CODEWITHSUNDEEP
pythonopencvpython-imaging-libraryimread
anoold
anoold

Reputation: 103

Using cv2.imread: "<built-in function imread> returned NULL without setting an error", as if it can't open the picture or get the data

This is the part of my code that gives the problem. It is supposed to count the amount of green pixels in a picture:

img = Image.open('path.tif')

BLACK_MIN = np.array([0, 20, 20], np.uint8)

BLACK_MAX = np.array([120, 255, 255], np.uint8)

imgg = cv2.imread(img, 1)

dst = cv2.inRange(imgg, BLACK_MIN, BLACK_MAX)

no_black = cv2.countNonZero(dst)

print('The number of black pixels is: ' + str(no_black))

Upvotes: 10

Views: 36842

Answers (2)

Kukesh
Kukesh

Reputation: 520

Image is already readed using PIL.Now the img is in array format so you cannot able to read it again.Read your file in any one kind of format either pil or cv2

BLACK_MIN = np.array([0, 20, 20], np.uint8)

BLACK_MAX = np.array([120, 255, 255], np.uint8)

imgg = cv2.imread('path.tif', 1)

dst = cv2.inRange(imgg, BLACK_MIN, BLACK_MAX)

no_black = cv2.countNonZero(dst)

print('The number of black pixels is: ' + str(no_black))

Upvotes: -1

Blue Three Wheeler
Blue Three Wheeler

Reputation: 179

You are passing a PIL image to imread but it expects a filepath (https://docs.opencv.org/2.4/modules/highgui/doc/reading_and_writing_images_and_video.html?highlight=imread#Mat%20imread(const%20string&%20filename,%20int%20flags)

You should use:

imgg = cv2.imread('path.tif', 1)

Upvotes: 7

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