CODEWITHSUNDEEP
pythonopencvimage-processing
Santi Peñate-Vera
Santi Peñate-Vera

Reputation: 1186

Grayscale image segmentation

I'm trying to segment a grayscale picture generated from field measurements, that is why it is not a conventional 3-channel picture.

I have tried this piece of code:

import cv2 #this is the openCV library
import numpy as np

# some code to generate img

ret,thresh = cv2.threshold(img ,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)

And it spits out this error:

cv2.error: ..\..\..\modules\imgproc\src\thresh.cpp:719: error: (-215) src.type() == CV_8UC1 in function cv::threshold

I have no idea on how to solve this since the usage seems to be pretty straight forward, so any idea is welcome.

Upvotes: 0

Views: 1403

Answers (2)

Santi Peñate-Vera
Santi Peñate-Vera

Reputation: 1186

So indeed the problem is the image type, since it contains double values thay need to be normalized to 0 ~ 255.

in my case 1000 is the maximum value possible

img = cv2.convertScaleAbs(img / 1000.0 * 255)

This worked for me.

Upvotes: 0

Alexey
Alexey

Reputation: 5978

The error is due to the following assert statement CV_Assert( src.type() == CV_8UC1 ); in thresh.cpp, meaning your input image is not of type CV_8UC1.

So make sure that your generated input image img is in fact CV_8UC1 (one channel 8-bit image).

Upvotes: 3

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