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Cannot cast DataBufferInt to DataBufferByte on specific picture(s)

I am trying to threshold my images, but some of them have problem with casting to DataBufferByte. I post here two types of pictures - the first (the test1.jpg is good and can be casted to DataBufferByte), the second (test2.jpg throwing an exception).
Images:
Here is my code:
public static void main(String[] args) throws IOException {
System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
BufferedImage bufferedImage = ImageIO.read(new File("/test/test2.jpg"));
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(bufferedImage, "jpg", byteArrayOutputStream);
byte[] input = byteArrayOutputStream.toByteArray();
InputStream is = new ByteArrayInputStream(input);
bufferedImage = ImageIO.read(is);
byte[] data = ((DataBufferByte) bufferedImage.getRaster().getDataBuffer()).getData();
Mat mat = new Mat(bufferedImage.getHeight(), bufferedImage.getWidth(), CvType.CV_8UC3);
mat.put(0, 0, data);
Mat mat1 = new Mat(bufferedImage.getHeight(),bufferedImage.getWidth(),CvType.CV_8UC1);
Imgproc.cvtColor(mat, mat1, Imgproc.COLOR_RGB2GRAY);
byte[] data1 = new byte[mat1.rows() * mat1.cols() * (int)(mat1.elemSize())];
mat1.get(0, 0, data1);
Mat dst = new Mat();
Imgproc.adaptiveThreshold(mat1, dst, 255, Imgproc.ADAPTIVE_THRESH_MEAN_C, Imgproc.THRESH_BINARY, 11, 15);
MatOfByte matOfByte = new MatOfByte();
Imgcodecs.imencode(".jpg", dst, matOfByte);
ByteArrayInputStream inputStream = new ByteArrayInputStream(matOfByte.toArray());
bufferedImage = ImageIO.read(inputStream);
ImageIO.write(bufferedImage, "jpg", new File("/test_output/test2.jpg"));
}
The output for test1.jpg image is correct:
But the second image throwing an exception
Exception in thread "main" java.lang.ClassCastException:
java.awt.image.DataBufferInt cannot be cast to
java.awt.image.DataBufferByte
at line
byte[] data = ((DataBufferByte) bufferedImage.getRaster().getDataBuffer()).getData();
What is the problem ? Why the one .jpg image is converted without problems but second throwing an exception?

Both are not of the same format. One using 8-bit for color representation and the other 3x8-bit (so 4 bytes, with padding or transparency)?
Looking at it give:
image1 : JPEG image data, JFIF standard 1.01, aspect ratio, density 1x1, segment length 16, baseline, precision 8, 449x361, components 3
image2 : PNG image data, 617 x 353, 8-bit/color RGBA, non-interlaced
You may use the getDataType() method on the buffer to get the size of the color representation.

How can I convert fingerprint jpg to WSQ use JMRTD WSQEncoder.encode

I'm using JMRTD library (https://github.com/E3V3A/JMRTD/tree/master/wsq_imageio) to encode jpg to WSQ. I set Bitmap by manually instead of decode from WSQ file.
BufferedImage bufferedImage = ImageIO.read(fileInput.getInputStream());
WritableRaster raster = bufferedImage.getRaster();
DataBufferByte data = (DataBufferByte) raster.getDataBuffer();
Bitmap bitmap = new Bitmap(data.getData(), width, height, ppi, depth, lossyflag);
OutputStream outputStream = new FileOutputStream("c.wsq");
String commentText = "";
WSQEncoder.encode(outputStream, bitmap, bitrate, commentText);
Here is my original picture jpg:
And below is my result WSQ file:
How can I fix it. Many thanks!

I resolved this problem, here is my code for convert jpg, png to wsq format:
// 1. Read files to BufferedImage for get width, height. Convert Bit depth to 8-gray
BufferedImage bufferedImage = ImageIO.read(fileInput.getInputStream());
// 2. Convert Bit depth to 8-gray (This is what i had to do to solve this problem)
BufferedImage img = new BufferedImage(bufferedImage.getWidth(), bufferedImage.getHeight(), BufferedImage.TYPE_BYTE_GRAY);
Graphics g = img.getGraphics();
g.drawImage(bufferedImage, 0, 0, null);
g.dispose();
// 3. Convert file format to byte[] and convert to type Bitmap
WritableRaster raster = img.getRaster();
DataBufferByte data = (DataBufferByte) raster.getDataBuffer();
Bitmap bitmap = new Bitmap(data.getData(), bufferedImage.getWidth(), bufferedImage.getHeight(), 500, 8, 1);
// 4. Create file wsq
OutputStream outputStream = new FileOutputStream("c.wsq");
double bitrate = 0.75f;
String commentText = "";
// 5. Write the input file to the generated wsq file
WSQEncoder.encode(outputStream, bitmap, bitrate, commentText);
outputStream.close();
Hope help you # Dan Ortega

compress transparent png image to jpg give black background java

compress transparent png image to jpg give black background
I want white background instead of black
public static byte[] getBitMapBytes(Bitmap bmp, int quality) {
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, quality, stream);
byte[] byteArray = stream.toByteArray();
return byteArray;
}
fos = new FileOutputStream(f);
fos.write(getBitMapBytes(compressedImage, 60));

Got the answer :
Bitmap newBitmap = Bitmap.createBitmap(image.getWidth(),
image.getHeight(), image.getConfig());
Canvas canvas = new Canvas(newBitmap);
canvas.drawColor(Color.WHITE);
Rect dest = new Rect(0, 0, image.width, image.height);
Rect src = new Rect(0, 0, image.width, image.height);
canvas.drawBitmap(bmp, src, dest, null);

This is a normal behavior. Jpeg doesn't manage transparency.
You can use this kind of lib if you just want to reduce the size of the image:
http://objectplanet.com/pngencoder/ or online https://tinypng.com/

RGB to HSV conversion

I'm very new to Android and Opencv, I would like to convert some rgb image to hsv and I know I can use
Imgproc.cvtColor(mat, mat1, Imgproc.COLOR_RGB2HSV);
But how do I create the "mat" in android ?
In Java I used:
byte[] data = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
Mat mat = new Mat(image.getHeight(), image.getWidth(), CvType.CV_8UC3);
mat.put(0, 0, data);
In Android I already got this:
mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.pic1);
mPhotoWidth = mBitmap.getWidth();
mPhotoHeight = mBitmap.getHeight();
Thanks,

b is your Bitmap image.
Mat tmp = new Mat (b.getWidth(), b.getHeight(), CvType.CV_8UC3);
Utils.bitmapToMat(b, tmp);
Imgproc.cvtColor(tmp, tmp, Imgproc.COLOR_RGB2HSV);
// back to Bitmap
Utils.matToBitmap(tmp, b);

8 bit gray scale image byte array to jpg

I am trying to convert a 8 bit gray scale image byte array to jpg image format in java.
static byte[] bytes = new byte[]{126, 126, 127, -128};
public static void main(String[] args) throws IOException {
ByteArrayInputStream bis = new ByteArrayInputStream(bytes);
Iterator<?> readers = ImageIO.getImageReadersByFormatName("jpg");
ImageReader reader = (ImageReader) readers.next();
Object source = bis;
ImageInputStream iis = ImageIO.createImageInputStream(source);
reader.setInput(iis, true);
ImageReadParam param = reader.getDefaultReadParam();
Image image = reader.read(0, param);
BufferedImage bufferedImage = new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_BYTE_GRAY);
Graphics2D g2 = bufferedImage.createGraphics();
g2.drawImage(image, null, null);
File imageFile = new File("C:\\newrose3.jpg");
ImageIO.write(bufferedImage, "jpg", imageFile);
System.out.println(imageFile.getPath());
}
I have bytes having image data and I want to convert it into readable image format in java.

Assuming bytes is supposed to be pixel data, you should create an image from those bytes, then write it out as JPEG.
Something like:
// Create an image type grayscale
BufferedImage image = new BufferedImage(2, 2, BufferedImage.TYPE_BYTE_GRAY);
// Get the backing pixels, and copy into it
byte[] data = ((DataBufferByte) image.getRaster().getDataBuffer()).getData();
System.arraycopy(bytes, 0, data, 0, bytes.length);
// Write it out:
ImageIO.write(image, "jpg", new File("yourPathHere");