Qt图像处理技术七:轮廓提取

Qt图像处理技术七:轮廓提取

效果图

原理

图像先二值化让rgb数值相同，只有(0,0,0)或者(255,255,255)

取每个点的周围8个点，如果周围8个点与该点rgb值相同，则需要将该点描黑为(255,255,255)

代码

QImage ContourExtraction(const QImage &img)
{
    int width = img.width();
    int height = img.height();
    int pixel[8];
    QImage binImg = Binaryzation(img);
    QImage newImg = QImage(width, height, QImage::Format_RGB888);
    newImg.fill(Qt::white);

    uint8_t *rgb = newImg.bits();
    uint8_t *binrgb = binImg.bits();
    int nRowBytes = (width * 24 + 31) / 32 * 4;
    int  lineNum_24 = 0;
    for (int y = 1; y < height - 1; y++) {
        for (int x = 1; x < width - 1; x++) {
            memset(pixel, 0, 8);
            lineNum_24 = y * nRowBytes;
            if (binrgb[lineNum_24 + x * 3] == 0) {
                rgb[lineNum_24 + x * 3] = 0;
                rgb[lineNum_24 + x * 3 + 1] = 0;
                rgb[lineNum_24 + x * 3 + 2] = 0;
                pixel[0] = binrgb[(y - 1) * nRowBytes + (x - 1) * 3];
                pixel[1] = binrgb[(y) * nRowBytes + (x - 1) * 3];
                pixel[2] = binrgb[(y + 1) * nRowBytes + (x - 1) * 3];
                pixel[3] = binrgb[(y - 1) * nRowBytes + (x) * 3];
                pixel[4] = binrgb[(y + 1) * nRowBytes + (x) * 3];
                pixel[5] = binrgb[(y - 1) * nRowBytes + (x + 1) * 3];
                pixel[6] = binrgb[(y) * nRowBytes + (x + 1) * 3];
                pixel[7] = binrgb[(y + 1) * nRowBytes + (x + 1) * 3];

                if (pixel[0] + pixel[1] + pixel[2] + pixel[3] + pixel[4] + pixel[5] + pixel[6] + pixel[7] == 0) {
                    rgb[lineNum_24 + x * 3] = 255;
                    rgb[lineNum_24 + x * 3 + 1] = 255;
                    rgb[lineNum_24 + x * 3 + 2] = 255;
                }

            }
        }
    }
    return newImg;
}