ImageItem crashing after a minute of displaying frames from camera

Question

I have a PyQtGraph widget that I am using to display processed arrays from a framegrabber. A thread acquires these puts these data into a queue and another thread gets these data from the queue and calls update(data) on my widget. Data is a relatively small (400*100) numpy array

class BScanView(PyQtG.GraphicsLayoutWidget):

    def __init__(self, aspect=0.5):
        super().__init__()
        self.aspect = aspect

        self.viewbox = self.addViewBox(row=1,col=1)
        self.viewbox.setAspectLocked()
        self.image = PyQtG.ImageItem()
        self.viewbox.addItem(self.image)

    def update(self, data):
        self.image.clear()
        self.image.setImage(data, autoLevels=False, levels=(-100, -2))
        QtGui.QGuiApplication.processEvents()

This works for awhile but randomly crashes the ImageItem. The rest of the GUI works fine for subsequent use but the above widget is unresponsive.

Answer 1

It's difficult to say because I cannot reproduce your issue but I can think of a few potential causes.

1. Perhaps the underlying data buffer of the data array is shared between the threads and updated incorrectly. Try making a copy of the array before you set it in the image with self.image.setImage(np.copy(data),...
2. The GraphicsLayoutWidget is a decendent of QWidget and therefore has an update method. You override it with a different signature. I don't know PyQt handles this exactly but try renaming your method to updateImage and see if it makes a difference.
3. Why are you using processEvents? You should not need it here.

Your code example is not an MVCE in the sense that it's not complete; information is missing on how the data is created in the other thread. Hundred percent completeness is not always achievable (external libraries and such), but try to make it as complete as possible. To make a complete, minimal and verifiable example can be a fair amount of work, but the more effort you put into it, the more answers you will receive and the better they will be.