Question

protected IplImage processImage(byte[] data, int width, int height) {
    int f = 4;// SUBSAMPLING_FACTOR;

    // First, downsample our image and convert it into a grayscale IplImage
    IplImage grayImage = IplImage.create(width / f, height / f, IPL_DEPTH_8U, 1);

    int imageWidth = grayImage.width();
    int imageHeight = grayImage.height();
    int dataStride = f * width;
    int imageStride = grayImage.widthStep();
    ByteBuffer imageBuffer = grayImage.getByteBuffer();
    for (int y = 0; y < imageHeight; y++) {
        int dataLine = y * dataStride;
        int imageLine = y * imageStride;
        for (int x = 0; x < imageWidth; x++) {
            imageBuffer.put(imageLine + x, data[dataLine + f * x]);
        }
    }

    return grayImage;
}

I should get an IplImage from onPreviewFrame(byte[] data, Camera camera).
In the way i wrote up there i get an iplimage much smaller than the original one.
There is any way to keep the same dimension on the new iplimage? Whould i avoid the subsampling factor? how can i do that?

Answer 1

Yes just put set f = 1 and it won’t subsample.