ISO IEC 39794-4:2019 pdf free

ISO IEC 39794-4:2019 pdf free.Information technology一Extensible biometric data interchange formats
This document is designed to accommodate both plain (flat) or rolled fingerprint images. Biometric systems perform better if the volar pad of the finger is centred both horizontally and vertically in the image capture area. Therefore, when capturing a fingerprint image, the centre of the fingerprint image should be located in the approximate centre of the image capture area.
For multiple finger verification and/or identification purposes, there exist fingerprint capture devices that will acquire images of multiple fingers during a single capture cycle. These devices are capable of capturing the plain impressions from two, three or four adjacent fingers of either hand during a single scanning. The plain impressions from the two thumbs or two index fingers can also be captured at one time. Therefore, with three placements of the fingers on a device’s scanning surface all ten fingers from an individual would be acquired in three scans – right four fingers, left four fingers, and two thumbs.
For these multi-finger captures, half of the captured fingers should be located to the left of the image centre and the other half of the fingers to the right of the image centre.
This document is also designed to accommodate images from the palm of the hand or from the side of the hand opposite the thumb also known as the “writer’s palm”. Most comparison subsystems perform better if the flat or fleshy part of the palm or writer’s palm is centred both horizontally and vertically in the image capture area. Therefore, when capturing a palmprint image, the centre of the palm or writer’s palm image area should be located in the approximate centre of the image capture area. The palm itself may be captured as one entity, or various pieces of it can be captured as single images such as the thenar (fleshy part behind the thumb), hypothenar (fleshy area opposite the thumb), or interdigital (area of the palm directly beneath the four fingers).ISO IEC 39794-4 pdf download.