitKey(1) & 0xFF == ord('q'): break video_capture.release() cv2.destroyAllWindows()
Load and Display an Image
Then create a Mat object that will store the data of the loaded image.
First argument is filename
Second argument specifies the format:
- IMREAD_UNCHANGED (<0) loads the image as is (including the alpha channel if present)
- IMREAD_GRAYSCALE ( 0) loads the image as an intensity one
- IMREAD_COLOR (>0) loads the image in the RGB format
Modify and Save an Image
cvtColor( image, gray_image, COLOR_BGR2GRAY );
imwrite( "../../images/Gray_Image.jpg", gray_image );
Save your transformed image in a file on disk (using
Write the Mat gray_image to a new file.
How OpenCV stores and handles images?
- Mat is that you no longer need to manually allocate its memory and release it as soon as you do not need it
uchar* cv::Mat::ptr(int i): Returns a pointer to the specified matrix row.