使用Python中的OpenCV从图像中裁剪面

我正在尝试从图像裁剪面部.

无论图像中有多少面,我都希望代码能够工作.

输入图像的示例：
Image with faces

我想裁剪面部,以便我可以对它们运行面部关键点检测算法(之前制作).

最终结果将如下所示：
Image after facial keypoint detection

我的代码目前是：

# Load in color image for face detection
image = cv2.imread('images/obamas4.jpg')

# Convert the image to RGB colorspace
image = cv2.cvtColor(image, cv2.COLOR_BGR2RGB)

# Make a copy of the original image to draw face detections on
image_copy = np.copy(image)

# Convert the image to gray 
gray_image = cv2.cvtColor(image, cv2.COLOR_RGB2GRAY)

# Detect faces in the image using pre-trained face dectector
faces = face_cascade.detectMultiScale(gray_image, 1.25, 6)

# Print number of faces found
print('Number of faces detected:', len(faces))

# Get the bounding box for each detected face
for f in faces:
    x, y, w, h = [ v for v in f ]
    cv2.rectangle(image_copy, (x,y), (x+w, y+h), (255,0,0), 3)
    # Define the region of interest in the image  
    face_crop = gray_image[y:y+h, x:x+w]

# Display the image with the bounding boxes
fig = plt.figure(figsize = (9,9))
axl = fig.add_subplot(111)
axl.set_xticks([])
axl.set_yticks([])

ax1.set_title("Obamas with Face Detection")
axl.imshow(image_copy)

# Display the face crops
fig = plt.figure(figsize = (9,9))
axl = fig.add_subplot(111)
axl.set_xticks([])
axl.set_yticks([])

axl.set_title("Obamas Face Crops")
axl.imshow(face_crop)

输出如下所示：
enter image description here

现在它只输出图像中检测到的最后一张脸.我确定我错过了像for循环一样简单的东西.

我希望能够在所有灰色裁剪的脸部图像上运行我的面部关键点检测算法.

谢谢您的帮助！

解决方法:

问题出在你的代码中,face_crop只存储检测到的最后一个面.

所以把它作为一个列表并附加所有面.然后使用for循环显示所有面.像这样：

face_crop = []
for f in faces:
    x, y, w, h = [ v for v in f ]
    cv2.rectangle(image_copy, (x,y), (x+w, y+h), (255,0,0), 3)
    # Define the region of interest in the image  
    face_crop.append(gray_image[y:y+h, x:x+w])

for face in face_crop:
    cv2.imshow('face',face)
    cv2.waitKey(0)

我使用cv2.imshow()来显示图像.您可以修改它以使用plt.imshow()

希望这可以帮助！

标签：python,opencv,computer-vision,face-detection
来源： https://codeday.me/bug/20190627/1305085.html