Convert Python Opencv Image (numpy array) to PyQt QPixmap image

Question

I am trying to convert python opencv image to QPixmap.

I follow the instruction shows Page Link and my code is attached below

img = cv2.imread('test.png')[:,:,::1]/255. 
imgDown = cv2.pyrDown(img)
imgDown = np.float32(imgDown)        
cvRGBImg = cv2.cvtColor(imgDown, cv2.cv.CV_BGR2RGB)
qimg = QtGui.QImage(cvRGBImg.data,cvRGBImg.shape[1], cvRGBImg.shape[0], QtGui.QImage.Format_RGB888)
pixmap01 = QtGui.QPixmap.fromImage(qimg)
self.image01TopTxt = QtGui.QLabel('window',self)
self.imageLable01 = QtGui.QLabel(self)
self.imageLable01.setPixmap(pixmap01)

The code has no compile and runtime error but the conversion is wrong and I just get some noise image. I am not sure what the problem is. Could anyone help?

Answer 1

Use this to convert cvImage to Qimage, here cvImage is the original image.

height, width, channel = cvImg.shape
bytesPerLine = 3 * width
qImg = QImage(cvImg.data, width, height, bytesPerLine, QImage.Format_RGB888)

and set this Qimage to Label. setPixmap parameter from Qimage. It works!!!

Answer 2

Just complementing the answer of AdityaIntwala, if the image appears to be red or blue, it is because the format is not RGB, but BGR (the inverse). In this case, use the QImage.rgbSwapped method to correct:

height, width, channel = cvImg.shape
bytesPerLine = 3 * width
qImg = QImage(cvImg.data, width, height, bytesPerLine, QImage.Format_RGB888).rgbSwapped()

Answer 3

#image is the numpy array that you got from cv2.imread(example_image.jpg)

image = QtGui.QImage(image, image.shape[1],\
                            image.shape[0], image.shape[1] * 3,QtGui.QImage.Format_RGB888)
pix = QtGui.QPixmap(image)

self.scene.addPixmap(pix)

Answer 4

Hate to add to the large number of answers, but as this was the only thing that worked for me I will, in case others run into the same issue.

As mentioned here on GitHub

Wrap the numpy array/ndarry in a np.require(array, np.uint8, 'C') call first, such as:

arr2 = np.require(arr, np.uint8, 'C')
qImg = QtGui.QImage(arr2, width, height, QtGui.QImage.Format_RGB888)

Answer 5

Here's my take on this:

def convert_nparray_to_QPixmap(self,img):
    w,h,ch = img.shape
    # Convert resulting image to pixmap
    if img.ndim == 1:
        img =  cv2.cvtColor(img,cv2.COLOR_GRAY2RGB)

    qimg = QImage(img.data, h, w, 3*h, QImage.Format_RGB888) 
    qpixmap = QPixmap(qimg)

    return qpixmap

Answer 6

AdityaIntwala's answer was close but it didnt work for me. the cvImg.data gave an error like 'argument 1 has unexpected type 'memoryview'. So I have removed the 'cvImg.data' and passed the cvImg.tobytes() as bytes, and it worked

height, width, channel = cvImg.shape
bytesPerLine = 3 * width
qImg = QImage(cvImg.tobytes(), width, height, bytesPerLine, QImage.Format_RGB888).rgbSwapped()

then I have set the pixmap as shown below

self.imageLabel.setPixmap(QPixmap(qImg))

Answer 7

我建议使用软件包qimage2ndarray将numpy数组与Qimages相互转换。

Answer 8

There is the easiest way:

from PIL.ImageQt import ImageQt 
from PIL import Image
from PySide2.QtGui import QPixmap
import cv2


# Convert an opencv image to QPixmap
def convertCvImage2QtImage(cv_img):
    rgb_image = cv2.cvtColor(cv_img, cv2.COLOR_BGR2RGB)
    PIL_image = Image.fromarray(rgb_image).convert('RGB')
    return QPixmap.fromImage(ImageQt(PIL_image))

Answer 9

  image=cv2.imread("your_image.png")
  image = QtGui.QImage(image, image.shape[1],image.shape[0], image.shape[1] * 3, QtGui.QImage.Format_BGR888)
  pix = QtGui.QPixmap(image)
  self.image.setPixmap(QtGui.QPixmap(pix))