Question :
Disclaimer: huge openCV noob
Traceback (most recent call last):
File “lanes2.py”, line 22, in
canny = canny(lane_image)File “lanes2.py”, line 5, in canny
gray = cv2.cvtColor(imgUMat, cv2.COLOR_RGB2GRAY)TypeError: Expected cv::UMat for argument ‘src’
What exactly is ‘src’ referring to?
Answer #1:
src is the first argument to cv2.cvtColor.
The error you are getting is because it is not the right form. cv2.Umat() is functionally equivalent to np.float32(), so your last line of code should read:
gray = cv2.cvtColor(np.float32(imgUMat), cv2.COLOR_RGB2GRAY)
Answer #2:
gray = cv2.cvtColor(cv2.UMat(imgUMat), cv2.COLOR_RGB2GRAY)
UMat is a part of the Transparent API (TAPI) than help to write one code for the CPU and OpenCL implementations.
Answer #3:
The following can be used from numpy:
import numpy as np
image = np.array(image)
Answer #4:
Not your code is the problem this is perfectly fine:
gray = cv2.cvtColor(imgUMat, cv2.COLOR_RGB2GRAY)
The problem is that imgUMat is None so you probably made a mistake when loading your image:
imgUMat = cv2.imread("your_image.jpg")
I suspect you just entered the wrong image path.
Answer #5:
Is canny your own function? Do you use Canny from OpenCV inside it? If yes check if you feed suitable argument for Canny – first Canny argument should meet following criteria:
- type:
<type 'numpy.ndarray'> - dtype:
dtype('uint8') - being single channel or simplyfing: grayscale, that is 2D array, i.e. its
shapeshould be 2-tupleofints (tuplecontaining exactly 2 integers)
You can check it by printing respectively
type(variable_name)
variable_name.dtype
variable_name.shape
Replace variable_name with name of variable you feed as first argument to Canny.
Answer #6:
This is a general error, which throws sometimes, when you have mismatch between the types of the data you use. E.g I tried to resize the image with opencv, it gave the same error. Here is a discussion about it.
Answer #7:
Just add this at start:
image = cv2.imread(image)
Answer #8:
Some dtype are not supported by specific OpenCV functions. For example inputs of dtype np.uint32 create this error. Try to convert the input to a supported dtype (e.g. np.int32 or np.float32)
