Currently using Windows 10 with Python 3.7 I tried running with this code in order to get the webcam to function for use in number recognition
def get_img_contour_thresh(img):
x, y, w, h = 0, 0, 300, 300
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray, (5, 5), 0)
ret, thresh1 = cv2.threshold(blur, 175, 255, cv2.THRESH_BINARY_INV +
cv2.THRESH_OTSU)
thresh1 = thresh1[y:y + h, x:x + w]
contours, hierarchy = cv2.findContours(thresh1, cv2.RETR_TREE,
cv2.CHAIN_APPROX_SIMPLE)[-2:]
return img, contours, thresh1
def show_webcam(mirror=False):
# load json and create model
json_file = open('model.json', 'r')
loaded_model_json = json_file.read()
json_file.close()
model = model_from_json(loaded_model_json)
# load weights into new model
model.load_weights("model.h5")
print("Loaded model from disk")
model.compile(loss='categorical_crossentropy',
optimizer='adam',
metrics=['accuracy'])
cap = cv2.VideoCapture(0)
while True:
ret, img = cap.read()
img, contours, thresh = get_img_contour_thresh(img)
ans = ''
if len(contours) > 0:
contour = max(contours, key=cv2.contourArea)
if cv2.contourArea(contour) > 500:
x, y, w, h = cv2.boundingRect(contour)
newImage = thresh[y:y + h, x:x + w]
newImage = cv2.resize(newImage, (28, 28))
newImage = np.array(newImage)
newImage = newImage.astype('float32')
newImage /= 255
if K.image_data_format() == 'channels_first':
newImage = newImage.reshape(1, 28, 28)
else:
newImage = newImage.reshape(28, 28, 1)
newImage = np.expand_dims(newImage, axis=0)
ans = model.predict(newImage).argmax()
x, y, w, h = 0, 0, 300, 300
cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2)
cv2.putText(img, "CNN : " + str(ans), (10, 320),
cv2.FONT_HERSHEY_SIMPLEX, 0.7, (0, 0, 255), 2)
cv2.imshow("Frame", img)
cv2.imshow("Contours", thresh)
if cv2.waitKey(1) & 0xFF == ord('q'):
break
cap.release()
cv2.destroyAllWindows()
def main():
show_webcam(mirror=True)
if __name__ == '__main__':
main()
I receive this error
File "cam.py", line 75, in <module>
main()
File "cam.py", line 71, in main
show_webcam(mirror=True)
File "cam.py", line 34, in show_webcam
img, contours, thresh = get_img_contour_thresh(img)
File "cam.py", line 10, in get_img_contour_thresh
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
cv2.error: OpenCV(3.4.4) C:\projects\opencv-
python\opencv\modules\imgproc\src\color.cpp:181: error: (-215:Assertion
failed) !_src.empty() in function 'cv::cvtColor'
Iv been looking for a solution for a while but havent had any luck in figuring this out, tried looking around but just cant figure it out, what do you guys think? Appreciate the help given
The error you're seeing is one that happens if None gets passed on cv2.cvtColor.
After
ret, img = cap.read()
it's a good idea to check that img is not None before proceeding. Depending on your input source, cap.read() can fail. One one my laptops, it fails at least once before starting to return valid images.
来源：https://stackoverflow.com/questions/54121013/open-cv-error-215assertion-failed-src-empty-in-function-cvcvtcolor