A Conversation with the People Behind the IDMS
The Information Display Measurements Standard (IDMS) represents years of work by many individuals in the display industry who form the International Committee for Display Metrology (ICDM). The standard would not exist in its present form, however, without the contributions of ICDM committee chair Joe Miseli and IDMS Editor Ed Kelley. Both Miseli and Kelley recently described the challenges and highlights of the process.
Compiled by Jenny Donelan
Editor — Ed Kelley IDMS Committee Chair — Joe Miseli
THE International Committee for Display Metrology (ICDM) standards project began in 2007 as a replacement for the VESA Flat Panel Display Measurement (FPDM) standard, which the same authors wrote. It became a monumental effort that redefined the standards for the optical metrology of displays. In June of 2012, the Information Display Measurements Standard (IDMS), containing approximately 140 different display measurements, was released as both a free download and a hardcopy for purchase (see sidebar for availability).
In the words of the ICDM literature: “The IDMS is the “Go-To” document for standard measurement procedures to quantify electronic- display characteristics and qualities. It is the culmination of years of effort by engineers and scientists across dozens of organizations to codify the science of display measurement, explain some of the difficulties associated with making measurements, and offer solutions to help make the measurements properly. The IDMS has benefited from the expertise of the ICDM, consisting of display metrologists, electrical, mechanical, software, and optical engineers, physicists, vision scientists, and many other display-related disciplines.”
Hundreds of individuals in the field of displays contributed to the project. Key among them were ICDM committee chair Joe Miseli and Editor Ed Kelley. Information Display recently spoke with Miseli and Kelley about the process and how the IDMS will evolve in the future.
ID: What were the biggest technical and scientific challenges that needed to be addressed to complete the IDMS?
Kelley: The biggest challenges were mostly editorial in nature. I found that I had to rewrite quite a bit of the material to keep it within the style and philosophy of the document.
Miseli: Some of the technical difficulties we encountered had to do with the mass of this project. There are so many measurements and many of them are detailed to the point where other standards organizations might take one of them and turn it into a full-blown standard on their own. In addition, technically we had plenty of resources within our group, but it was sometimes tough for everyone to find the time to work on the project due to the
level of detail and time required to produce the quality of metrology per the ICDM’s exacting standards.
ID: What’s new in the document, as compared to its former iteration as the FPDM?
Kelley: Of course, there was a lot of material to add to keep pace with industry progress. Stereoscopic 3-D displays were a big addition. We also added front projection and front-projector screens, and a chapter on motion artifacts. Another new chapter is on touch-screen and surface displays. Gray and color scales have been greatly expanded, with more ways to analyze the gamma or tone curves. The uniformity chapter was expanded to include the use of tristimulus imaging cameras. Viewing-angle measurements received additions, with emphasis on perception, color, and providing single-number metrics. The temporal-measurements section was improved, and many additions were made to the reflection chapter. A great deal of reflection research had been accomplished since the FPDM and this was included in the new document.
ID: What has been the feedback/industry reaction so far?
Kelley: A number of people have mentioned that it was a monumental task and that they appreciated it.
Miseli: Reactions have been extremely positive. We’ve had thousands and thousands of downloads. As you know, we made it for free, which was part of our charter coming into SID. The download is free – there is a charge for the printed copy. I will say there’s plenty of merit to having a printed copy. It’s the kind of document that lends itself to being held in your hand, where you can actually refer to the pieces that you want. It’s printed in full color.
ID: For companies looking to adopt the IDMS, what kind of investment is needed and how accessible are the methods contained in the standard?
Kelley: I have a fully functional laboratory in my basement. My total investment is around $200K, which doesn’t include $45K for the spectroradiometer. If one were to limit acquisitions to only what is absolutely needed, you could get started for much less. That is the intent of the document, to keep everything as simple as possible.
Miseli: We offer various ways to make luminous measurements, for example, that a person could do with virtually any piece of professional equipment so that they do not need to invest in a specific type of equipment that can be pretty pricey.
ID: So, people do not need to build an entire lab?
Miseli: No, but there are things that people need to have in place, like a darkroom. They don’t necessarily have to have extraordinary XY stages and moving devices and so forth. It can be as simple as a luminous measurement device on a tripod for many of the basic measurements. We even have some very fundamental assessments that can be done visually, just to give people an overview of what’s going on with their displays, even if they do not have equipment. However, to maximize the value of the standard, one would require more sophisticated and higher- end equipment and software support, which could become rather pricey, depending on the amount of sophistication and automation that one chose to utilize.
ID: Once you’ve caught your breath, what’s in store for the next version of the IDMS?
Kelley: We can expect that there will be additions to all the chapters. Head-mounted and near-to-eye (NTE) displays will likely be added as a chapter, as will transmissive displays. Flexible displays need to be added, especially in the reflection chapter. Reflective displays may also be added as a separate chapter with connections to the reflection chapter. We can expect some contributions in the way of creating composite metrics based upon the existing metrology in the document; such metrics could be useful to those who consider the vision impaired. That could end up being a separate chapter as well.
Miseli: The next version should be ready a couple of years from now. It should have at least 10–25 new measurements in it.
ID: What aspect of the document are you most pleased with?
Kelley: The graphics are by and large improved. The color and gray scales section in particular is rather nicely detailed. I’m pleased with how the document looks overall. This is an example of how to not waste paper by getting everything into a small space that’s easy to read and easy to understand. It’s not a spaghetti document: You do not have to search here and there to find everything you need to know. The downloadable version is a PDF that’s searchable; it’s really nice.
Miseli: The document is a complete standard, with all measurements and expanded reference materials within a single cover. The task for getting a document of this scope completed was very challenging, and there were a number of skeptics who doubted that it would ever be completed, as well as others who often suggested making compromises. Yet we persisted and got it done – properly and to our expectations. I’m pleased that we were able to get so many tests and metrology chapters done which address the needs of today’s displays, such as for motion artifacts, 3D stereo, projection, touch screens, reflection, temporal measurements, viewing angle, etc. Yet, we maintain high quality and clear and concise presentation of the standards methods as well as possible. We have nearly every measurement needed to evaluate displays today in a full color, very-high-quality document, all within a single cover, due to the tremendous expertise and effort of many, many experts who contributed. This document is a great work which is a worthy representative of the first standard from SID and the ICDM. •