"WSQ image library" for Linux 64-bit (version 2.0)
FBI certified WSQ implementation number:
11282 (scanned certificate)


WSQ image library adds the power of WSQ (FBI's Wavelet Scalar Quantization) file format to your software projects using only a few lines of code.
The library also supports other graphic file formats and allows conversion between them.

Free WSQ Viewer demonstrates capabilities of WSQ image library.

Importance of WSQ format

Electronic fingerprints submitted to the FBI either through Integrated Automated Fingerprint Identification System (IAFIS), or Electronic Fingerprint Image Print System (EFIPS) may not be compressed with any technique other than WSQ.

Licensing of WSQ image library

How long does the license last?
Buy once, use forever!
The license is perpetual. There is no annual fee. There is no timing limitation.
“WSQ image library” is NOT a subscription.
All future updates are included with your one-time purchase at no additional charge.
You will get all updated versions of “WSQ image library” without any additional payment.

Price of WSQ image library

Licensing of “WSQ image library (for Linux 64-bit)” is available in two ways:

1) runtime free/royalty free. This means when you buy such a license, your organization/company can run “WSQ image library (for Linux 64-bit)” on unlimited number of computers.
WSQ image library (for Linux 64-bit) runtime free license costs 505.00 U.S. dollars.

2) licensing individual computers. The price for the first license (single developer license) is 126.00 US dollars, and the price for additional client licenses is 19.00 US dollars per license. One license means one computer.
Let you illustrate with the example.
Suppose you want to run “WSQ image library (for Linux 64-bit)” on six(6) computers.
Then the price will be:

126.00 US dollars (first license) + 19.00 US dollars x 5 (five additional client computers) = 126.00 + 19.00 x 5 = 221 US dollars.

Android, Windows 32-bit, Windows 64-bit, Linux 32-bit, Linux 64-bit and macOS 64-bit versions of WSQ Image Library are considered separate products and each has its own pricing.
To order "WSQ image library (for Linux 64-bit)" please click here

WSQ image library (for Linux 64-bit) specifications

Table 1 Format of WSQ image library

Operating systemLinux 64-bit (x64 platform)
Library formatShared Library (*.so)
Format of exported functionsC language
Calling convention
of exported functions
Calling conventions
of exported functions
available through additional
wrapper DLL interface
Internal engineC++

Table 2 Supported formats for reading

WSQFBI's Wavelet Scalar Quantization
BMPWindows Bitmap Graphics
TIFFMacintosh Tagged Information File Format images
TIFPC Tagged Information File Format images
JPG, JPEGJoint Photographic Experts Group images
PNGPortable Network Graphics images
GIFCompuserve Graphic Interchange Format images
TGATruevision Targa Graphic images
PCXZSoft Paintbrush images (PC Paintbrush Bitmap Graphic)
PSDPhotoshop images
CELAutodesk images / Animator Graphic (FLC and FLI formats)
IFFAmiga Bitmap Graphic (8 bits)

Table 3 Supported formats for writing

WSQFBI's Wavelet Scalar Quantization
BMPWindows Bitmap Graphics
TIFTagged Information File Format (no LZW compression)
PNGPortable Network Graphics
JPGJoint Photographic Experts Group
TGATruevision Targa Graphic

Table 4 Functions available in the library

int ReadImageFromFile(const char* fileName, int* width, int* height, unsigned char** imageData)Creates an image data array from an image file. The extension of the file name determines the file type. Returns an 1 if successful, 0 otherwise.
int SaveImageToFile(const char* fileName, int filetype, int width, int height, unsigned char* imageData)Saves the contents of an image data array to a file. Returns 1 if successful, 0 otherwise.
"filetype" denotes integer with possible values:
1 - WSQ
2 - Windows BMP
3 - TIFF
4 - PNG
5 - JPEG
7 - Targa
char* GenerateSerialNumber()Generates serial number for registration of WSQ image library.
int UnlockWSQLibrary(char* authorization_code)Registers WSQ image library on the computer. Returns 1 if successful, 0 otherwise.
void WriteWSQ_bitrate(double bitrate)Sets current WSQ bitrate. For example 0.75, 2.25 (-1.0 if unknown).
double ReadWSQ_bitrate()Reads current WSQ bitrate. For example 0.75, 2.25 (-1.0 if unknown).
void WriteWSQ_ppi(int ppi)Sets current WSQ ppi (pixels per inch). Value "-1" is used for unknown ppi.
int ReadWSQ_ppi()Reads current WSQ ppi (pixels per inch). Value "-1" is used for unknown ppi.
void WriteWSQ_comment(char *comment)Sets current WSQ comment text.
char* ReadWSQ_comment()Reads current WSQ comment text.
void WriteTIFFcompression(int tiff_compression)Sets the TIFF compression type. Available options are:
0 - NONE
1 - ZIP compression
(if ZIP compression is used, you also need to set TIFF "predictor" parameter)
2 - MACINTOSH compression
void WriteTIFFpredictor(int tiff_predictor)Sets the TIFF ZIP compression predictor value.
int WSQ_decode_stream(unsigned char *input_data_stream, const int input_stream_length, unsigned char **output_data_stream, int *width, int *height, int *ppi, unsigned char **comment_text)Decodes memory stream (memory block) from WSQ format into uncompressed format. Returns 1 if successful, or error code otherwise.
int WSQ_encode_stream(unsigned char *input_data_stream, const int width, const int height, const double bitrate, const int ppi, char *comment_text, unsigned char **output_data_stream, int *output_stream_length)Encodes memory stream (memory block) from uncompressed format into WSQ format. Returns 1 if successful, or error code otherwise.
int ReadWSQ_implementation_number()Reads WSQ implementation number.

WSQ format description

In the USA, fingerprints have traditionally been collected on cards, each card containing the inked impressions of all ten fingers. The U.S. Federal Bureau of Investigation's fingerprint database began in 1924 with a cataloged collection of 810,188 cards. By the start of World War II, this collection had grown to over 10 million cards, and by 1946 had reached over 100 million cards.

In 1995 this collection was contained on over 200 million cards stored in filing cabinets occupying one acre of floor space in the J. Edgar Hoover building in Washington D.C. and archive size was increasing at the rate of 30,000 to 50,000 new cards per day.

Digitization of fingerprint cards seemed to be the most obvious choice and the project named FBI's Integrated Automated Fingerprint Identification System (IAFIS) was started to cope with the design and implementation of a national standard for collecting, encoding, storing, and retrieving digitized fingerprint images. According to the FBI standard fingerprints are stored as 8-bit grayscale images. Each fingerprint card, when digitized at 500 dpi requires about 10 Mbytes of storage. The FBI's entire collection would therefore consume two petabytes (2,000,000,000 megabytes) of electronic storage space.

The need for an effective compression technique was then very urgent. Unfortunately, neither the well-known lossless methods nor the JPEG methods were found to be satisfactory. Most lossy compression methods, such as JPEG, discard the smallest (highest frequency) details in images, and at higher compression ratios unacceptably distorts the image. Contained within fingerprints are tiny details that are considered admissible points of identification in a court of law. To JPEG, these details may be regarded as noise and removed. The JPEG quantization matrix also allows blocking artifacts to occur in the image at compression ratios above about 10:1. Shifting bits to the high frequencies to preserve small details will only make the blocking worse.

Lossless compression methods, such as LZW and JBIG, cannot achieve the high compression ratios of WSQ on fingerprint data, with 2:1 typically being the best.

A new compression technique (with small acceptable loss), called Wavelet Scalar Quantization (WSQ) was developed and it became the FBI standard for the compression of 500 dpi fingerprint images.

WSQ is a lossy compression method that is well-suited for preserving the very high resolution details of grayscale images while maintaining high compression ratios of typically 12:1 to 15:1 on images that have not undergone "quality enhancements" (such as histogram equalization) to improve the appearance of the image.

Table 5 WSQ file format specifications

NameFBI's Wavelet Scalar Quantization file format.
Also known as: FBI Fingerprint Format or FBI WSQ
ApplicationThe standard file format used by the FBI for storage and interchange of grayscale fingerprint images
OriginatorFBI (U.S. Federal Bureau of Investigation)
Colors8 bit grayscale
CompressionWavelet Scalar Quantization
Maximum image size64K x 64K
Multiple images per fileNo

Adding WSQ image library to your software project

Using WSQ image library is very easy. Only 2-3 steps and a few lines of code are needed. Several examples are provided below.
GNU C Compiler GCC
Sun Java

GNU C Compiler GCC

Step 1
Load WSQ library and declare its functions. Add following lines to your code:

#include <stdio.h>
#include <dlfcn.h>
void* handle;
typedef int (*_ReadImageFromFile)(const char* fileName, int* width, int* height, \
                                                     unsigned char** imageData);
_ReadImageFromFile ReadImageFromFile = 0;
typedef int (*_SaveImageToFile)(const char* fileName, int file_type, int width, \
                                        int height, unsigned char* imageData);
_SaveImageToFile SaveImageToFile = 0;
typedef int (*_RegisterWSQ)();	
_RegisterWSQ RegisterWSQ = 0;

handle = dlopen ("./libWSQ_library64.so", RTLD_LAZY);
ReadImageFromFile = (_ReadImageFromFile)dlsym (handle, "ReadImageFromFile");
SaveImageToFile = (_SaveImageToFile)dlsym (handle, "SaveImageToFile");	
RegisterWSQ = (_RegisterWSQ)dlsym (handle, "RegisterWSQ");

Step 2
Call and use WSQ library functions:

ReadImageFromFile(fileName, &width, &height, &data);
SaveImageToFile(fileName, file_type, width, height, data);

Step 3
Unload WSQ library. Add following lines to your code:

dlclose (handle);

To download GNU C Compiler GCC 5.4.0 sample project click here

Sun Java

Click here for important notes for Sun Java developers

Step 1
Add declarations of WSQ library functions using JNIEXPORT wrapper interface:

public static native int[] ReadImageFromFile(int[] dimension, String fileName);
public static native void SaveImageToFile(int[] data, int width, int height, String fileName, int type);
public static native void RegisterWSQ();

Step 2
Call and use WSQ library functions:

int[] data = WSQ_Demo.ReadImageFromFile(dimension, fileName)
WSQ_Demo.SaveImageToFile(pixels, width, height, fileName, type)

To download Sun Java (Java SE Development Kit 8u151 with NetBeans IDE 8.2) sample project click here


Step 1
Add declarations of WSQ library functions:

function ReadImageFromFile (const file_name: PCHAR; width: PInteger; height: PInteger;
imageData: PPCHAR): Integer; cdecl; external 'libWSQ_library64.so' name 'ReadImageFromFile';
function SaveImageToFile(const filename: PCHAR; filetype: Integer; width: Integer;
height: Integer; imageData: PCHAR):Integer;
cdecl; external 'libWSQ_library64.so' name 'SaveImageToFile';
function RegisterWSQ():Integer; cdecl; external 'libWSQ_library64.so' name 'RegisterWSQ';

Step 2
Call and use WSQ library functions:

ReadImageFromFile(PCHAR(open_dialog.FileName), @width, @height, @imagedata);
SaveImageToFile(PCHAR(save_dialog.FileName), save_dialog.FilterIndex,
OutputImage.Picture.Bitmap.Width, OutputImage.Picture.Bitmap.Height, imagedata);

To download Lazarus 1.6 sample project click here


Step 1
Click here for important notes for PHP developers

Step 2
Call and use WSQ library functions:

//converts image from WSQ format to JPG format
$image1 = wsq_read_image_from_file("./sample_image.wsq");
wsq_save_image_to_file($image2, $output_fileName, 5); //save image as JPG

To download PHP 4/5/7 sample project click here

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