Image Smiths VeriLUM 4.3 User manual


VeriLUM® 4.3

Color and Grayscale Video Display Calibration,

Verification and Tracking,

Acceptance Testing


IMAGE Smiths,Inc.

19508-C Amaranth Drive, Germantown, MD 20874

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This User Guide describes installation and operation of VeriLUM® Version 4.3.

Revision Date: November 1, 2001

Copyright © 1999 by IMAGE Smiths, Inc. All rights reserved.

Copyright permission granted for display of the SMPTE Test Pattern Rev. 10/ 6/83 by the Society of Motion Picture and Television Engineers and for the CIE 1931 Chromaticity Diagram by Joe Kane Productions, Inc.

Trademarks, service marks, and other registered names are hereby acknowledged to be the property of their owners: Adobe Systems, Incorporated; Appian Graphics; Astro Design, Inc.; BARCO, Inc.; Dicom; DOME Imaging Systems, Inc.; Intel Corporation; Matrox Electronic Systems, LTD; Microsoft Corporation; National Display Systems; National Electrical Manufacturers Association; NEC; Sequel Imaging Corporation; and Tektronix, Inc.

Companies and organizations should be contacted for complete information regarding trademarks and other registrations.

VeriLUM is compliant with year 2000 standards and will not be affected by dates occurring before, during, or after the year 2000.


Table of Contents


1.0Getting Started

1.1System Requirements

1.2Installing VeriLUM

1.3Running VeriLUM

1.4Uninstalling VeriLUM

2.0Operating VeriLUM

2.1Using VeriLUM for Acceptance Testing

2.2Using VeriLUM for Calibration to a Luminance Response Model

2.3Using VeriLUM for Verification and Tracking

2.4Color Adjustments

2.5Plot Results

3.0Technical Notes

3.1White Level and Black Level Settings

3.2Selecting Luminance Measuring Device

3.3Number of Luminance Measurements

3.4Data File Format for User Defined Luminance Response Model

3.5Registry Entries and Downloadable Gamma Ramps

3.6CIE Chromaticity Coordinates

3.7Color Temperature

3.8Using VeriLUM with Multiple Color Monitors on a Desktop

4.0Calibration Scenarios

4.1One or More Grayscale Video Displays and BARCO or DOME Video Card

4.2Windows 95/98/NT/2000 and Color Monitor and Downloadable Gamma Ramp Video Card

4.3Windows 95/98/NT/2000 and Color Monitor and Non-Downloadable Gamma Ramp Video Card



VeriLUM® 4.3 is a tool for ensuring consistent color and grayscale video display performance. In the past this function has been the province of the video card vendors and the video monitor manufacturers. More recently the responsibility for assuring the quality of soft copy display has been placed exactly where hard copy quality assurance resides: in the hands of the end user. This means the end user must be able to make reproducible measurements of the video display performance and interpret and act on the results.

Our goal is to make it easy and efficient to judge when a video display system is continuing to function normally or needs adjustment or replacement.

One use of VeriLUM is acceptance testing of a video display system prior to signing off on procurement paperwork.

VeriLUM also provides a quick visual check for the user. A SMPTE test pattern and a VeriLUM test pattern can be displayed on each video monitor that is part of the desktop. If the grayscale range and stability is adequate for each monitor, if the geometry and focus are acceptable, and if all of the monitors have essentially the same look-and-feel, then the video system is ready for use. If one or more of the video displays is in need of adjustment then maintenance can be requested.

For the quality assurance specialist interested in tracking consistent performance over time, a rapid set of measurements of the display luminance is made and an index is computed for each video monitor. These measurements take about 30 seconds per monitor and the history chart can be printed when hardcopy documentation is required. The computed index indicates how well the video system matches a specific luminance response model. Even if the “natural gamma” of the monitor is used, it is still possible to track the computed index, the white level, and the black level, over time.

In addition, for color monitors, the correlated color temperature and chromaticity coordinates of the white level and the luminance values for the red, green, and blue primaries are tracked.

VeriLUM also can be used to perform gamma correction in conformance with the DICOM® Part 14 Grayscale Standard Display Function or a user specified gamma model or any other user defined luminance response model. Loading a lookup table at system startup time is possible if a grayscale video board is used that has the facility for on-board gamma correction. Currently VeriLUM provides on-board gamma correction using BARCO, DOME, Appian, and Astro grayscale video boards. If the operating system is Microsoft Windows 95 or 98 or 2000 and if the color video card supports downloadable gamma ramps then VeriLUM will use that capability, and download the gamma ramp onto the video card automatically. If the operating system is Windows NT, then a few video cards support downloadable gamma ramps using non-standard driver calls (e.g., Matrox G200/G400/G450 and Appian Jeronimo 2000).

For color monitors two techniques are provided for adjusting the color presentation. If the operating system and video card support downloadable gamma ramps, then VeriLUM can automatically adjust the red, green, and blue (RGB) relative gains in order to achieve a user specified color temperature. However, even if downloadable gamma ramps are not supported, guidance is provided about the appropriate RGB luminance levels needed in order to achieve a desired luminance level and color temperature.


A VeriLUM luminance pod must be connected to the PC each time the software is run. There are two different VeriLUM pods: color and grayscale. The same software package works with either pod type. A grayscale pod must be used with grayscale monitors. The grayscale pod can be used on color monitors, but the chomaticity measurement features will not be available. The color pod provides chromaticity and luminance measurements on color monitors.

Please note that, unlike most PC software packages, VeriLUM software can be installed on as many workstations as desired; no additional licenses are required. This allows a VeriLUM pod to be taken from workstation to workstation to perform measurements. The VeriLUM pod uses a serial communications port on the PC and thus a simple extension cable from the serial port to the front of the PC minimizes the aggravation of hunting around behind the PC for the proper connector.

In summary, VeriLUM provides a simple, effective tool for performing calibration, tracking, acceptance testing, and visual verification of a color or grayscale video display system.


1.0Getting Started

1.1System Requirements

VeriLUM requires an Intel PC; Microsoft Windows 95, 98, NT 4.0, or 2000 Operating System; and a video card capable of at least 800 X 600 pixels with a minimum of 256 colors (24 bit or 32 bit true color is highly recommended) or a grayscale video board (BARCO, DOME, Appian, or Astro). Administrator privileges are required to install VeriLUM software in Windows NT 4.0 and Windows 2000.

1.2Installing VeriLUM

VeriLUM software is shipped on a CD-ROM. Place it in the CD reader, double-click the CD drive icon, and double-click the VeriLUM43_Install.exe icon with the left mouse button. The installation script will verify the minimum system requirements, create the necessary folders and icons, and install the program files and ancillary files.

The install process uses the Microsoft Installer Technology. If the Installer Engine is not already on the PC, it will be included in the install process and it may be necessary to restart the PC during and/or after the install procedure.

This User Guide is included on the CD in both Microsoft Word format and in Adobe Acrobat PDF format. Please print as many copies as you need. In addition, this User Guide is copied to the folder in which VeriLUM is installed so it is available on each PC where VeriLUM is used.

1.3Running VeriLUM

[ Note: With one exception, VeriLUM uses the left mouse button exclusively. Thus all references to clicking imply left mouse button clicks. The exception is a right mouse click to toggle the gamma correction on and off in VeriDisplay (see Section 2.2). ]

Connect a VeriLUM pod (color or grayscale) to an active COM port on the PC. Auto-detection of the COM ports is performed. Click on Start / Programs / VeriLUM and then click on the VeriLUM icon.

Normally the VeriLUM main dialog box appears as shown in Figure 1

However, the first time VeriLUM is run, a configuration dialog box appears (see Figure 2). Please specify the number of video monitors comprising the desktop. This ensures that the video measurements are made in the center of each monitor and not the center of the desktop. Click the OK button to activate the main dialog box of VeriLUM.

The EXIT button returns control to the desktop.


The Configuration dialog box has two buttons in the upper right-hand corner that we use to select the type of VeriLUM pod being used (Grayscale or Color) and the display device being used. See Figures 2A and 2B.

The default selections are to set up VeriLUM to run with a grayscale pod and on a CRT.

If you have a National Display Systems Nova Series LCD flat panel display running on a Matrox G200 MMS video card, then click that button. The other choices are for a National Display Systems Vector Series LCD flat panel and a NEC 1830 LCD flat panel.

Other flat panel vendors and models will be added in the future.

A percent surround value can also be specified. Once specified, this value is used for all luminance measurements, in particular all luminance measurements for determining the DICOM Part 14 gamma correction table. The default value is 20%.

All other buttons are described in Section 2, Operating VeriLUM .

When using VeriLUM with a color monitor and an operating system and video card that permits downloading gamma ramps, a Task Bar Status Area Icon appears. Resting the mouse pointer on the icon activates the message “Gamma Correction On Off.” Clicking on the icon initiates a dialogue to toggle the gamma correction lookup table on the video card between gamma correction and no gamma correction. This allows a user to choose to view color images without gamma correction of the gray scale and then to choose to view grayscale images with the gamma correction turned on.

1.4Uninstalling VeriLUM

An icon for removing VeriLUM is in the Control Panel under the Add/Remove Programs function. If you click the VeriLUM item in the program list, you will be asked whether you are certain you want to remove the VeriLUM application. If you answer YES then all files and icons created as a part of the install process will be removed. Files created during the operation of the VeriLUM software will not be removed.


Image Smiths VeriLUM 4.3 User manual

FIGURE 1. VeriLUM Main Dialog Box


FIGURE 2. VeriLUM Configuration Screen


Figure 2A. VeriLUM Luminance Measuring Device Screen

Figure 2B. VeriLUM Display Device Screen


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