I need to do conformance tests of JPEG decoder. The streams available in ITUS are .j2k for jpeg2000 format. What is the standard used in .jpg format? How do they differ in structure? How can I view the J2k files?
JPEG 2000 is a completely different file format from JPEG (which is usually what .jpg files are). The Wikipedia article I linked gives a list of compatible software.
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How to convert image.png or image.bmp to integer array? (do not use any non-standard library)
Please ignore chunks that are not directly related to image data.(IHDR、IEND...etc.)
thank you very much.
SOLVED: I should use binary I/O function in stdio.h to read image file. thanks
If you have to read images into arrays without any image processing libraries you need two things:
You need means to read files in general.
You need to know the internal structure of the file formats you want to read.
So for png refer to https://www.w3.org/TR/2003/REC-PNG-20031110/
This document will tell you where to find the image dimensions, pixel data and other features. It's basically a manual for software developers on how to use this standard format properly.
Some image formats will require additional work like decrompression.
I have a winodws 8 Laptop. If I put tags in my jpegs, can I use these tags to search jpeg files on other windows / linux machines? Or I have to use specific application to do so.
For some background. JPEG does not define a file format. There are a number of file formats that have been defined for JPEG images. JFIF, SPIFF, ADOBE, and EXIF are examples of such formats.
The JPEG standard defines APP0-APPF (hex) markers for applications to store metadata. Their structure is not defined by JPEG. The various file formats use some of these markers. The rest can be used by applications.
The EXIF format defines various tags that you can use with that format.
JFIF does not have tags but has some limited metadata.
The answer then is that the various file formats allow the storage of metadata either within their own structures, tags, or unreserved APPn markers.
The problem you face is that the applications need to be able to read the metadata that you write.
Tags are supported by the JPEG format. Windows 8 supports the standard. You will be able to use these tags on other Windows and Linux machines.
For more information, you can see this post: http://beckustech.wordpress.com/2013/03/12/tagging-jpeg-image-files/
I have a folder of image file which have been compressed into .dat file. Since the .dat files are extremly huge(They are the microscopic image of the organ.), I don't really know what kind of tools that I can use to convert it into jpeg file. So the best case would that the whole image is split up into pieces, and I can get all the pieces of the image.
The ".dat" file suffix is used broadly, so you'll need to specify more details on what format/source software created the original data. As a guess, from a quick search of ".dat" format microscopy, these tools looks like they might be applicable to your domain:
http://gwyddion.net/
or
http://www.openmicroscopy.org/site/products/bio-formats
If you can't find a library for the format/languages you are using, then you'll need to find documentation of the file format, and write a converter (at least, the reading portion of the converter - you can use something like libjpeg to handle the writing portion.)
I have a collection of images in the CBM file format.
What is this format? How to read it? How to convert it to, say, a BMP bitmap?
Searching the net, I found that it could mean one of those three things:
1) Fuzzy Bitmap, as per Michael Mauldin's library, FBM (1989). The softwares XnView and Graphics Convert Pro 2011 should be able to open it, but they don't. Most likely it means that the file I have is not really a Fuzzy Bitmap.
2) Compiled bitmap, as per XLib (wikipedia)
How to proceed in order to test that my file is such a Compiled Bitmap? Where to download XLib / what should I build?
3) Compressed Bitmap. Do you have more info's on this format?
I found CreateDIBitmap function. If you pass correct parameters, you should be able to save it into some more known file format.
Here you can find something about Bitmap Compression.
If you don't know image details like resolution, bitsperpixel, compression type,... It will be hard to read it.
I believe CBMs are just Zip files renamed. Try renaming and unzipping.
try to open it with konvertor (www.konvertor.net); it does read several CBMs formats
I am aiming to combine multiple PDF files each with identical dimensions into one file.
I've seen how it is done with CGPDFContext. I am just curious if there are (better?) alternatives to this method on the Mac.
Let's say I have the option to use PDFs, TIFF, PNG or JPEG files as input. Would using a different input file type mean anything significant for the process, or it would be easier to go with PDF input?
I have use PDFDocument API and it is programmatically easier to use. It may need PDF files as input though.