在android中的onPreviewFrame期间转换YUV-> RGB(图像处理)-> YUV? [英] Converting YUV->RGB(Image processing)->YUV during onPreviewFrame in android?

问题描述

我正在使用 SurfaceView 捕获图像并在 public void onPreviewFrame4(byte[] data, Camera camera)

I am capturing image using SurfaceView and getting Yuv Raw preview data in public void onPreviewFrame4(byte[] data, Camera camera)

我必须在 onPreviewFrame 中执行一些图像预处理，所以我需要将 Yuv 预览数据转换为 RGB 数据而不是图像预处理并返回到 Yuv 数据.

I have to perform some image preprocessing in onPreviewFrame so i need to convert Yuv preview data to RGB data than image preprocessing and back to Yuv data.

我使用这两个函数将 Yuv 数据编码和解码为 RGB，如下所示:

I have used both function for encoding and decoding Yuv data to RGB as following :

public void onPreviewFrame(byte[] data, Camera camera) {
    Point cameraResolution = configManager.getCameraResolution();
    if (data != null) {
        Log.i("DEBUG", "data Not Null");

                // Preprocessing
                Log.i("DEBUG", "Try For Image Processing");
                Camera.Parameters mParameters = camera.getParameters();
                Size mSize = mParameters.getPreviewSize();
                int mWidth = mSize.width;
                int mHeight = mSize.height;
                int[] mIntArray = new int[mWidth * mHeight];

                // Decode Yuv data to integer array
                decodeYUV420SP(mIntArray, data, mWidth, mHeight);

                // Converting int mIntArray to Bitmap and 
                // than image preprocessing 
                // and back to mIntArray.

                // Encode intArray to Yuv data
                encodeYUV420SP(data, mIntArray, mWidth, mHeight);
                    }
}

    static public void decodeYUV420SP(int[] rgba, byte[] yuv420sp, int width,
        int height) {
    final int frameSize = width * height;

    for (int j = 0, yp = 0; j < height; j++) {
        int uvp = frameSize + (j >> 1) * width, u = 0, v = 0;
        for (int i = 0; i < width; i++, yp++) {
            int y = (0xff & ((int) yuv420sp[yp])) - 16;
            if (y < 0)
                y = 0;
            if ((i & 1) == 0) {
                v = (0xff & yuv420sp[uvp++]) - 128;
                u = (0xff & yuv420sp[uvp++]) - 128;
            }

            int y1192 = 1192 * y;
            int r = (y1192 + 1634 * v);
            int g = (y1192 - 833 * v - 400 * u);
            int b = (y1192 + 2066 * u);

            if (r < 0)
                r = 0;
            else if (r > 262143)
                r = 262143;
            if (g < 0)
                g = 0;
            else if (g > 262143)
                g = 262143;
            if (b < 0)
                b = 0;
            else if (b > 262143)
                b = 262143;

            // rgb[yp] = 0xff000000 | ((r << 6) & 0xff0000) | ((g >> 2) &
            // 0xff00) | ((b >> 10) & 0xff);
            // rgba, divide 2^10 ( >> 10)
            rgba[yp] = ((r << 14) & 0xff000000) | ((g << 6) & 0xff0000)
                    | ((b >> 2) | 0xff00);
        }
    }
}


    static public void encodeYUV420SP_original(byte[] yuv420sp, int[] rgba,
        int width, int height) {
    final int frameSize = width * height;

    int[] U, V;
    U = new int[frameSize];
    V = new int[frameSize];

    final int uvwidth = width / 2;

    int r, g, b, y, u, v;
    for (int j = 0; j < height; j++) {
        int index = width * j;
        for (int i = 0; i < width; i++) {
            r = (rgba[index] & 0xff000000) >> 24;
            g = (rgba[index] & 0xff0000) >> 16;
            b = (rgba[index] & 0xff00) >> 8;

            // rgb to yuv
            y = (66 * r + 129 * g + 25 * b + 128) >> 8 + 16;
            u = (-38 * r - 74 * g + 112 * b + 128) >> 8 + 128;
            v = (112 * r - 94 * g - 18 * b + 128) >> 8 + 128;

            // clip y
            yuv420sp[index++] = (byte) ((y < 0) ? 0 : ((y > 255) ? 255 : y));
            U[index] = u;
            V[index++] = v;
        }
    }

问题是编码和解码 Yuv 数据可能有一些错误，因为如果我跳过预处理步骤，那么编码的 Yuv 数据与 PreviewCallback 的原始数据不同.

The problem is that encoding and decoding Yuv data might have some mistake because if i skip the preprocessing step than also encoded Yuv data are differ from original data of PreviewCallback.

请帮我解决这个问题.我必须在 OCR 扫描中使用此代码，因此我需要实现这种类型的逻辑.

Please help me to resolve this issue. I have to used this code in OCR scanning so i need to implement this type of logic.

如果有任何其他方式做同样的事情，请提供给我.

If any other way of doing same thing than please provide me.

提前致谢.:)

推荐答案

为什么不指定相机预览应提供 RGB 图像?

Why not specify that camera preview should provide RGB images?

即Camera.Parameters.setPreviewFormat(ImageFormat.RGB_565);

这篇关于在android中的onPreviewFrame期间转换YUV-> RGB(图像处理)-> YUV?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！