Optical Figer Print Scanner - Online Article

OPTICAL   FINGER PRINT SCANNER

We all may know about the finger print scanner which is a popular device to identify the person  only with their thumb print. It is of two types :optical scanner and capacitor scanner. But this article is only related to optical figure print scanner. Before  that we must familiar with the terms I have explained below:

IMPORTANT TERMS:

CCD: charge coupled device is a electronic device which is used to convert electrical signals in to analog signals.the basi principle involved in this is the movement of electrical charges.It has two important blocks. they are PHOTOACTIVE REGION which captures the image at 1D form and TRANSMISSION REGION which is used for moving the charges to shift register.

RIDGES AND VALLEYS:

They both are found at the tip of the thumb.It differs from one person to another.this  is used to identify the person.

WORKING:

The electrical signal created in response to the light hitting on the CCD forms pixels which are collectively joined to form an image. The scanning device consists of a glass plate, on top of which you are supposed to place your finger. After the scanning takes place, an inverted image of the finger is stored. This image will show the ridges and valleys of your finger.The ridges is the darker part of your thumb image and valley is the lighter part of your thumb image.It is also havig the capacity to check tke image once again and indicates if it finds.

This scanned image is then compared with an earlier existing finger print of yours to get the correct identity. The comparison is carried out by the processor and the comparison is made between the valleys and ridges. Though the steps are simple, very complex algorithms must be carried out to perform this operation. Though your whole fingerprint is recorded, the computer takes only parts of the print to compare with other records.

ADVANTAGES:

  • No one may hack your finger unlike password.
  • No one can use your finger as that your lost id cards.

DISADVANTAGES:

  • It reads the images also instead of original finger.

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