If you have ever had the opportunity to sit down with Dr. Joel Trussell, you will quickly see that he has a passion for digital imaging. Dr. Trussell, Professor of Electrical and Computer Engineering at North Carolina State University and Co-Author of Fundamentals of Digital Imaging (Cambridge University Press, 2008), along with Dr. Michael Vhrel, a Color Scientist from Artifex Software, Inc., wanted to acquaint people on how digital imaging is affecting them. That’s where his new "Fundamentals of Digital Images" three-day course came in this summer.

"The goal of this short course, and the Digital Imaging Class (ECE558) being offered at NCSU, is to show the student how to accurately record, process and display images," says Dr. Trussell. "There is no way to accurately reproduce an image unless the data from which you are working is accurate to begin with. We teach the definitions of the quantities that matter and how to record them."

What do people know about how you capture an image? What goes on inside an image and scanner? How do we store that data? How do you display this image so that it’s an accurate portrayal of the original? These are just a few of the questions that were answered in this course. "More and more, images are going online and more people are dealing with them. And you want to have the best interpretation of them." In the class, students studied the formats used to store and display images — and how each affect the quality of digital images — as well as the science behind (and practical application of) the calibration of scanners, cameras, flat-panel displays and printers.

"The accurate reproduction of an image requires knowing the characteristics of the display device, including what color it can produce and how to produce them." says Dr. Trussell. Between the capture and the display is the processing. And typical processing includes translating raw values into colorimetric values that can be used by anyone in the world, storing and transmitting data between devices so they can display the same image accurately. This is even despite different hardware and calibration of input and output devices. This will allows for the image data to be interpreted appropriately.

The image of Lena is used by many in industry and academia to test image coding methods. A typical copy of Lena is shown in Figure 1. You can see many reproductions of Lena by searching "Lena image processing" in Google Images. Dr. Trussell says "The images vary tremendously because the original data was not capture accurately and there is no conversion to a standard display format so that all the images, starting from the same data, would look the same."

The second image (Figure 2) is very nearly how Lena should look. This image was produced by capturing an original print of the image with a calibrated scanner and translating the data to a standard format recognized by most displays. "For librarians and archivists, it is important to preserve images and documents accurately, so they can be studied by researchers many years in the future", states Dr. Trussell.

This workshop was a semester’s worth of information distilled from ECE558X "Digital Imaging Systems", a Graduate Level course being offered at North Carolina State University that has been geared toward engineers that are working in the digital imaging field. Dr. Trussell saw a need for a curriculum designed for those at the document level — such as librarians and archivists who require accurate acquisition of imaging — however the class was open to anyone with the sole requirement of having worked with images previously. The workshop was offered in July on North Carolina State University’s Centennial Campus and due to its popularity is expected to be offered again during spring break or next summer.

For more information visit the Fundamentals of Digitial Imaging Website.