Henry Classification System
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The Henry Classification System is a long-standing method by which fingerprints are sorted by physiological characteristics for one-to-many searching. Developed by Hem Chandra Bose and Azizul Haque and Sir Edward Henry in the late 19th century for criminal investigations in British India, it was the basis of modern day AFIS (Automated Fingerprint Identification System) classification methods up until the 1990s. In recent years, the Henry Classification System has generally been replaced by ridge flow classification approaches.
History and development
Henry Classification System was to find worldwide acceptance in 1899. In 1897 a commission was established to compare Anthropometry to the Henry Classification System. As the results were overwhelmingly in favor of fingerprints, fingerprinting was introduced to British India by the Governor General, and in 1900, replaced Anthropometry. Also in 1900, Henry was sent to Natal, South Africa to assist in the reorganization of the local police force and establish a fingerprint bureau. His efforts in South Africa were highly successful; and in 1901 Sir Henry returned to Britain and was appointed Assistant Commissioner of Scotland Yard, head of the Criminal Investigation Department. In the same year, the first UK fingerprint bureau was established at Scotland Yard. (Harling 1996) (Met) (Early)
Explanation
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 which is it located in the hand, beginning with the right thumb as number 1 and ending with the left pinky as number 10. The system also assigns a numerical value to fingers that contain a whorl pattern; fingers 1 and 2 each have a value of 16, fingers 3 and 4 have a value of 8, fingers 5 and 6 have a value of 4, fingers 7 and 8 have a value of 2, and 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.[1] The sum of the even finger value is then calculated and placed in the numerator of a fraction. The sum of the odd finger values is placed in the denominator. The value of 1 is added to each sum of the whorls with the maximum obtainable on either side of the fraction being 32. Thus, the primary classification is a fraction between 1/1 to 32/32, where 1/1 would indicate no whorl patterns and 32/32 would mean that all fingers had whorl patterns.[2]
Example of a Henry Classification:
| Key | Major | Primary | Secondary | Sub-Secondary | Final |
|---|---|---|---|---|---|
| 16 | M | 9 | R | IIO | 15 |
| M | 2 | U | OOI |
Key- Ridge count first loop
Major- Value of the ridge counts or the tracings of fingers #1, #6
Primary- Summation of the value of: Whorl type patterns fingers (#2, #4, #6, #8, #10 for Numerator), (#1, #3, #5, #7, #9 for Denominator); Value of fingers as whorls: #1 & #2 (16), #3 & #4 (8), #5 & #6 (4), #7 & #8 (2), #9 & #10 (1); Plus 1 in both Numerator and Denominator.
Secondary- Pattern types in fingers #2 and #7, (U) Ulna Loop, (R) Radial Loop, (W) Whorl, and (A) Arch
Sub-Secondary- Value of ridge counts or tracing- fingers #2, #3, #4 in Numerator; #7, #8, #9 in Denominator.
Final- Ridge count Loop in finger #5. If #5 is not a Loop, use #10. If no Loop in #5 and #10, there is no final.[3]