Programming with JPX Features

JPX is a wavelet-based image compression standard that defines the JPX file format and is part of the JPEG 2000 standard. It uses a hierarchical format to store several resolutions of the image in the same file without duplication. Consequently, a JPX compressed image can be sent to a device in the best resolution for that device, without requiring additional overhead storage. The standardized filename extension for the format is .jpx (JPEG 2000 Part2, conforming to standard ISO/IEC 15444-2).

In comparison to the standard JPEG format, the JPX file format provides greater flexibility and better image quality, especially at the higher compressions.

JPX (JPEG 2000 Part 2) Features

The JPX (JPEG 2000 Part 2) file format is especially useful for document, medical, and satellite imagery archiving systems . All LEADTOOLS Imaging Pro, Document Imaging, and Medical Imaging toolkits can read/parse JPX files. LEADTOOLS Document and Medical Imaging toolkits also add support for writing JPX files and manipulating JPX boxes, frames, GML Data, and other advanced JPX features. JPX support enables you to:

• Maintain full control of code streams, frames, and metadata

• Append and extract all standard metadata boxes, such as XML, digital signature, and intellectual property

• Append and extract additional images (frames)

• Save lists of bitmaps, such as 3D volumetric encoded slices

• Include support for 24, 32, 48, 64 bit RGB and 8, 12-16 bit grayscale* code streams

• Add opacity channels

• Read and write GML data

• Support fragmentation, making it possible to:

  • Edit an image, resaving the changed tiles and placing them at the end of the file

  • Distribute images across several disks for faster access

  • Distribute the image across the Internet, allowing only certain users access to the high quality or high resolution portions of the code stream

  • Reuse headers from within a code stream across multiple code streams (to minimize file overhead when storing similar code streams within the same JPX file)

The L_JP2_FILEINFO structure provides information about JPEG 2000 file contents. The L_JP2_XML_BOX structure provides information for an XML box. For a complete listing of functions that control, read, and manipulate box contents, see Raster Image Functions: Working with JPEG 2000. To determine the current settings for these features, use the L_JP2GetBoxes function. To change these features, use the L_JP2SetBoxes function.

LEADTOOLS JPX supports ANSI and UNICODE development in separate libraries. For information about the required .DLL file name and import library, please refer to Files To Be Included With Your Application.

Medical Toolkits

The Medical toolkits offer some additional, special functions. To determine the current settings for JPEG 2000 features, use the L_DicomGetJ2KOptions function. To change JPEG 2000 features, use the L_DicomSetJ2KOptions and functions. To get the default settings for JPEG2000 features, use the L_DicomGetDefaultJ2KOptions function.

For more information, refer to:

Compression Using LEAD and JPEG Formats

JPEG and LEAD Compressed Formats

Introduction: Bitmaps in Memory and in Files

Raster Image Functions: Working with JPEG 2000

Raster Image Functions: Working with JPX

Programming with JPEG 2000 Features

JPX File Comments

JPEG and LEAD File Comments

LEAD Image Optimizer Supported Formats