I have image data coming in from over a socket connection as a byte[]. All examples I have seen using cvLoadImage() is passed a file name. Do I have to save every image to file and re-open it to do the processing? This seems to have a lot of overhead for what needs to happen, is it possible to load the image from the byte[] data?
Simple solution in the end, you can use the following method to create an Image from a BufferedImage which solved my problem:
IplImage src = IplImage.createFrom(buffered);
Assuming the data is encoded in some standard format like JPG or PNG, and assuming you are using JavaCV, for a byte array b, this works as well:
IplImage image = cvDecodeImage(cvMat(1, b.length, CV_8UC1, new BytePointer(b)));
Related
Im trying to apply the code posted in this post:
How to convert from CMYK to RGB in Java correctly?
The Answer from the guy named Codo works for me so far, but my source is not a file, its an object that gets converted into a BufferedImage with
stream = (PRStream)object;
PdfImageObject image = new PdfImageObject(stream);
//this does not work
BufferedImage bi = image.getBufferedImage();
The guy has a method that returns a BufferedImage from a file like so
public BufferedImage readImage(File file) throws IOException, ImageReadException
but i want to use
BufferedImage bi = readImage(image.getBufferedImage());
instead of
File f = new File("/Users/adlib/Documents/projekte/pdf_compress/envirement/eclipse_luna/WORKSPACE/PDFCompression/src/Bild.jpg");
BufferedImage bi = readImage(f);
cause im ectracting all the images from a pdf file using iText.
I messed around with the code (changed file to BufferedImage and added streams) but a just dont get it to work. The File as Input image works fine, but not really what i need. What do i need to change to get This guys code to work with BufferedImage as input for the readImage() method?
Here is the complete code of this guy
https://stackoverflow.com/a/12132630/4944643
He uses Sanselan / Apache Commons Imaging
I'm not sure how iText extracts images, but chances are good it's using ImageIO. If so, you can just install (or depend on, using Maven) the TwelveMonkeys JPEG ImageIO plugin, and
BufferedImage bi = image.getBufferedImage();
...should just work.
The above mentioned plugin does support CMYK (and Adobe YCCK) JPEGs.
If iText doesn't use ImageIO, the above won't work (ie. when you already have a BufferedImage, it's too late to make the correct conversion). You will instead need to get to the bytes of the underlying PDF (using the getImageAsBytes() method), and use ImageIO (via the TwelveMonkeys JPEG plugin) to decode it:
byte[] imgBytes = image.getImageAsBytes();
BufferedImage bi = ImageIO.read(new ByteArrayInputStream(imgBytes));
I will modify and add Tiff-Tags to existing tif-files with java. JAI imageio crashed, because it could not deal with certain tags from Tiff 6.0. Apache Commons-Imaging seems to be able to deal with these tags. But I have no idea, how to do that. I found a post here, I used for beginning (How to embed ICC_Profile in TiffOutputSet).
Using the example code creates an image, which I can't open because of an LZW error. If I use the Imaging.writeImage(...) methods, It changes the color model from 8Bit to 24Bit and the Exif metadata hase gone.
What i have done is:
bufferedImage = Imaging.getBufferedImage(srcTiff);
byte[] imageBytes = Imaging.writeImageToBytes(tifFile, imageFormat, optional_params)
exifDirectory = tiffOutputSet.getOrCreateRootDirectory();
...
TiffImageWriterLossLess lossLessWriter = new TiffImageWriterLossless(imageBytes);
os = new FileOutputStream(tmpFile);
os = new BufferedOutputStream(os);
lossLessWriter.writeImage(bufferedImage, os, image_params);
Playing around with image_params, like compression or defining the outputset as params, results in different issues. But one is constant, the destImage is bigger then the src image, even when the source image is 24 bit like the dest image.
How could I get Commons-Imaging work for me?
I can respond to the destImage bigger than the src, it is because TIFF images have a compression that is not carried over when the image is read into memory. On writing the image back to storage, you must apply the compression explicitly.
I am working around my project and got some Problem, I searched for it , but couldn't find meaning full learning resource, What I need is to Store Image in SQL Server Database using my Java program , and will need that Back to Retrieve, images are not of larger size they are ranging between 30 and 50 K,
I can load images from my Disk by using getImage() method in toolKit
Image imm = Toolkit.getDefaultToolkit().getImage("URl");
, but i don't know How to convert that image to Binary Format and to store in Database, and then retrieve Back From Database.
I want to Store that in VarBinary s by looking around several sites i found that the image type in SQL Server is soon going to Retire.
While it's not a good idea to store very large binary objects in the database, the Microsoft research paper "To BLOB or Not To BLOB: Large Object Storage in a Database or a Filesystem" indicates it's an efficient approach if object sizes are less than 256K. So it sounds like you've hit the sweet spot for database storage with 30K images.
You can load your image as a buffered image from a URL using:
BufferedImage imm = ImageIO.read(url);
Then convert it to a byte array with:
byte[] immAsBytes =
ByteArrayOutputStream baos = new ByteArrayOutputStream();
//use another encoding if JPG is innappropriate for you
ImageIO.write(imm, "jpg", baos );
baos.flush();
byte[] immAsBytes = baos.toByteArray();
baos.close();
Then store the byte array as recommended by this article as a VARBINARY in the database. In your JDBC code, you should wrap the byte array in a ByteArrayInputStream and set the PreparedStatement parameter as a BinaryStream:
PreparedStatement pstmt = commection.prepareStatement("INSERT INTO IMAGES (image) VALUES(?)");
ByteArrayInputStream bais = new ByteArrayInputStream(immAsBytes);
pstmt.setBinaryStream(1, bais, immAsBytes.length);
pstmt.executeUpdate();
pstmt.close();
To get the image out of the database, use ResultStatement.getBlob():
Blob immAsBlob = rs.getBlob();
byte[] immAsBytes = immAsBlob.getBytes(1, (int)immAsBlob.length()));
Finally, convert the byte array to a BufferedImage and do something with it:
InputStream in = new ByteArrayInputStream(immAsBytes);
BufferedImage imgFromDb = ImageIO.read(in);
It is generally not a very good idea to put into the database large resources like images, unless you really need ACID compliance when working with them. Database dumps and time required to produce them grow tremendously and you will need to use the more complex and fragile incremental backups.
Generally it may be more efficient to store the images on the filesystem, and only put the image path to the database after you are sure the image resource has been successfully created.
I have a tiff image stored as Base64 encoded String in a file. My aim is to create a tiff file out of it. This is what I am doing:
String base64encodedTiff = IOUtils.toString(new FileInputStream("C:/tiff-attachment.txt"));
byte[] imgBytes = DatatypeConverter.parseBase64Binary(base64encodedTiff);
BufferedImage bufImg = ImageIO.read(new ByteArrayInputStream(imgBytes));
ImageIO.write(bufImg, "tiff", new File("c:/new-darksouls-imageIO-tiff.tiff"));
ImageIO.write() is throwing IllegalArgumentException because bufImg is null. I don't understand what am I doing wrong here.
On the contrary if I use IOUtils to write, it works fine:
IOUtils.write(imgBytes, new FileOutputStream("c:/new-darksouls-io-tiff.tiff"));
Please help me understand
Why ImageIO is throwing exception
What is the right API and way for what I am trying to achieve.
ImageIO would be useful if, for example, you wanted to convert a PNG to a JPEG. Since you don't need to manipulate the image or convert to another format, don't bother with ImageIO. Just use IOUtils.write() to save the TIFF data verbatim.
ImageIO.read() is returning a null image because it can't read the TIFF file, probably because TIFF isn't one of the standard ImageIO plugin formats. The standard supported image formats are listed here:
http://docs.oracle.com/javase/6/docs/api/javax/imageio/package-summary.html
An additional note -- the code you posted buffers the entire image in memory. If you're concerned about using memory efficiently, consider using some kind of Base64 decoding input stream to perform the decoding on the fly. That might look like this:
try (FileOutputStream out = new FileOutputStream("c:/new-darksouls-io-tiff.tiff");
FileInputStream in = new FileInputStream("C:/tiff-attachment.txt");
Base64InputStream decodedIn = new Base64InputStream(in)) {
IOUtils.copy(decodedIn, out);
}
I create a PIL image string on a python server:
frame = cv.CaptureFromCAM(0)
image = Image.fromstring('RGB', cv.GetSize(frame), frame.tostring(), 'raw', 'BGR')
buffer = cStringIO.stringIO()
image.save(buffer,'JPEG')
udptransmit(buffer.getvalue())
I have a java client trying to read the transmitted image string and reform the jpeg. This however doesn't seem to be working. I created a python client just to check, and I can reform the jpeg correctly using a call to pygame's load method.
The string being sent from python, contains characters 6:10 = JFIF, which is the correct format (also recognised by python's imghdr module.
In java, I ahve tried
simply writing the byte contents of the string received into a file and naming it with a .jpeg extension. The file isn't a valid jpeg.
Using ImageIO to read the bytes from the string. This produces a null image.
Tried to fetch ImageReaderByFormat('JPEG') and parse the bytes with this. This gives me an error stating 'Image is not a JPEG, starts with 0x...'
I really can't see why python recognises the string as a valid jpeg and java doesn't. Do the two use different jpeg decoders? Even if they do, shouldn't both either validate or reject the string?
Just found a solution to the problem
The problem was with the charset used in java while converting the string sent from my python server into bytes in java.
Here's the simple modification that was required in my java client code:
Charset charset = Charset.forName("ISO-8859-1");
Byte[] bytes: Array[Byte] = cam_data.getBytes(charset)
File f = new File("image.jpeg")
FileImageOutputStream fios = new FileImageOutputStream(f)
BufferedImage bim = ImageIO.read(new ByteArrayInputStream(bytes))
ImageIO.write(bim,"jpeg",fios)
The helpful link that lead me to the answer was http://www.java-forums.org/advanced-java/50516-reading-image-files-into-strings.html