在java中将像素值设置为灰度等级时，丢失图像部分

Question

i am doing work on images using java. i read a gray scale image and convert the pixel values to 0 and 1 i got the output image correctly for only some images. in others some image portions are lost here is the code i am using to make the image array back into image

`BufferedImage I = ImageIO.read(new File("path"));
 SampleModel sampleModel;
 Raster pixelData;
 pixelData = I.getData();
 int[][] pixels=new int[wid][hgt];
 sampleModel=pixelData.getSampleModel();



 BufferedImage image=new BufferedImage(wid,hgt,BufferedImage.TYPE_BYTE_BINARY);
 WritableRaster raster=Raster.createWritableRaster(sampleModel,new Point(0,0));
     for(int i=0;i<wid;i++)
     {
         for(int j=0;j<hgt;j++)
         {
            raster.setSample(i,j,0,pixels[i][j]);
         }
     }
     image.setData(raster);

File output=new File("path");
    ImageIO.write(image,"png",output);
 System.out.println("..End..");`

size of the image is same as original but the entire size contains only a portion of original image.can u help me

Answer 1

Your problem is probably related to the sample model you are using. The sample model is responsible to describe how the Raster is going to store the data, maybe you are using a model that puts more info per pixel and then the image gets only a part of the original buffer.

Cheers

[Update] @Joop Egen is correct you need to use the sample model from the image in which you defined that you are using a grayscale byte per pixel "configuration"

Answer 2

got a gud answer for my problem it worked well for all images(including 24 bit and 8 bit images)

 BufferedImage I = ImageIO.read(new File("path"));
 Raster pixelData;
 pixelData = I.getData();
 int pixels[][]=new int[wid][hgt];


     for ( x=0;x<wid;x++)
     {
         for( y=0;y<hgt;y++)
         {
             pixels[x][y]=pixelData.getSample(x,y,0);
          }  
     }


 BufferedImage image=new BufferedImage(wid,hgt,BufferedImage.TYPE_BYTE_BINARY);
 ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
 int[] nBits = { 8 };
 ColorModel cm = new ComponentColorModel(cs, nBits, false, true,Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
 SampleModel sm = cm.createCompatibleSampleModel(wid, hgt);
 WritableRaster raster=Raster.createWritableRaster(sm,new Point(0,0));
     for(int i=0;i<wid;i++)
     {
         for(int j1=0;j1<hgt;j1++)
         {
            raster.setSample(i,j1,0,pixels[i][j1]);
         }
     }
  image.setData(raster);
  File output=new File("path");
  ImageIO.write(image,"png",output);`