Henry Classification System

The Henry Classification System is a long-standing method by which fingerprints are sorted by physiological characteristics for one-to-many searching. Developed by Sir Edward Henry in the late 1800s for criminal investigations in British India, it was the basis of modern day AFIS classification methods up until the1990s. In recent years, the Henry Classification System has generally been replaced by ridge flow classification approaches.

History and Development of the Henry Classification System

Although fingerprint characteristics were studied as far back as the mid-1600s, the use offingerprints as a means of identification did not occur until the mid-1800s. In roughly 1859, Sir William Herschel discovered that fingerprints remain stable over time and are unique acrossindividuals; as Chief Magistrate of the Hooghly district in Jungipoor, India, in 1877 he was the first to institute the use of fingerprints and handprints as a means of identification, signing legal documents, and authenticating transactions. The fingerprint records collected at this time were used for one-to-one verification only; as a means in which records would be logically filed and searched had not yet been invented.

In 1880, Dr. Henry Fauld wrote to Sir Charles Darwin, explaining a system for classifyingfingerprints, asking for his assistance in their development. Darwin was unable to assist Dr.Fauld, but agreed to forward the letter to his cousin, Sir Francis Galton. Dr. Henry Fauld and Sir Francis Galton did not engage in much correspondence, but in the following decade, theydevised very similar fingerprint classification systems. It is unclear whom to credit for theclassification system. However, we do know that Dr. Henry Fauld was the first European topublish the notion of scientific use of fingerprints in the identification of criminals. In 1892, Sir Francis Galton published his highly influential book, Finger Prints in which he described his classification system that include three main fingerprint patterns - loops, whorls and arches.

At the time, the alternative to fingerprints was Bertillonage, also known as Anthropometry.Developed by Alphonse Bertillon in 1879, Bertillonage consists of a meticulous method ofmeasuring body parts for the use of identifying criminals. In1892, the British Indian police force adopted Anthropometry. Two years later, Sir Edward Henry, Inspector General of the BengalPolice in India became interested in the use of fingerprints for the use of criminal identification.

Influenced by Sir Galton’s Finger Prints, the men corresponded regularly in 1894; and inJanuary 1896, Sir Henry ordered the Bengali Police to collect prisoners’ fingerprints inaddition to their anthropometric measurements. Expanding on Sir Galton’s classification system,Sir Henry developed the Henry Classification System between the years1896 to 1897. He was primarily assisted by Azizul Haque who developed a mathematical formula to supplement Henry's idea of sorting in 1024 pigeon holes based on fingerprint patterns, and Hem Chandra Bose, another Henry's assistant also helped refine the system, and both, on the recommendation of Henry received recognition years later by the British Government for their contribution. [ [http://www.jpgmonline.com/article.asp?issn=0022-3859;year=2000;volume=46;issue=4;spage=303;epage=8;aulast=Tewari] Tewari RK, Ravikumar KV. History and development of forensic science in India. J. Postgrad Med 2000,46:303-308.] [ [http://www.ias.ac.in/currsci/jan102005/185.pdf] J.S. Sodhi & Jasjeed Kaur. The forgotten Indian pioneers of fingerprint science, Current Science 2005, 88(1):185-191.] [ [http://www.amazon.com/dp/0786885289] Colin Beavan: Fingerprints: The Origins of Crime Detection and Murder Case that Launched Forensic Science, Hyperion, NY, USA, 2001.] TheHenry Classification System was to find worldwide acceptance in 1899.

In 1887 a commission was established to compare Anthropometry to the Henry ClassificationSystem. As the results were overwhelmingly in favor of fingerprints, fingerprinting wasintroduced to British India by the Governor General, and in 1900, replaced Anthropometry. Alsoin 1900, Sir Henry was sent to Natal, South Africa to assist in the reorganization of the localpolice force and establish a fingerprint bureau. His efforts in South Africa were highlysuccessful; and in 1901 Sir Henry returned to Britain and was appointed AssistantCommissioner of Scotland Yard, head of the Criminal Investigation Department. In the sameyear, the first UK fingerprint bureau was established at Scotland Yard. (Harling 1996) (Met)(Early)

Explanation of the Henry Classification System

The Henry Classification System allows for logical categorization of ten-print fingerprint records into primary groupings based on fingerprint pattern types. This system reduces the effort necessary to search large numbers of fingerprint records by classifying fingerprint records according to gross physiological characteristics. Subsequent searches (manual or automated) utilizing granular characteristics such as minutiae are greatly simplified. The Henry Classification System is a method to classify fingerprints and exclude potential candidates. This system should NEVER be used for individualization.

The Henry Classification System assigns each finger a number according to the order in whichis it located in the hand, beginning with the right thumb as number 1 and ending with the leftpinky as number 10. The system also assigns a numerical value to fingers that contain a whorlpattern; fingers 1 and 2 each have a value of 16, fingers 3 and 4 have a value of 8, and so on,with the final two fingers having a value of 1. Fingers with a non-whorl pattern, such as an arch or loop pattern, have a value of zero. (Harling 1996). The value of 1 is added to each sum of the whorls with the maxiumobtainable being 32. Thus, the primary classification is a fraction between1/1 to 32/32 where 1/1 would indicate no whorl patterns and 32/32 would mean that all fingers had whorl patterns. (Roberts 2008)

Impact on Current Biometric Systems

The Henry Classification System has been a highly influential force in the formation of current AFIS technology (Automated Fingerprint Identification System). When AFIS technology was first introduced, it was primarily envisioned used as a tool to expedite the manual searching of fingerprint records, eventually reducing matching time requirements from months to hours. At that time, most forensic hardcopy fingerprint files were sorted according to the Henry Classification System and the first AFIS solutions attempted to emulate the Henry process.

Up until the mid 1990s, it was not unusual for a state or city to continue to maintain its physical file of Henry-sorted fingerprint cards just in case a disaster occurred in the AFIS. As processing speeds, network throughput capacities, and system reliability increased, it was no longer necessary for automated fingerprint matching to mirror what had been the manual processes.AFIS began to classify fingerprints according to the distance between the core and delta, minutiae locations, and pattern type; the later being based on the Henry Classification System. Presently, there are some forensic AFIS solutions (e.g. state and local) that still employ a Henry Classification System based manual fingerprint filing. However, other than for legacy systems, the Henry Classification System is not essential for automated systems. (Carlton)

References

External links

* [http://www.sethoscope.net/henryfp/ Javascript implementation of Henry Classification]

Other Resources

* [http://ridgesandfurrows.homestead.com http://ridgesandfurrows.homestead.com]

* [http://www.correctionhistory.org/html/chronicl/dcjs/html/nyidbur2.html http://www.correctionhistory.org/html/chronicl/dcjs/html/nyidbur2.html]