Working Draft -- 2 December 2005 

Recommendations for Revision of ANSI/NIST ITL 1-2000 

Type-17 Iris Data Logical Record 

Working Draft 
Recommendations for ANSI/NIST ITL 1-2000 Iris Data Logical Record

Iris Data Record - Suggested Text 

A. Type-17 Iris data record 

The Type-17 tagged-field logical record shall contain and be used to exchange iris image data. 

Generic iris images may exchanged using the mandatory fields of this record type which are 

entirely consistent with the mandatory fields of a Type-16 record. Additionally, the optional 

fields may be used to exchange the additional data available in the INCITS 379-2004 – Iris 

Image Interchange Format standard. 

The INCITS 379-2004 standard specifies two alternative image interchange formats for 

biometric authentication systems that utilize iris recognition. The first is based on a rectilinear 

image storage format that may be a raw, uncompressed array of intensity values or a 

compressed format such as that specified by the JPEG standard. Images may be 

monochrome or color with 256 or more intensity levels (grey or per-color), and vary in size 

depending on field of view and compression. 

The second format is based on a polar image specification that requires certain pre-processing 

and image segmentation steps, but produces a much more compact data structure that 

contains only iris information. The polar image may be either raw or compressed format. 

A.1 Fields for the Type-17 logical record 

The following paragraphs describe the data contained in each of the fields for the Type-17 

logical record. Within a Type-17 logical record, entries shall be provided in numbered fields. It 

is required that the first two fields of the record are ordered, and the field containing the iris 

binary data shall be the last physical field in the record. For each field of the Type-17 record, 

Table 1 lists the “condition code” as being mandatory “M” or optional “O”, the field number, the 

field name, character type, field size, and occurrence limits. Based on a three-digit field 

number, the maximum byte count size for the field is given in the last column. As more digits 

are used for the field number, the maximum byte count will also increase. The two entries in 

the “field size per occurrence” include all character separators used in the field. The 

“maximum byte count” includes the field number, the information, and all the character 

separators including the “GS” character. 

Working Draft 
Recommendations for ANSI/NIST ITL 1-2000 Iris Data Logical Record

Table 1. Type-17 Iris Data Record Layout 

Ident Cond 

Code 

Field 

Number 

Field Name Char 

Type 

Field size per 

occurrence 

Occur 

count 

Max byte 

count 

min max min max 

LEN M 17.001 LOGICAL RECORD LENGTH N 4 8 1 1 15 

IDC M 17.002 IMAGE DESIGNATION 

CHARACTER 

N 2 5 1 1 12 

M 17.003 FEATURE IDENTIFIER N 2 2 1 1 9 

M 17.004 MAKE/MODEL/SERIAL 

NUMBER 

ANS 4 151 1 1 158 

M 17.005 IMAGE FORMAT N 2 3 1 1 10 

HLL M 17.006 HORIZONTAL LINE LENGTH N 4 5 1 1 12 

VLL M 17.007 VERTICAL LINE LENGTH N 4 5 1 1 12 

SLC M 17.008 SCALE UNITS N 2 2 1 1 9 

HPS M 17.009 HORIZONTAL PIXEL SCALE N 2 5 1 1 12 

VPS M 17.010 VERTICAL PIXEL SCALE N 2 5 1 1 12 

CGA M 17.011 COMPRESSION ALGORITHM AN 5 7 1 1 14 

BPX M 17.012 BITS PER PIXEL N 2 3 1 1 10 

O 17.013 IRIS IMAGE QUALITY N 3 4 0 1 11 

O 17.014 ROTATION ANGLE OF EYE AN 2 5 0 1 12 

O 17.015 ROTATION UNCERTAINTY AN 2 5 0 1 15 

O 17.016 IMAGE PROPERTIES N 7 7 0 1 14 

O 17.017 DEVICE UNIQUE IDENTIFIER ANS 17 17 0 1 24 

O 17.018 GLOBAL UNIQUE IDENTIFIER AN 7 7 0 1 14 

O 17.019 IMAGE TRANSFORMATION N 2 2 0 1 9 

RSV O 17.020 - 

17.199 

RESERVED FOR FUTURE 

INCLUSION 

-- -- -- -- -- -- 

UDF O 17.200 - 

17.998 

USER-DEFINED FIELDS -- -- -- -- -- -- 

M 17.999 IRIS IMAGE B 2 -- 1 1 -- 

A.1.1 Field 17.001: Logical Record Length (LEN) 

This mandatory field shall contain the total count of the number of bytes in the Type-17 logical 

record. This field shall specify the length of the record including every character of every field 

contained in the record and the information separators. 

A.1.2 Field 17.002: Image Designation Character (IDC) 

This mandatory field shall be used to identify the image data contained in the record. This IDC 

shall match the IDC found in the file content (CNT) field of the Type-1 record. 

A.1.3 Field 17.003: Feature Identifier (###) 

This mandatory field shall contain an identifier for which eye is represented by the image in the 

record. An entry of “0” in this field indicates that the image in this record is undefined. An 

entry of “1” in this field indicates that the image in this record is of a right eye. An entry of “2” in 

this field indicates that the image in this record is of a left eye. 

A.1.4 Field 17.004: Make/Model/Serial Number (###) 

Working Draft 
Recommendations for ANSI/NIST ITL 1-2000 Iris Data Logical Record

This mandatory field contains the make, model and serial number for the iris capture device. It 

shall consist of three information items. The make of the iris capture device shall be the first 

information item followed by the “US” separator character, the model of the iris capture device, 

a “US” separator character, and the serial number of the iris capture device. Each information 

item shall be 1 to 50 characters. 

A.1.5 Field 17.005: Image Format (###) 

This mandatory field shall contain the image format code. It shall be used to specify the type of 

image format used. 

Code Description 

0 Undefined 

2 Gray Scale (mono) raw image format 

4 RGB (color) raw image format 

6 RGB gray scale (mono) JPEG image format 

8 RGB (color) JPEG image format 

A.1.6 Field 17.006: Horizontal Line Length (HLL) 

This mandatory field shall contain the number of pixels present on a single horizontal line of 

the transmitted image. 

A.1.7 Field 17.007: Vertical Line Length (VLL) 

This mandatory field shall contain the number of horizontal lines contained in the transmitted 

image. 

A.1.8 Field 17.008 Scale units (SLC) 

This mandatory field shall specify the units used to describe the image sampling frequency 

(pixel density). A "1" in this field indicates pixels per inch, or a "2" indicates pixels per 

centimeter. A "0" in this field indicates no scale is given. For this case, the quotient of 

HPS/VPS gives the pixel aspect ratio. 

A.1.9 Field 17.009 Horizontal pixel scale (HPS) 

This mandatory field shall specify the integer pixel density used in the horizontal direction 

providing the SLC contains a "1" or a "2". Otherwise, it indicates the horizontal component of 

the pixel aspect ratio. 

A.1.10 Field 17.010 Vertical pixel scale (VPS) 

This mandatory field shall specify the integer pixel density used in the vertical direction 

providing the SLC contains a "1" or a "2". Otherwise, it indicates the vertical component of the 

pixel aspect ratio. 

A.1.11 Field 17.011 Compression algorithm CGA) 

Working Draft 
Recommendations for ANSI/NIST ITL 1-2000 Iris Data Logical Record

This mandatory field shall specify the algorithm used to compress the image. An entry of 

“NONE" in this field indicates that the data contained in this record is uncompressed. The 

domain registrar maintains a registry of acceptable compression techniques and 

corresponding codes. 

A.1.12 Field 17.012: Bits Per Pixel (BPX) 

This mandatory field shall contain the number of bits used to represent a pixel. 

A.1.13 Field 17.013: Iris Image Quality (###) 

This optional field shall indicate the image quality value. This field is defined in ANSI-INCITS 

379-2004 – Iris Image Interchange Format. 

A.1.14 Field 17.014: Rotation Angle of Eye (###) 

This optional field shall indicate the rotation angle of the eye. For rectilinear images, rotation 

angle = round (65536 * angle / 360) modulo 65536. The angle is measured in degrees from 

horizontal. The value “FFFF” indicates rotation angle of eye is undefined. For polar images, 

entry shall be “FFFF”. 

A.1.15 Field 17.015: Rotation Uncertainty (###) 

This optional field shall indicate the rotation uncertainty. The rotation uncertainty is equal to 

round (65536 * uncertainty / 180). The uncertainty is measured in degrees and is the absolute 

value of maximum error. The value “FFFF” indicates uncertainty is undefined. 

A.1.6 Field 17.016: Image Properties (###) 

This optional field shall contain the image property code. It shall contain six information items. 

The first information item shall indicate the specific horizontal orientation. The second 

information item shall indicate the specific vertical orientation. The third information item shall 

indicate the specific scan type. The fourth information item shall indicate the specific iris 

occlusions. The fifth information item shall indicate the specific occlusion filling. The last 

information item shall indicate the specific boundary extraction. Each information item shall be 

one character and be separated from the next by the “US” separator character. These 

subfields are defined in ANSI-INCITS 379-2004 – Iris Image Interchange Format. 

Values for Horizontal Orientation shall be one of: “0” for Undefined, “1” for Base, or “2” for 

Flipped. 

Values for Vertical Orientation shall be one of: “0” for Undefined, “1” for Base, or “2” for 

Flipped. 

Values for Scan Type shall be one of: “0” for Undefined, “1” for Progressive, “2” for Interlace 

Frame, or “3” for Interlace Field. 

Values for Iris Occlusions shall be one of: “0” for Undefined or “1” for Processed. 

Working Draft 
Recommendations for ANSI/NIST ITL 1-2000 Iris Data Logical Record

Values for Occlusion Filling shall be one of: “0” for Zerofill or “1” for Unitfill. 

Values for Boundary Extraction shall be one of: “0” for Undefined or “1” for Processed. 

A.1.17 Field 17.017: Device Unique Identifier (###) 

This optional field shall contain a sixteen-byte string uniquely identifying the device or source 

of the data. This data can be one of: (1) Device Serial number, identified by the first character 

“D”, (2) Host PC Mac address, identified by the first character “M”, (3) Host PC processor ID, 

identified by the first character “P”, and (4) No serial number, identified by all zero’s. 

A.1.18 Field 17.018: Global Unique Identifier (###) 

This optional field shall contain a six-byte string to indicate a GUID – a globally unique 

identifier. 

A.1.19 Field 17.019: Image Transformation (###) 

This optional field shall specify the transformation type used in the record. A “0” in this filed 

indicates transformation type undefined, or a “1” indicates standard transformation type. 

A.1.20 Field 17.020-199: Reserved for Future Definition (RSV) 

These fields are reserved for inclusion in future revisions of this standard. None of these fields 

are to be used at this revision level. If any of these fields are present, they are to be ignored. 

A.1.21 Field 17.200-998: User-Defined Fields (UDF) 

These fields are user-definable fields. Their size and content shall be defined by the user and 

be in accordance with the receiving agency. If present, they shall contain ASCII textual 

information. 

A.1.22 Field 17.999: Iris Image (###) 

This field shall contain the CBEFF Biometric Data Block (BDB). It shall always be assigned 

field number 999 and must be the last physical field in the record. For example, 18.999: is 

followed by an iris BDB in a binary representation. 

A.2 End of Type-17 Iris Data Record 

For the sake of consistency, immediately following the last byte of data from field 17.999 an 

“FS” separator shall be used to separate it from the next logical record. This separator must 

be included in the length field of the Type-17 record. 

A.3 Additional Type-17 Iris Data Records 

Additional Type-17 records may be included in the file. For each additional iris record, a 

complete Type-17 logical record together with the “FS” separator is required. 

Working Draft