bmfinance.comHand Scan Recognition Time Clocks
The time and attendance industry has been using hand scan technology for nearly 20 years . To use a hand scan bundy clock or access control terminal the user enters their ID and puts their right hand on the platen (a flat reflective surface with guide posts which lie in between the users fingers) and the hand scan unit will quickly perform a match against a registered template and log them in or give then access to a secure area. .
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This technology uses a camera and a series of mirrors to build a three dimensional picture of the users hand. The processor in the hand scan measures the users hand geometry including the length and thickness of each finger which it converts into an algorithm. This mathematical representation of the hand is stored in a template and is referenced when matching the user during subsequent logging events.
The algorithm is adjusted periodically and because of this feature it compensates for changes in the size of the users hand so, if the user gains or loses weight the device compensates. Interestingly the unit does depend on the user having a right hand with no fingers missing . Having said that, testing I completed recently has shown that a left hand turned upside down will work correctly.
Hand scan terminals are an established technology but they are not widely used in either time and attendance or access control applications. One of the advantages of hand scan technology is that user’s hands can be scratched, sut or even dirty. However the platen and mirrors will need to be cleaned frequently . This makes the hand scan a very effective biometric device.
Based on the fact that hand scan terminals are actually more reliable than most of the other alternatives it is surprising that they have not been more broadly implemented . One possible reason is that they are more expensive than most fingerprint readers and they have no embedded software so they cannot be used as a stand alone time clock. Additionally, the manufacturers have not assigned exclusivity to a time and attendance solution provider nor have they developed their own award interpretation software .
Hand scan time clocks tend to be used in harsh environments when fingerprint units simply can’t recognise users who frequently damage their fingers. Hand scan is most commonly found in manufacturing, mining and construction. In those environments they tend to be installed in a dust proof enclosure to prevent the mirrors and camera becoming impacted by dirt. Unfortunately those environments are also prone to accidental or deliberate mechanical shock which is likely to misalign the camera and cause issues with template recognition.
Because hand scan terminals do not have any useful embedded software for time and attendance it is important to find a supplier with award interpretation or attendance software properly integrated with the hand punch terminals. Your selected software provider should be able to demonstrate that they are an established hand scan solution provider as integration is never as straightforward as you might think and while it may appear to work in the short time there may be some hidden integration issues down the track. You don’ want to be a hardware integration crash test dummy .
In summary , hand scan technology when coupled with some decent third party software is a great alternative for harsh environments because it is quite faultless in its recognition capabilities. You will however , almost certainly need a good third party time and attendance provider with an established track record in hand scan integration.
Keep in mind that the hand scan terminals are not as robust as some of the the other biometric clocks on offer and will suffer physical abuse .
James Bell
Time and Attendance Consultant