Unable to apply otsu thresholding on gpu, opencv throws this: errorthreshold.cu:105: error: (-215:Assertion failed) type <= 4 in function 'threshold'

Question

I'm trying to do all my image processing in the GPU and not cpu processing:

# coding=utf8
import cv2

# Leer la imagen en la GPU
image = cv2.cuda_GpuMat()
image.upload(cv2.imread("sutil.jpeg"))
original = image


# Convertir la imagen de BGR a HSV en la GPU
image = cv2.cuda.cvtColor(image, cv2.COLOR_BGR2HSV)

# Convertir la imagen a escala de grises en la GPU
image = cv2.cuda.cvtColor(image, cv2.COLOR_BGR2GRAY)


# Binarizar la imagen en escala de grises con el método de Otsu en la GPU
ret, otsu = cv2.cuda.threshold(image,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)

# Aplicar una máscara binaria a la imagen original del limón en la GPU
result = cv2.cuda.bitwise_and(original, original, mask=otsu)

# Mostrar la imagen resultante segmentada
cv2.imshow('Imágen Resultante Segmentada',image)
cv2.waitKey(0)

However after apply the HSV conversion, the next step is apply otsu thresholding, and it is throwing this error:

Traceback (most recent call last):
  File "gpu.py", line 18, in <module>
    ret, otsu = cv2.cuda.threshold(image,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)
cv2.error: OpenCV(4.5.4) /home/orin/opencv_contrib/modules/cudaarithm/src/cuda/threshold.cu:105: error: (-215:Assertion failed) type <= 4 in function 'threshold'

what does mean it "type <= 4 in function 'threshold'" I don't know why this happens, my code on cpu works perfectly:

import cv2

image = cv2.imread("sutil.jpeg")
original = image

image = cv2.blur(image,(31,31),0)

# Convert BGR a HSV para saturar la imágen.

image = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)

#convertir a escala de grises (CV_RGB2GRAY)
image = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)

#Binarizar la imagen en escala de grises con el método de Otsu.
ret, otsu = cv2.threshold(image,0,255,cv2.THRESH_BINARY+cv2.THRESH_OTSU)

#Aplicar mascara binaria a la imagen original del limón.
result = cv2.bitwise_and(original, original, mask=otsu)

cv2.imshow('Imagen Resultante Segmentada', result)
cv2.waitKey(0)

also a detail in my gpu code version is that I removed "cv2.blur(image,(31,31),0)" because I can't do it, if you any idea guys to fix this two problems I will appreciate it.

thanks so much.

Answer 1

Documentation states:

The THRESH_OTSU and THRESH_TRIANGLE threshold types are not supported.