def showImage(self,pixmap):
        self.scene = QtWidgets.QGraphicsScene()
        self.scene.addPixmap(pixmap)
        self.graphicsView_2.setScene(self.scene)
        self.graphicsView_2.fitInView(self.scene.itemsBoundingRect())

    def grayscale(self):
        image = self.imageName
        buffer = QtCore.QBuffer()
        buffer.open(QtCore.QBuffer.ReadWrite)
        image.save(buffer, "JPG")
        pil_im = Image.open(io.BytesIO(buffer.data()))
        im = pil_im.convert('RGB')
        matrix = (0.2, 0.5, 0.3, 0.0, 0.2, 0.5, 0.3, 0.0, 0.2, 0.5, 0.3, 0.0)
        result = im.convert('RGB',matrix)
        self.showImage(self.pil2pixmap(result))