Video Spectral Comparator (VSC)


It is designed to satisfy the demands of immigration authorities, government agencies, and forensic science labs. The VSC includes advanced characteristics for the examination, comparison, and authentication of documents including passports and travel records, official letters and breeder documents, banknotes and cheques, works of art, and valuable artifacts through the detection of imperfections.

Video Spectral comparator comprises of the following:
• Laser-Induced Breakdown Spectrometer
• Computer
• Monitor

VSC is an integrated composite system comprising of cameras, various light sources which include IR, Laser, UV, etc., and filters that assist in the comparison of questioned documents.


VSC is a general workstation and casework management system for document examiners featuring the following:

1. Hi-Fi Imaging Technology: An optical system that reduces spatial distortions and chromatic aberration throughout the entire magnification range offer excellent image quality.

2. High-Resolution Imaging System

3. Full Range Light Source: It involves incident and transmitted ultraviolet to infrared plus high-intensity illumination for the examination of Infrared Fluorescence of inks.

4. Graphic User Interface: Innate, on-screen control method permits the operator to operate the system more easily. Magnification, light sources, filters, image analysis, and image processing functions are selected from simple on-screen icons using a mouse.

5. Multiple Laser Images (MLI): MLI and changeable Laser Images can be viewed using the VSC’s sidelights. Alternatively, the VSC range of hologram imaging LED’s can be used giving great versatility.

VSC updated software is integrated with the document database system (with a single-user license) that permits the operator to create their database and to obtain and present data from the Keesing reference database of security documents. Keesing is a reference database of security documents (i.e.) Passport, ID card, Driving license from 180 countries, comprising images and data.

VSC is one of the latest systems incorporating advanced technology and integrated system in the field of questioned documents. It is an extremely adaptable system. Visual spectral comparator is a complete digital imaging system implementing the questioned document examiner with a wide range of facilities for detecting variations on altered and counterfeit documents.

VSC is a comprehensive digital imaging system combining high-resolution optics and multi-spectral illumination with a great software package that involves tools for image enhancement and decoding digitally encrypted data. Access to optional reference databases enables comparisons with authentic security documents.

Specifications in VSC

• Digital Imaging
• High-resolution scientific-grade digital camera
• Zoom magnification range of approximately x1.5 to x170 (+/- 6%) on the standard 75cm (30inch) display monitor


• Complete control of VSC system hardware
• Image processing, comparison, and analysis
• Hyper pectoral imaging module
• Seamless integration with Document and Banknote databases Comprehensive casework management
• Automated examination routines
• Interactive tutorial


• The VSC consists of the main unit and a PC system. The main unit is a square box with 3 covers.

• In the main unit, one has a high-resolution CCD fire wire color camera with sensitivity from 360 nm to 1100 nm, different light sources, and optical filters as well as a trans-light panel.

• The panel is situated in the middle of the document platen. Under the panel is light sources that can illuminate the document from below.

• The document platen in itself is 650 mm x 650 mm while the trans-light panel is 235 mm x 175 mm. In the VSC there is also a high-resolution grating spectrometer.

• This can examine light from a small region in the document. As part of the VSC, machinery is a 30 inches screen and a Windows-based PC system.

Light Sources And Their Uses

The VSC has four distinct light sources.

• The first light source is incandescent filament lamps and has a range from 400 nm-1000 nm.

• These lights are used in the VSC when one uses the functions of a flood, transmitted, spot, and side lighting.

• The LED lamps have a wavelength from 400-700nm. The VSC offers three varieties of UV light. This is with 365 nm (UV-A), 312 nm (UV-B), and 254 (UV-C) peak wavelengths.

• A function that uses narrow-band illumination to trigger fluorescence. This illumination is in the IR region above 800 nm and lacks visible light.

• The VSC offers three different kinds of transmitted light.

• These light sources are located underneath the trans light panel.

• Here transmitted UV light or transmitted broadband illumination illuminates either the entire panel or a single spot.

• Diffracted lighting is a function that illuminates the document from different directions, and is normally used to see Optically Variable Devices (OVD).

• The side lighting is also a broad band-illumination. There are two lamps, one on the left-hand side and one on the right-hand side of the text platen. These can be used individually or they can both be on at the same time.

Coaxial light is a different function the VSC offers. Coaxial light is a light that is perpendicularly on the document. Coaxial light shows retro-reflective features in security documents, which are often used to prevent forgeries. Such retro-reflective features are hidden under normal light but exposed when the incident light is exactly coaxial to the angle of view.

The VSC also has a filter instrument panel. With this, the filters to be used in the camera and the spot lamp while using different functions can be chosen. This can decide if the whole range of the incandescent lamps of 400 nm-1000 nm will be measured if only the visible light range will be let through the filter, or the operator can choose specific cut-off wavelengths.


• The VSC offers micro spectrometry with a resolution of up to 9 nm.
• The spectrum screen shows a chromaticity chart and a spectral graph after a spectrum has been recorded.
• In the spectral graphs, one can read the plots of light intensity versus the wavelength from 400-1000 nm.


• Reveal Latent Images and Watermarks:
Latent images and watermarks are a commonly used security feature on banknotes worldwide. A latent image is visible only when viewed at an acute angle under reflected light and the watermark is viewed under transmitted light.

• Anti Strokes Illuminator

• Examining UV activated security features VSC is designed for the visual examination of Questioned Documents and Security Documents.

• It is used by immigration authorities and forensic laboratories.

• It is effective on all types of passports and identity cards.

• It helps to detects alterations and counterfeits.

• It reveals covert security features.

• It provides documentary evidence for prosecutions.

• It helps generate security alerts.

• It maintains comprehensive passport and banknote reference databases.

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