ANSI INCITS-377-2009 pdf download Finger Pattern Data Interchange Format
4.14 Delta A Delta is that point on a ridge at or nearest to the point of divergence of two type lines, and located at or directly in front of the point of divergence .
4.15 Dimension The number of pixels in an acquired biometric sample image, either x- or y-direction.
4.16 Down-sample To reduce the resolution of an image by re-sampling the image. This reduces the number of pixels accordingly.
4.17 Encryption The act of converting plaintext into cyphertext through the use of an encryption algorithm.
4.18 Enrollment The process of collecting biometric samples from an individual and the subsequent preparation and storage of biometric reference templates.
4.19 Finger Pattern Subportion and/or down-sampled version of a raw fingerprint image (see 4.24).
4.20 Finger Pattern Interchange Data Data derived from the Finger Pattern and stored for subsequent matching with a candidate fingerprint.
4.21 Maximal Spatial Frequency The maximal spatial frequency is the (spatial) frequency at which exactly two samples of an image span a complete period of a (co)sinusoidal pattern. This is therefore the maximal spatial frequency that can be supported by a sampling resolution and is known as the Nyquist frequency.
4.22 Packed Data Format Data are stored in a compacted bit form with no record separators or field tags – fields are separated by byte count only.
4.23 Pad To embed an image in a larger array (usually filled with zeroes) to produce a resulting image of greater dimension.
4.24 Raw Fingerprint Image Biometric sample as captured by a fingerprint sensor. This raw image will usually retain the full resolution and spatial extent permitted by the sensor.