a a a


Vol.32 No.2 May 1998

PIKS and BIIF Explored

George S.Carson
GSC Associates, Inc.

May 98 Columns
SIGGRAPH Public Policy Comics from the Other Side

George S.Carson
Previous article by George S.Carson Next article by George S.Carson

This issue’s column is an introduction to the Image Processing and Interchange standards (ISO/IEC 12087) developed by ISO/IEC JTC 1/ SC 24 (Computer Graphics and Image Processing.). First, Bill Pratt of PixelSoft, the Editor of the Programmer's Imaging Kernel System (PIKS) International Standard (ISO/IEC 12087-1:1995), describes PIKS and how it can be applied. Next, I describe the Basic Image Interchange Format (BIIF), ISO/IEC 12087-1:1998, and its applications.

Overview of the Programmer's Imaging Kernel System (PIKS) Application Program Interface

William K. Pratt
PixelSoft, Inc.


The Programmer's Imaging Kernel System (PIKS), is a C language Application Program Interface (API) for image processing. It is part of the International Standard for Image Processing and Interchange (ISO/IEC 12087) developed by the Subcommittee for Computer Graphics and Image Processing (ISO/IEC JTC 1 SC 24) of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC).

PIKS contains a rich set of operators that perform manipulations of images or of data objects extracted from images in order to enhance, restore or assist in the extraction of information from images. These operators range from primitive operators, such as convolution and histogram generation to complex, higher level operators such as histogram equalization and edge detection.

The following sections provide a brief overview of PIKS. References 1 to 4 provide further information.

PIKS Imaging Model

Figure 1 describes the PIKS imaging model. The solid lines indicate data flow and the dashed lines indicate control flow. The PIKS application program interface consists of four major parts:

  • Data objects
  • Operators, tools and utilities
  • System mechanisms
  • Import and export

The PIKS data objects include both image and image-related, non-image data objects. The operators, tools and utilities are functional elements that are used to process images or data objects extracted from images. The system mechanisms manage and control the processing. PIKS receives information from the application to invoke its system mechanisms, operators, tools and utilities, and returns certain status and error information to the application. The import and export facility provides the means of accepting images and image-related data objects from an application, and for returning processed images and image-related data objects to the application. PIKS can transmit its internal data objects to an external facility through the ISO-standard Image Interchange Facility (IIF) (ISO/IEC 12087-3) or the Basic Image Interchange Format (BIIF). Also, PIKS can receive data objects in its internal format, which have been supplied by the IIF or the BIIF.

PIKS Data Objects

A PIKS image object is a five-dimensional (5D) collection of pixels whose structure is:

  • x: horizontal space index
  • y: vertical space index
  • z: depth space index
  • t: temporal index
  • b: color or spectral band index

PIKS supports the following pixel data types:

  • Boolean
  • Non-negative integer
  • Signed integer
  • Real arithmetic
  • Complex arithmetic

PIKS also supports several image related, non-image data objects. These include:

  • Feature list: A collection of pairs of elements in which the first element is a pixel coordinate and the second element is an image measurement, e.g. gradient amplitude above a threshold value.
  • Histogram: A construction of the counts of pixels with some particular amplitude value.
  • Lookup table: A structure that contains pairs of entries in which the first entry is an input value to be matched and the second is an output value.
  • Matrix: A two-dimensional array of elements that is used in vector algebra operations.
  • Neighborhood array: A multidimensional moving window associated with each pixel of an image, e.g. convolution impulse response function array.
  • Region-of-interest: A general mechanism for pixel-by-pixel selection.

PIKS Operators

The following is a list of PIKS operators categorized by functionality with examples of each class. The numbers in parentheses are the number of operators in each class.

  • Analysis (9): extrema, Hough transform, moments
  • Classification (2): Bayes classifier, nearest neighbor classifier
  • Colour (5): linear color conversion, subtractive color conversion
  • Complex Image (4): complex conjugate, complex magnitude
  • Correlation (2): cross-correlation, template match
  • Edge detection (3): orthogonal gradient, second derivative
  • Enhancement (7): histogram modification, outlier removal, unsharp mask
  • Ensemble (8): alpha blend, dyadic arithmetic, Z merge
  • Feature Extraction (3): label objects, Laws texture, window statistics
  • Filtering (4): two-dimensional convolve, homomorphic filtering, median filtering
  • Geometric (12): resize, rotate, sub-sample, control point warp, zoom
  • Histogram Shape (2): one-dimensional and two-dimensional histogram shape
  • Morphological (8): erosion, dilation, fill region, open, close
  • Pixel Modification (2): draw pixels, paint pixels
  • Point (18): complement, level slice, threshold, window-level
  • Presentation (2): dither, diffuse
  • Shape (4): perimeter code generator, shape metrics, spatial moments
  • Unitary transform (4): cosine transform, Fourier transform, Hadamard transform
  • 3D specific (4): sequence average, sequence running measures, 3D slice

PIKS Conformance Profiles

Because image processing requirements vary considerably across various applications, PIKS functionality has been subdivided into the following four nested sets of functionality called conformance profiles. They are:

  • PIKS Foundation: Basic image processing functionality for monochrome and color images whose pixels are represented as Boolean values or as non-negative or signed integers. It contains 96 PIKS elements.
  • PIKS Technical: Intermediate image processing functionality for monochrome, color, volume, temporal and spectral images whose pixels are represented as Boolean values, non-negative or signed integers, real arithmetic values and complex arithmetic values. PIKS Technical is a superset of PIKS Foundation functionality. It contains 174 PIKS elements.
  • PIKS Scientific: Complete set of image processing functionality for all image structures and pixel data types. PIKS Scientific is a superset of PIKS Technical functionality. It contains 248 PIKS elements.
  • PIKS Full: Complete set of image processing functionality for all image structures and pixel data types plus the capability to chain together PIKS processing elements and to operate asynchronously. PIKS Full is a superset of PIKS Scientific functionality. It contains 266 PIKS elements.
William K.Pratt is a pioneer in digital image processing. He is responsible for the discovery of the transform image coding concept, which is the basis for the JPEG and MPEG image coding standards. He is the inventor of a facsimile coding system and a means of high-speed image convolution, as well as the document editor of the Programmer’s Imaging Kernel System (PIKS) application program interface standard. Pratt is the author of Laser Communications, Digital Image Processing, PIKS Foundation C Programmer’s Guide and XIL: An Imaging Foundation Library.

William K.Pratt
PixelSoft, Inc.
101 First Street, Suite 429
Los Altos, CA 94022

The copyright of articles and images printed remains with the author unless otherwise indicated.

PIKS Status

The PIKS Functional Specification was published in 1994, and in the following year the C language binding was published. The first commercial implementation of the PIKS Foundation profile was released by PixelSoft in early 1995. The National Institute of Standards and Technology (NIST) has undertaken the development of a conformance test suite for private and commercial implementations. The United States National Imagery and Mapping Agency (NIMA) (formerly Central Imagery Office) has endorsed PIKS for imagery applications.


  1. Information Technology, Computer Graphics and Image Processing, Image Processing and Interchange, Functional Specification, Part 1: Common Architecture for Imaging, ISO/IEC 12087-1:1995.
  2. Information Technology, Computer Graphics and Image Processing, Image Processing and Interchange, Functional Specification, Part 2: Programmer's Imaging Kernel System Application Program Interface, ISO/IEC 12087-2:1994.
  3. Information Technology, Computer Graphics and Image Processing, Image Processing and Interchange, Application Program Interface Language Bindings, Part 4: C, ISO/IEC 12088-4:1995.
  4. Pratt, W. K. PIKS Foundation C Programmer's Guide, Manning Publications, Prentice-Hall, 1995.

Overview of the Basic Image Interchange Format (BIIF)

George S.Carson
GSC Associates

The Subcommittee for Computer Graphics and Image Processing (ISO/IEC JTC 1 SC 24) has recently completed a new addition to the International Standard for Image Processing and Interchange (ISO/IEC 12087). International Standard 12087-5, Basic Image Interchange Format (BIIF), provides a proven foundation for interoperability in the interchange of imagery and imagery-related data among computer imaging applications. Development work on this standard started in October 1995 in Vienna, Austria with the preparation of the first Working Draft (WD). The standard was finalized in February 1998 in Annapolis, MD, U.S.A., with the resolution of the comments on the Draft International Standard (DIS) ballot and agreement on the final text of the International Standard.

The basis from which BIIF was developed was a U.S. government specification called the National Imagery Transmission Format Standards (NITFS) [2]. NITFS was proven by application to the activities of several departments within the U.S. government in support of military, intelligence, drug interdiction, law enforcement, treaty enforcement, geospatial positioning and other applications. (Note: There is a suite of military standards that make up the “NITF Standard.” They address specific guidance for the application of JPEG compression, bi-level compression, vector quantization and CGM. More information can be found at the web site).


  • Provides a means whereby diverse applications can share digital imagery and associated information about the imagery.
  • Allows an application to exchange comprehensive information to users with diverse needs or capabilities, allowing each user to select only those data items that correspond to their needs and capabilities to interpret and use the data.
  • Minimizes formatting overhead, particularly for those applications exchanging only a small amount of data and for applications needing to exchange imagery over bandwidth constrained communications channels.
  • Provides a mechanism to interchange PIKS (ISO/IEC 12087-2) image and image-related objects.
  • Provides extensibility to accommodate future imagery-related data types, including objects.

Figure 2 illustrates the structure of a BIIF file that includes images, symbols, labels, text and extensions.

Image Compression

The BIIF supports the application of standard digital imagery compression techniques, both lossless and lossy. For example, it supports the use of the Joint Photographic Experts Group (JPEG) compression algorithms specified by ISO/IEC 10918, Digital compression and coding of continuous-tone still images. It also allows for the use ITU-T T.4 Standardization of Group 3 Facsimile Apparatus to support compression of bi-tonal imagery. Additionally, BIIF anticipates the use and application of future digital imagery compression methodologies forthcoming from such activities as JPEG 2000.

Non-destructive Overlays

The BIIF allows for imagery presentation consisting of images with overlays of image, symbolic and textual annotations in a manner wherein the underlying data is not lost. Overlays are such that the data content of each image, symbol and textual component in the composite presentation is preserved rather than lost through the “burned-in” approach used in some other digital imagery formats. Figure 3 illustrates how BIIF uses common coordinates to combine different types of information in a system of “non-destructive” overlays.

Symbolic and Textual Annotation

Graphical symbol and textual annotation of the imagery is supported through the use of ISO/IEC 8632, Computer Graphics Metafile (CGM) for the storage and transfer of picture description information.

Textual Adjuncts

The BIIF provides the means to include textual information about the image product contained in the BIIF file. The BIIF supports multi-lingual text content in accordance with ISO/IEC 10646 Universal Multiple-Octet Coded Character Set (USC) and its associated transforms (e.g. ISO/IEC 10646 Amendment 2, UCS Transformation 8).

Image Related Extension Data

The BIIF supports the optional inclusion of image related extension data. The inclusion of extension data provides the ability to add data/information about the imagery (metadata) that is not contained in the minimum basic format structure of the BIIF. The use of extension data is often domain specific to the community of interest using a specific profile of BIIF. Exemplary uses of extension data include:

  • Data about people, buildings, places, landmarks, equipment or other objects that may appear in the image.
  • Data to allow correlation of information among multiple images and annotations within a BIIF file.
  • Data about the source of the imagery, the sensor used to digitize the image, the equipment settings used to obtain the digital image, x-ray, etc.
  • Data to allow geopositioning of items in the imagery or measurement of distances of items in the imagery.
  • Data to support the cataloging of imagery for archival and subsequent discovery and retrieval.

Current Products and Applications

The BIIF is based on an approach that has been used over that past several years in a fielded operational environment. It is supported by at least a dozen commercial providers of imagery application software products that are readily available “off-the-shelf.” The list includes:

  • NORTHROP VIEW(TM) from Northrop Grumman
  • ELT Models 1000/2000/2500/3000/7000 from Paragon Imaging, Inc.
  • Global Image Viewer from Paragon Imaging, Inc.
  • ELT/NET from Paragon Imaging, Inc.
  • VITec Electronic Light Table (ELT) from VITec
  • Digital Imagery and Exploitation System (DIEPS) from GTE
  • IMAGINE from ERDAS, Inc.
  • NITF for Digital Camera System (DCS) from Eastman Kodak
  • Imaging and Communications Environment (ICE) from PhotoTelesis, Inc.
  • Portable Receive Transmit System 1N (PORTS 1N) from Harris
George S.(Steve) Carson is President of GSC Associates of Las Cruces, NM, a systems engineering consulting firm specializing in real-time signal and information processing systems. He is the Chairman of ISO/IEC JTC I/SC 24 (Computer Graphics and Image Processing) and has been involved in ANSI and ISO standards development for 20 years.

George S.Carson
GSC Associates, Inc.
5272 Redman Road
Las Cruces, NM 88011

Tel: +1-505-521-7399

The copyright of articles and images printed remains with the author unless otherwise indicated.

The format is now being adopted for the exchange of digital imagery products among nations of the North Atlantic Treaty Organization (NATO). It is the specified digital imagery interchange format for use among nations subscribing to “Standardization of Formats for the Exchange of Digital Data among States Party to the Open Skies Treaty” (27 nation members). The United States Federal Geographic Data Committee (FGDC) is in the process of including BIIF as a means for exchanging raster data in its Spatial Data Transfer Standard (SDTS). The FGDC is comprised of representation from the Departments of Agriculture, Commerce, Defense, Energy, Housing and Urban Development, Interior, State and Transportation; the Environmental Protection Agency; the Federal Emergency Management Agency; the Library of Congress; the National Aeronautics and Space Administration; the National Archives and Records Administration; and the Tennessee Valley Authority.

Conformance Test Criteria and Test Services

Conformance test criteria and conformance test services have been established for the use of BIIF within the US Department of Defense. Over 40 defense system applications have been tested to date for conformance with the military use of BIIF. The Department of Defense has made these same test services available to commercial concerns for use on a cost-reimbursable basis.


  1. Information Technology, Computer Graphics and Image Processing, Image Processing and Interchange, Functional Specification, Part 5 Basic Image Interchange Format (BIIF), ISO/IEC 12087-5:1998.
  2. MIL-STD-2500B, National Imagery Transmission Format (Version 2.1) for the National Imagery Transmission Format Standard.