Wavelet scalar quantization

Last updated

The Wavelet Scalar Quantization algorithm (WSQ) is a compression algorithm used for gray-scale fingerprint images. It is based on wavelet theory and has become a standard for the exchange and storage of fingerprint images. WSQ was developed by the FBI, the Los Alamos National Laboratory, and the National Institute of Standards and Technology (NIST).

Fingerprint biometric identifier

A fingerprint in its narrow sense is an impression left by the friction ridges of a human finger. The recovery of fingerprints from a crime scene is an important method of forensic science. Fingerprints are easily deposited on suitable surfaces by the natural secretions of sweat from the eccrine glands that are present in epidermal ridges. These are sometimes referred to as "Chanced Impressions".

Wavelet function for integral Fourier-like transform

A wavelet is a wave-like oscillation with an amplitude that begins at zero, increases, and then decreases back to zero. It can typically be visualized as a "brief oscillation" like one recorded by a seismograph or heart monitor. Generally, wavelets are intentionally crafted to have specific properties that make them useful for signal processing. Using a "reverse, shift, multiply and integrate" technique called convolution, wavelets can be combined with known portions of a damaged signal to extract information from the unknown portions.

Los Alamos National Laboratory research laboratory for the design of nuclear weapons

Los Alamos National Laboratory is a United States Department of Energy national laboratory initially organized during World War II for the design of nuclear weapons as part of the Manhattan Project. It is located a short distance northwest of Santa Fe, New Mexico in the southwestern United States.


This compression method is preferred over standard compression algorithms like JPEG because at the same compression ratios WSQ doesn't present the "blocking artifacts" and loss of fine-scale features that are not acceptable for identification in financial environments and criminal justice. [1]

JPEG Lossy compression method for reducing the size of digital images

JPEG is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography. The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality.

Most American law enforcement agencies use WSQ for efficient storage of compressed fingerprint images at 500 pixels per inch (ppi). For fingerprints recorded at 1000 ppi, law enforcement (including the FBI) uses JPEG 2000 instead of WSQ. [2]

Pixel density number of dots per area of an image

Pixels per inch (ppi) or pixels per centimeter (ppcm) are measurements of the pixel density (resolution) of an electronic image device, such as a computer monitor or television display, or image digitizing device such as a camera or image scanner. Horizontal and vertical density are usually the same, as most devices have square pixels, but differ on devices that have non-square pixels.

JPEG 2000 image compression standard and coding system

JPEG 2000 (JP2) is an image compression standard and coding system. It was created by the Joint Photographic Experts Group committee in 2000 with the intention of superseding their original discrete cosine transform-based JPEG standard with a newly designed, wavelet-based method. The standardized filename extension is .jp2 for ISO/IEC 15444-1 conforming files and .jpx for the extended part-2 specifications, published as ISO/IEC 15444-2. The registered MIME types are defined in RFC 3745. For ISO/IEC 15444-1 it is image/jp2.

See also

Related Research Articles

In signal processing, data compression, source coding, or bit-rate reduction involves encoding information using fewer bits than the original representation. Compression can be either lossy or lossless. Lossless compression reduces bits by identifying and eliminating statistical redundancy. No information is lost in lossless compression. Lossy compression reduces bits by removing unnecessary or less important information.

Image compression Reduction of image size to save storage and transmission costs

Image compression is a type of data compression applied to digital images, to reduce their cost for storage or transmission. Algorithms may take advantage of visual perception and the statistical properties of image data to provide superior results compared with generic data compression methods which are used for other digital data.

Fractal compression is a lossy compression method for digital images, based on fractals. The method is best suited for textures and natural images, relying on the fact that parts of an image often resemble other parts of the same image. Fractal algorithms convert these parts into mathematical data called "fractal codes" which are used to recreate the encoded image.

ICER is a wavelet-based image compression file format used by the NASA Mars Rovers. ICER has both lossy and lossless compression modes.

Automated fingerprint identification is the process of using a computer to match fingerprints against a database of known and unknown prints. Automated fingerprint identification systems (AFIS) are primarily used by law enforcement agencies for criminal identification purposes, the most important of which is the identification of a person suspected of committing a crime or linking a suspect to other unsolved crimes.

Mladen Victor Wickerhauser was born in Zagreb, SR Croatia, in 1959. He is a graduate of the California Institute of Technology, and Yale University.

Cohen–Daubechies–Feauveau wavelet

Cohen–Daubechies–Feauveau wavelet are the historically first family of biorthogonal wavelets, which was made popular by Ingrid Daubechies. These are not the same as the orthogonal Daubechies wavelets, and also not very similar in shape and properties. However, their construction idea is the same.

Image file formats are standardized means of organizing and storing digital images. Image files are composed of digital data in one of these formats that can be rasterized for use on a computer display or printer. An image file format may store data in uncompressed, compressed, or vector formats. Once rasterized, an image becomes a grid of pixels, each of which has a number of bits to designate its color equal to the color depth of the device displaying it.

MrSID is an acronym that stands for multiresolution seamless image database. It is a file format developed and patented by LizardTech for encoding of georeferenced raster graphics, such as orthophotos.

ECW is a proprietary wavelet compression image format optimized for aerial and satellite imagery. It was developed by Earth Resource Mapping, and is now owned by Intergraph part of Hexagon AB. The lossy compression format efficiently compresses very large images with fine alternating contrast while retaining their visual quality.

Wavelet transform mathematical technique used in data compression and analysis

In mathematics, a wavelet series is a representation of a square-integrable function by a certain orthonormal series generated by a wavelet. This article provides a formal, mathematical definition of an orthonormal wavelet and of the integral wavelet transform.

Lossless JPEG is a 1993 addition to JPEG standard by the Joint Photographic Experts Group to enable lossless compression. However, the term may also be used to refer to all lossless compression schemes developed by the group, including JPEG 2000 and JPEG-LS.

WSQ can refer to:

Progressive Graphics File file format

PGF is a wavelet-based bitmapped image format that employs lossless and lossy data compression. PGF was created to improve upon and replace the JPEG format. It was developed at the same time as JPEG 2000 but with a focus on speed over compression ratio.

Ocarina Networks

Ocarina Networks was a technology company selling a hardware/software solution designed to reduce data footprints with file-aware storage optimization. A subsidiary of Dell, their flagship product, the Ocarina Appliance/Reader, released in April 2008, uses patented data compression techniques incorporating such methods as record linkage and context-based lossless data compression. The product includes the hardware-appliance-based compressor, the Ocarina Optimizer, and a real-time decompressor, the software-based Ocarina Reader.


LuraTech is a software company with offices in Remscheid, Berlin, London, and in the United States, which makes products for handling and conversion of digital documents. Its customers are primarily organizations involved in long-term document archiving and scan service providers. It is a member of the PDF Association.

CineForm Intermediate is an open source video codec developed for CineForm Inc by David Taylor, David Newman and Brian Schunck. On March 30, 2011, the company was acquired by GoPro which in particular wanted to use the 3D film capabilities of the CineForm 444 Codec for its 3D HERO System.

The Integrated Automated Fingerprint Identification System (IAFIS), is a computerized system maintained by the Federal Bureau of Investigation (FBI) since 1999. It is a national automated fingerprint identification and criminal history system. IAFIS provides automated fingerprint search capabilities, latent searching capability, electronic image storage, and electronic exchange of fingerprints and responses. IAFIS houses the fingerprints and criminal histories of 70 million subjects in the criminal master file, 31 million civil prints and fingerprints from 73,000 known and suspected terrorists processed by the U.S. or by international law enforcement agencies.

JPEG XT is an image compression standard which specifies backward-compatible extensions of the base JPEG standard.


  1. Jain, Anil; Pankanti, Sharath (2001). "Automated Fingerprint Identification and Imaging Systems". Advances in Fingerprint Technology (2nd ed.). CRC Press. pp. 275–326. ISBN   978-0-8493-0923-6.
  2. Fingerprint