Qt图像处理技术三:图片亮度与对比度处理

Qt图像处理技术三:图片亮度和对比度处理

github地址

实战应用项目:
github :https://github.com/dependon/simple-image-filter //纯qt图像处理项目

效果图

公式

value都是取0-300
red=0.01对比值red-150+曝光值；
green=0.01对比值green-150+曝光值；
blue=0.01对比值blue-150+曝光值；

代码（容易理解）

QImage lightContrastImage(const QImage &img,  int light, int Contrast)
{
    QImage imgCopy = QImage(img);

    for (int y = 0; y < img.height(); y++) {
        for (int x = 0; x < img.width(); x++) {
            float r = light * 0.01 * qRed(img.pixel(x, y)) - 150 + Contrast;
            float g = light * 0.01 * qGreen(img.pixel(x, y)) - 150 + Contrast;
            float b = light * 0.01 * qBlue(img.pixel(x, y)) - 150 + Contrast;
            r = Bound(0, r, 255);
            g = Bound(0, g, 255);
            b = Bound(0, b, 255);
            imgCopy.setPixel(x, y, qRgb(r, g, b));
        }

    }
    return imgCopy;
}

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 QImageAPI::lightContrastImage(const QImage &img,  int light, int Contrast)
{
    QImage imgCopy;
    if (img.format() != QImage::Format_RGB888) {
        imgCopy = QImage(img).convertToFormat(QImage::Format_RGB888);
    } else {
        imgCopy = QImage(img);
    }
    uint8_t *rgb = imgCopy.bits();
    if (nullptr == rgb) {
        return QImage();
    }
    int r;
    int g;
    int b;
    int size = img.width() * img.height();
    for (int i = 0; i < size ; i++) {
        r = light * 0.01 * rgb[i * 3] - 150 + Contrast;
        g = light * 0.01 * rgb[i * 3 + 1] - 150 + Contrast;
        b = light * 0.01 * rgb[i * 3 + 2]  - 150 + Contrast;
        r = Bound(0, r, 255);
        g = Bound(0, g, 255);
        b = Bound(0, b, 255);
        rgb[i * 3] = r;
        rgb[i * 3 + 1] = g;
        rgb[i * 3 + 2] = b;
    }

    return imgCopy;
}

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liuminghang0821@qq.com
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