OpenCV TypeError: Expected cv::UMat for argument 'src' - What is this?
PythonOpencvTypeerrorSrcPython Problem Overview
Disclaimer: huge openCV noob
> Traceback (most recent call last):
>
> File "lanes2.py", line 22, in
What exactly is 'src' referring to?
Python Solutions
Solution 1 - Python
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)
Solution 2 - Python
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.
Solution 3 - Python
The following can be used from numpy:
import numpy as np
image = np.array(image)
Solution 4 - Python
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.
Solution 5 - Python
Just add this at start:
image = cv2.imread(image)
Solution 6 - Python
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.
Solution 7 - Python
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.
Solution 8 - Python
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)
Solution 9 - Python
Convert your image matrix to ascontiguousarray using np.ascontiguousarray as bellow:
gray = cv2.cvtColor(np.ascontiguousarray(imgUMat), cv2.COLOR_RGB2GRAY)
Solution 10 - Python
that is referring to the expected dtype of your image
"image".astype('float32') should solve your issue
Solution 11 - Python
Sometimes I have this error when videostream from imutils package doesn't recognize frame or give an empty frame. In that case, solution will be figuring out why you have such a bad frame or use a standard VideoCapture(0) method from opencv2
Solution 12 - Python
I got round thid by writing/reading to a file. I guessed cv.imread would put it into the format it needed. This code for anki Vector SDK program but you get the idea.
tmpImage = robot.camera.latest_image.raw_image.save('temp.png')
pilImage = cv.imread('temp.png')
Solution 13 - Python
If using ImageGrab
Verify that your image is not a 0x0 area due to an incorrect bbox.
Solution 14 - Python
If you are using byte object instead of reading from file you can convert your image to numpy array like this
image = numpy.array(Image.open(io.BytesIO(image_bytes)))
Solution 15 - Python
Verify the application root folder is the same as the file you are attempting to run.