def check_blank_image(file):
img = cv2.imread(file)
if img is None:
return False
# grary
img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
# threshold to two value image
ret,thresh = cv2.threshold(img, 150, 255,cv2.THRESH_BINARY)
# white %
nonzero = np.count_nonzero(thresh)
all = thresh.size
return (nonzero / float(all)) > 0.99
def check_blank_image(file):
img = cv2.imread(file)
if img is None:
return False
# grary
img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
# threshold to two value image
ret,thresh = cv2.threshold(img, 150, 255,cv2.THRESH_BINARY)
# white %
nonzero = np.count_nonzero(thresh)
all = thresh.size
return (nonzero / float(all)) > 0.99
def check_blank_image(file):
img = cv2.imread(file)
if img is None:
return False
# grary
img = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
# threshold to two value image
ret,thresh = cv2.threshold(img, 150, 255,cv2.THRESH_BINARY)
# white %
nonzero = np.count_nonzero(thresh)
all = thresh.size
return (nonzero / float(all)) > 0.99
解释下：先转灰度，再做二值化，然后判断白色占比。
上面的150是卡的阈值，超过150都认为是黑色设为255，小于的则认为是白色，这里要比50%的125偏黑一点，不然 字少的容易检测成白纸，卡的阀值99类似的道理。