Python OpenCV 类型错误：预期的 Ptr<cv::umat> 对于参数“lowerb”和颜色问题</cv::umat>

Question

Disclaimer: I'm a beginner in OpenCv, so there is a possibility of existence of very simple mistakes So I've prepared a code that counts pixels in given boundaries, and then save sit's count in an array, to make it possible to calculate pcc using them.

def PCCprepare():
    print("[LOG] reporting!")
    tot_pixel = 0
    pixels = []
    old_b = 0
    old_g = 0

    dir = os.listdir("res")
    for filename in dir:
        i = 0
        img = cv2.imread("res/" + filename)

        output = cv2.bitwise_and(img, img)
        tot_pixel += output.size
        for b in range(4):
            for g in range(4):
                for r in range(4):
                    lower = [b * 63.75, g * 63.75, r * 63.75]
                    print(lower)
                    if b > old_b:
                        upper = ([(b + 1) * 63.75, g * 63.75, r * 63.75])
                    elif g > old_g:
                        upper = ([b * 63.75, (g + 1) * 63.75, r * 63.75])
                    else:
                        upper = ([b * 63.75, g * 63.75, (r + 1) * 63.75])
                    print(upper)
                    old_g = g
                    old_b = b

                    mask = cv2.inRange(img, lower, upper)
                    output = cv2.bitwise_and(img, img, mask=mask)

                    try:
                        pixels[i] += np.count_nonzero(output)
                    except:
                        pixels.append(np.count_nonzero(output))
                    i += 1

It used to work for fixed bounderies, but as for now it always gives back the following exception:

Ignoring exception in command imgSetup:
Traceback (most recent call last):
  File "C:\Users\user\Downloads\Mash_The_CharacterCreator\venv\lib\site-packages\discord\ext\commands\core.py", line 85, in wrapped
    ret = await coro(*args, **kwargs)
  File "C:/Users/user/Downloads/Mash_The_CharacterCreator/bot.py", line 727, in waifuSet
    await ctx.send("<@!" + str(ctx.message.author.id) + "> " + imgWorks.PCCprepare())
  File "C:\Users\user\Downloads\Mash_The_CharacterCreator\WaifuMeterPNG.py", line 53, in PCCprepare
    mask = cv2.inRange(img, lower, upper)
TypeError: Expected Ptr<cv::UMat> for argument 'lowerb'

Also if there is anyone who could help me with boundareis, cause I wold like to count every possible colour, and previously I used sth like this

lower = [b * 63.75, g * 63.75, r * 63.75]
print(lower)
upper = [(b + 1) * 63.75, (g + 1) * 63.75, (r + 1) * 63.75]
print(upper)

but it leads to overlapping and inaccurate boundaries, so I would be glad if anyone more familiar with this topic would suggest some better solution for them

Answer 1

In Python, the lowerb and upperb parameters of function cv2.inRange(src, lowerb, upperb, dst) does not accept lists, it only support tuples. So instead of using brackets, simply change them to parentheses:

lower = (b * 63.75, g * 63.75, r * 63.75)

I have tested your code with the updated lower and upper variables on my machine and it works.