Wavelet scalar quantization

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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.

Contents

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

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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.

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WSQ can refer to:

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LuraTech

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References

  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