Qt图像处理技术四:图像二值化

Qt图像处理技术四:图像二值化

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实战应用项目:
github :https://github.com/dependon/simple-image-filter //纯qt图像处理项目（包括多种滤镜）

效果

原理

rgb
每一点取rgb的平均值,
当平均值>128,设置点为255,255,255
当平均值<128,设置点为0,0,0

源码(容易理解版)

QImage Binaryzation(const QImage &origin)
{
    int width = origin.width();
    int height = origin.height();
    QImage newImg = QImage(width, height, QImage::Format_RGB888);

    for (int x = 0; x < width; x++) {
        for (int y = 0; y < height; y++) {
            int gray = qGray(origin.pixel(x, y));
            int newGray;
            if (gray > 128)
                newGray = 255;
            else
                newGray = 0;
            newImg.setPixel(x, y, qRgb(newGray, newGray, newGray));
        }
    }
    return newImg;
}

源码(相对上述源码快5-20倍，因为绕过了Qt每个取点的检测)

QImage Binaryzation(const QImage &img)
{
    QImage imgCopy;

    if (img.format() != QImage::Format_RGB888) {
        imgCopy = QImage(img).convertToFormat(QImage::Format_RGB888);
    } else {
        imgCopy = QImage(img);
    }
    uint8_t *rgb = imgCopy.bits();
    int newGray = 0;
    int gray = 0;
    int size = img.width() * img.height();
    for (int i = 0; i < size ; i++) {
        gray = (rgb[i * 3] + rgb[i * 3 + 1] + rgb[i * 3 + 2]) / 3;
        if (gray > 128)
            newGray = 255;
        else
            newGray = 0;
        rgb[i * 3] = newGray;
        rgb[i * 3 + 1] = newGray;
        rgb[i * 3 + 2] = newGray;
    }
    return imgCopy;
}