WSQ viewer

Opens WSQ (FBI's Wavelet Scalar Quantization) and other image file formats.

Supported image formats:

WSQ - FBI''s Wavelet Scalar Quantization

JP2 - JPEG-2000 Part-1

JPC - JPEG-2000 Code Stream

JPG - Joint Photographic Experts Group

PNG - Portable Network Graphics

BMP - Windows Bitmap Graphics

GIF - Compuserve Graphic Interchange Format

WEBP - Web Picture

HEIF - High Efficiency Image File

PBM - Portable Bitmap Format

PGM - Portable Graymap Format

PPM - Portable Pixmap Format

BIN - ANSI/NIST-ITL 1-2000 Type-8 signature (Uncompressed scanned binary image data)

BIN - ANSI/NIST-ITL 1-2000 Type-8 signature (ANSI/EIA-538-1988 facsimile compression)

WSQ format description

In the USA, fingerprints have traditionally been collected on cards, each card containing the inked impressions of all ten fingers. The U.S. Federal Bureau of Investigation's fingerprint database began in 1924 with a cataloged collection of 810,188 cards. By the start of World War II, this collection had grown to over 10 million cards, and by 1946 had reached over 100 million cards.

In 1995 this collection was contained on over 200 million cards stored in filing cabinets occupying one acre of floor space in the J. Edgar Hoover building in Washington D.C. and archive size was increasing at the rate of 30,000 to 50,000 new cards per day. Digitization of fingerprint cards seemed to be the most obvious choice and the project named FBI's Integrated Automated Fingerprint Identification System (IAFIS) was started to cope with the design and implementation of a national standard for collecting, encoding, storing, and retrieving digitized fingerprint images. According to the FBI standard fingerprints are stored as 8-bit grayscale images. Each fingerprint card, when digitized at 500 dpi requires about 10 Mbytes of storage. The FBI's entire collection would therefore consume two petabytes (2,000,000,000 megabytes) of electronic storage space.

The need for an effective compression technique was then very urgent. Unfortunately, neither the well-known lossless methods nor the JPEG methods were found to be satisfactory. Most lossy compression methods, such as JPEG, discard the smallest (highest frequency) details in images, and at higher compression ratios unacceptably distort the image. Contained within fingerprints are tiny details that are considered admissible points of identification in a court of law. To JPEG, these details may be regarded as noise and removed. The JPEG quantization matrix also allows blocking artifacts to occur in the image at compression ratios above about 10:1. Shifting bits to the high frequencies to preserve small details will only make the blocking worse. Lossless compression methods, such as LZW and JBIG, cannot achieve the high compression ratios of WSQ on fingerprint data, with 2:1 typically being the best. A new compression technique (with small acceptable loss), called Wavelet Scalar Quantization (WSQ) was developed and it became the FBI standard for the compression of 500 dpi fingerprint images.

WSQ is a lossy compression method that is well-suited for preserving the very high resolution details of grayscale images while maintaining high compression ratios of typically 12:1 to 15:1 on images that have not undergone "quality enhancements" (such as histogram equalization) to improve the appearance of the image.

WSQ file format specifications

Name: FBI's Wavelet Scalar Quantization file format.

Also known as: FBI Fingerprint Format or FBI WSQ

Application: The standard file format used by the FBI for storage and interchange of grayscale fingerprint images

Originator: FBI (U.S. Federal Bureau of Investigation)

Type: Bitmap

Colors: 8 bit grayscale

Compression: Wavelet Scalar Quantization

Maximum image size: 64K x 64K

Multiple images per file: No