图像阈值不适用于拉普拉斯图像

Question

I need to perform a thresholded zero-crossing detection of the filtered image's laplacian. But once the laplacian is applied, it gives error when doing thresholding. Any advice?

code:

img = cv2.imread('H:/FYP/interim/aniso.jpg')
lap = cv2.Laplacian(img, 1, ksize=5)
retval, threshold = cv2.threshold(lap, 70, 255, cv2.THRESH_BINARY)
plt.imshow(threshold)

error:

---------------------------------------------------------------------------
error                                     Traceback (most recent call last)
<ipython-input-23-e36300501b24> in <module>
      1 img = cv2.imread('H:/FYP/interim/aniso.jpg')
      2 lap = cv2.Laplacian(img, 1, ksize=5)
----> 3 retval, threshold = cv2.threshold(lap, 70, 255, cv2.THRESH_BINARY)
      4 plt.imshow(threshold)

error: OpenCV(4.1.0) C:\projects\opencv-python\opencv\modules\imgproc\src\thresh.cpp:1612: error: (-210:Unsupported format or combination of formats)  in function 'cv::threshold'

Answer 1

you can change like this

retval, threshold = cv2.threshold(img, 127, 255, cv2.THRESH_TOZERO)