Question

我正在尝试使用OpenCV从磁盘加载.jpg或.png图像，并将其显示在我的GUI中的QLable中。我做了所有调整大小和从BGR转换为RGB的东西。有时我会得到一个完美的结果：

有时我会得到垃圾：

以下是此示例的代码：

from PyQt4.QtGui import QApplication, QWidget, QVBoxLayout, QImage, QPixmap, QLabel, QPushButton, QFileDialog
import cv2

app = QApplication([])
window = QWidget()
layout = QVBoxLayout(window)
window.setLayout(layout)
display = QLabel()
display.setMinimumSize(600, 400)
layout.addWidget(display)
button = QPushButton('Load', window)
layout.addWidget(button)


def read_image():
    path = QFileDialog.getOpenFileName(window)
    if path:
        picture = cv2.imread(path)
        if picture is not None:
            scaling_factor = min(display.width()/picture.shape[1], display.height()/picture.shape[0])
            width = round(picture.shape[1] * scaling_factor)
            height = round(picture.shape[0] * scaling_factor)
            picture = cv2.resize(picture, (width, height))
            print(path, scaling_factor, picture.shape)
            image = QImage(picture.tobytes(),  # The content of the image
                           picture.shape[1],  # The width (number of columns)
                           picture.shape[0],  # The height (number of rows)
                           QImage.Format_RGB888)  # The image is stored in 3*8-bit format
            display.setPixmap(QPixmap.fromImage(image.rgbSwapped()))
        else:
            display.setPixmap(QPixmap())

button.clicked.connect(read_image)
window.show()

app.exec()

Answer 1

我认为问题在于图像的大小和调整大小的图像的大小。如果图片的大小不能被（宽、高）整除，图片将无法正确显示。我也有类似的问题here。OpenCV的step是size_t，当你把图片转成QImage的时候需要转成int。

image = QImage(picture.tobytes(),  # The content of the image
                       picture.shape[1],  # The width (number of columns)
                       picture.shape[0],  # The height (number of rows)
                       static_cast<int>(picture.step), # cast width step to int
                       QImage.Format_RGB888)  # The image is stored in 3*8-bit format

OpenCV中调整大小的图像无法在Qt4（PyQt4）中正确显示

1 个答案: