mat.dump()的OpenCV Java Impartaiton返回数据不正确

Question

我正在寻找将图像像素数据提取到整数列表(或任何数字表示(中。例如，具有2 x 2的白色图像，结果将为[255,255,255,255]。如果图像是代码生成的，并且未读取磁盘：

    Mat m = new Mat(5, 10, CvType.CV_8UC1, new Scalar(0));
    System.out.println("OpenCV Mat: " + m);
    Mat mr1 = m.row(1);
    mr1.setTo(new Scalar(1));
    Mat mc5 = m.col(5);
    mc5.setTo(new Scalar(5));
    System.out.println("OpenCV Mat data, "+m.total()+" elements:n" + 
    m.dump());

准确打印=>

    OpenCV Mat: Mat [ 5*10*CV_8UC1, isCont=true, isSubmat=false, 
    nativeObj=0x1415d50, dataAddr=0x13a6880 ]
    OpenCV Mat data, 50 elements:
    [  0,   0,   0,   0,   0,   5,   0,   0,   0,   0;
       1,   1,   1,   1,   1,   5,   1,   1,   1,   1;
       0,   0,   0,   0,   0,   5,   0,   0,   0,   0;
       0,   0,   0,   0,   0,   5,   0,   0,   0,   0;
       0,   0,   0,   0,   0,   5,   0,   0,   0,   0]

但是，如果我在磁盘上写下垫子" m"内容，然后我再次阅读，dump((方法吐出奇怪的输出：

    Imgcodecs.imwrite(TRAIN_PATH_PROC+"m.jpg",m);
    m = null;
    m = Imgcodecs.imread(TRAIN_PATH_PROC+"m.jpg");
    System.out.println("Fresly read m, "+m.total()+" elements:n"+m.dump());

打印

Fresly read m, 50 elements:
[  0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   1,   1,   0,   0,   0,   
5,   5,   5,   1,   1,   1,   0,   0,   0,   0,   0,   0,   0,   0,   0;
1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   
5,   5,   5,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1,   1;
0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   1,   1,   0,   0,   0,   5,   
5,   5,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0;
0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   4,   
4,   4,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0;
0,   0,   0,   0,   0,   0,   0,   0,   0,   1,   1,   1,   0,   0,   0,   
5,   5,   5,   1,   1,   1,   0,   0,   0,   0,   0,   0,   0,   0,   0]

由于我需要从读取映像中提取int值，并依靠dump((用于字符串表示，这会使我麻烦。

编辑：

我只是使用

来提取数据

    List<Integer> values = new ArrayList<>();
    for (int i = 0; i < m.rows(); i++) {
        for (int j = 0; j < m.cols(); j++) {
            values.add((int)m.get(i,j)[0]);
        }
    }

Answer 1

mat.dump((是我们的朋友，正在打印垫子名称以揭示其属性。(应将问题标题更改为不贬低转储((。(IMREAD自动假设转换为BGR，因此数据的3个通道而不是预期的1个通道。IMWRITE JPEG会自动压缩。您可以控制IMREAD转换并减少压缩，但仍然有些失去。

MatOfInt imwrite_flags = new MatOfInt();
imwrite_flags.fromArray(Imgcodecs.IMWRITE_JPEG_QUALITY , 100);
Imgcodecs.imwrite(TRAIN_PATH_PROC+"m.jpg",m, imwrite_flags);
m = Imgcodecs.imread(TRAIN_PATH_PROC+"m.jpg", Imgcodecs.IMREAD_UNCHANGED);

您需要的是无或无损压缩，因此请使用TIFF格式 - 以下tiff的示例。(请参阅在OpenCV中保存TIFF文件时设置特定压缩方案的方法？(

String TRAIN_PATH_PROC = "";
Mat m = new Mat(5, 10, CvType.CV_8UC1, new Scalar(0));
System.out.println("OpenCV Mat: " + m);
Mat mr1 = m.row(1);
mr1.setTo(new Scalar(1));
Mat mc5 = m.col(5);
mc5.setTo(new Scalar(5));
System.out.println("OpenCV Mat data, "+m.total()+" elements:n" + 
m.dump());
MatOfInt imwrite_flags = new MatOfInt();
imwrite_flags.fromArray(Imgcodecs.IMWRITE_TIFF_COMPRESSION , 1); // no compression
Imgcodecs.imwrite(TRAIN_PATH_PROC+"m2.tif",m, imwrite_flags);// note name change so both examples can run
// OR
Imgcodecs.imwrite(TRAIN_PATH_PROC+"m.tif",m); // default compression LZW grayscale but lossless, I think
m = null;
m = Imgcodecs.imread(TRAIN_PATH_PROC+"m.tif", Imgcodecs.IMREAD_UNCHANGED);
System.out.println("OpenCV Mat: " + m);
System.out.println("Fresly read m, "+m.total()+" elements:n"+m.dump());