java - opencv java修改像素值

Question

我一直在尝试在 opencv java 中转换一些 opencv C++ 代码，但我似乎无法让像素划分正常工作。我采用均值转换分段垫，将其转换为灰度，然后转换为 32F。

然后我将先降采样后升采样的图像(由灰色均值漂移垫组成)与原始灰色均值漂移垫进行比较。

我已经读过 Using get() and put() to access pixel values in OpenCV for Java

但是，它和其他类似的东西不起作用。我收到的错误消息是无效的垫类型 5。但是，即使我能够看到显着图，我也肯定它是错误的。这是因为当我在 C++ 中传递图像 001.jpg 时，我应该看到原始图像 + 对象周围的红色方 block 。在 java 中，我只能在最后看到原始图像。

注意:

AbstractImageProvider.deepCopy(AbstractImageProvider.matToBufferedImage(显着性),disp);

是一个 API 调用，在我尝试显示原始垫子、meanShift 垫子和灰色 meanShift 垫子时起作用。它无法显示显着性。

C++

我只进行了 channel 拆分，因为我正在测试其他色彩空间，但是在 Java 中我只想使用灰度。

  input = MeanShift.clone();
  input.convertTo(input, CV_32F);

  for(int i = 0; i < Pyramid_Size; i++){DS_Pyramid[i] = input.clone();}

  for (int i = 0; i < Pyramid_Size; i++){ 
    for (int k = 0; k <= i; k++){ // Why don't I just downsamplex3 a copy of MeanShift.clone then upsamplex3 that same one? ...
      pyrDown (DS_Pyramid[i], DS_Pyramid[i], Size(DS_Pyramid[i].cols/2, DS_Pyramid[i].rows/2));
      US_Pyramid[i] = DS_Pyramid[i].clone();
    }
    for (int j = 0; j <= i; j++){
      pyrUp (US_Pyramid[i], US_Pyramid[i], Size(US_Pyramid[i].cols*2, US_Pyramid[i].rows*2));
    }
  }

  top = US_Pyramid[Pyramid_Size - 1].clone(); // most down sampled layer, up sampled.
  split(top, top_chs);
  split(input.clone(), meanShift_chs); // split into channels result
  split(input.clone(), sal_chs); // holder to use for compare

  float top_min = 1.0;
  float ms_min = 1.0;
  for (int i = 0; i < top.rows; i++){   // find the smallest value in both top and meanShift
    for (int k = 0; k < top.cols; k++){ // this is so you can sub out the 0 with the min value
      for (int j = 0; j < top.channels(); j++){ // later on
    float a = top_chs[j].at<float>(i,k);
    float b = meanShift_chs[j].at<float>(i,k);
    if (a < top_min && a >= 0) {top_min = a;} // make sure you don't have a top_min of zero... that'd be bad.
    if (b < ms_min && b >= 0)  { ms_min = b;}
      }
    }
  }

  for (int i = 0; i < top.rows; i++){
    for (int k = 0; k < top.cols; k++){
      for (int j = 0; j < top.channels(); j++){
    float a,b,c;
    a = top_chs[j].at<float>(i,k);
    b = meanShift_chs[j].at<float>(i,k);

    if (a <= 0){a = top_min;} // make sure you don't divide by zero
    if (b <= 0){b = ms_min;} // make sure you really don't divide by zero
    if (a <= b){c = 1.0 - a/b;}
    else {c = 1.0 - b/a;}

    // c = sqrt(c); // makes stuff more salient, but makes noise pop out too
    sal_chs[j].at<float>(i,k) = c;
      }
    }
  }
  merge(sal_chs, Saliency); // combine into saliency map
  imshow("saliency", Saliency);

Java

    MeanShift = inputImage.clone();

    Imgproc.pyrMeanShiftFiltering(MeanShift, MeanShift, MeanShift_spatialRad, MeanShift_colorRad);
    Imgproc.cvtColor(MeanShift, MeanShift, Imgproc.COLOR_BGR2GRAY);

    MeanShift.convertTo(MeanShift, CvType.CV_32F);                 // 32F between 0 - 1. ************** IMPORTANT LINE

    for (int i = 0; i < PyrSize; i++){
        DS_Pyramid.add(new Mat());
        UP_Pyramid.add(new Mat());
    }

    for (int i = 0; i < PyrSize; i++){    
        DS_Pyramid.set(i, MeanShift);
    }       

    for (int i = 0; i < PyrSize; i++){
        for(int k = 0; k <= i; k++){                               // At 0 is downsampled once, second twice, third 3 times. 
        Imgproc.pyrDown(DS_Pyramid.get(i), DS_Pyramid.get(i)); // pyrDown by default img.width / 2 img height / 2
        Mat a = new Mat();                                     // save the sampled down at i
        a = DS_Pyramid.get(i);                            
        UP_Pyramid.add(a);
        }
        for (int j = 0; j <= i; j++){
        Imgproc.pyrUp(UP_Pyramid.get(i),UP_Pyramid.get(i));    
        }                                                          
    }
    top = UP_Pyramid.get(PyrSize-1);
    bot = MeanShift.clone();
    Saliency = MeanShift.clone();


    //http://answers.opencv.org/question/5/how-to-get-and-modify-the-pixel-of-mat-in-java/
    //http://www.tutorialspoint.com/java_dip/applying_weighted_average_filter.htm

    for (int i = 0; i < top.rows(); i++){
        for (int j = 0; j < top.cols(); j++){
        int index = i * top.rows() + j;

        float[] top_temp = top.get(i, j);
        float[] bot_temp  = bot.get(i,j);
        float[] sal_temp = bot.get(i,j);

        if (top_temp[0] <= bot_temp[k]){sal_temp[0] = 1.0f - (top_temp[0]/bot_temp[0]);}
        else                           {sal_temp[0] = 1.0f - (bot_temp[0]/top_temp[0]);}

        Saliency.put(i,j, sal_temp);
        }
    }

    AbstractImageProvider.deepCopy(AbstractImageProvider.matToBufferedImage(Saliency),disp);

Answer 1

经过大量搜索，找到了一个简单且有效的解决方案。这可能会帮助您克服错误 - invalid mat type 5

代码:

Mat img = Highgui.imread("Input.jpg"); //Reads image from the file system and puts into matrix
int rows = img.rows(); //Calculates number of rows
int cols = img.cols(); //Calculates number of columns
int ch = img.channels(); //Calculates number of channels (Grayscale: 1, RGB: 3, etc.)

for (int i=0; i<rows; i++)
{
    for (int j=0; j<cols; j++)
    {
        double[] data = img.get(i, j); //Stores element in an array
        for (int k = 0; k < ch; k++) //Runs for the available number of channels
        {
            data[k] = data[k] * 2; //Pixel modification done here
        }
        img.put(i, j, data); //Puts element back into matrix
    }
}
Highgui.imwrite("Output.jpg", img); //Writes image back to the file system using values of the modified matrix

注意: 在线上任何地方都没有提到的重要一点是方法 put 不会将像素写入 Input.jpg。它只是更新矩阵 img 的值。因此，上面的代码不会改变输入图像中的任何内容。为了产生可见的输出，需要将矩阵 img 写入文件，即本例中的 Output.jpg。此外，使用 img.get(i, j) 似乎是处理矩阵元素的更好方法，而不是使用上面接受的解决方案，因为这有助于更好地可视化和使用图像矩阵方式并且不需要大的连续内存分配。