Rykowski R.,Radiant Imaging
Light and Engineering | Year: 2011
Measured light source models have been widely used in ray trace simulations for optical design for more than 15 years now, but to date the generated ray sets have not contained spectral information. In some limited cases, tristimulus measurements can be helpful, but most ray tracing software requires a specific wavelength assigned to each ray to enable full colour simulations of an optical system. This paper describes and tests various techniques for combining spectral measurements with either photopic or tristimulus imaging colourimeters to produce ray sets that contain a wavelength. These ray sets can generally be readily used by most raytracing software to refract and diffract rays more accurately through the optical system and to generate illuminance or luminance distributions that also include colourimetric information. Finally, the methods are tested with real light sources where spectral power distribution varies significantly spatially across the light source and/or as a function of angle.
Fusco R.,Radiant Imaging |
Petrillo A.,Radiant Imaging |
Petrillo M.,Radiant Imaging |
Sansone M.,University of Naples Federico II
Applied Magnetic Resonance | Year: 2013
The aim of this study was to identify, on the basis of simulated tracer kinetic data, the best subset of semi-quantitative features suitable for classification of dynamic contrast-enhanced magnetic resonance imaging data. 1926 time concentration curves (TCCs) of Type III, IV and V [according to the classification of Daniel et al. (Radiology 209(2): 499-509 (1998))] were simulated using the gamma capillary transit time model and the Parker's arterial input function. TCCs were converted in time intensity curves (TICs) corresponding to a gradient echo sequence. Seventeen semi-quantitative shape descriptors were extracted from each TIC. Feature selection in combination with classification and regression tree was adopted. Several acquisition parameters (total duration, time resolution, noise level) were used to simulate TICs to evaluate the influence on the features selected and on the overall accuracy. The highest accuracy (99.8 %) was obtained using 5 features, total duration 9 min and time resolution 60 s. However, an accuracy of 93.5 % was achieved using only 3 features, total duration 6 min and time resolution 60 s. This latter configuration has the advantage of requiring the smallest number of features (easily understandable by the radiologist) and not a very long duration (reduced patient discomfort). © 2013 Springer-Verlag Wien.
News Article | July 20, 2006
The original 2407WFP monitors had a problem with banding that turned out to be a firmware issue. If very specific patterns (such as DisplayMate’s test gradients) were sent to the monitor, the firmware could get confused and think it was a video feed and process the signal incorrectly, producing the color banding you see below: Our model is revision A02, and this newer firmware fixes that specific problem—mostly. There are three color-mode defaults in the monitor’s setup menu—Desktop, Multimedia, and Gaming. As long as you leave it in Desktop mode, the banding problem doesn’t pop up. In Multimedia or Gaming mode, it does. We’re not even sure what these modes do, besides tweak brightness and color values slightly. Just leave the monitor in Desktop mode, and you’re good to go. At default settings, the 2407WFP delivered about 300 cd/m2 of brightness, and full black was a reasonable .29 cd/m2, giving us an average contrast ratio of 1039:1—actually in line with the advertised spec. Turning the brightness down to about 100 cd/m2, more comfortable for viewing in a darkened room, the black levels didn’t decrease much, and the contrast ratio dropped to about 350:1. That’s still not bad for a display configured for viewing in a dark room, especially since this is a desktop PC monitor and is made to be used in somewhat more bright environments. Still, we would like to see the dark level pushed down to .20 cd/m2 or less. To the naked eye, backlight uniformity looks perfectly fine; color and brightness is uniform all over. Under closer examination with the Radiant Imaging device, we confirm what our eyes told us. At full white, the backlight is slightly biased toward the left side of the screen, but stays pretty consistent all over. At full black, we see one of the most uniform isoplots we’ve ever seen on a desktop LCD monitor. It’s a bit hotter in the upper right, but the differences are quite minor. In short, objective testing shows this to be one of the most uniform LCD desktop monitors we’ve seen. The PC Magazine response time, where a box is moved quickly around the screen at a regular speed (we tweak both box and background colors) showed minimal tearing and almost no ghosting. Our subjective tests during games backed it up: This monitor shows very little blurring or ghosting. Continued…
News Article | July 24, 2006
The VP2330wb comes out of the box with contrast set to 70% and brightness at 100%. The on-screen menu offers several color temperature settings as well as custom color adjustments, with the default at 6500K. This is where we took our initial tests. Note that the color temperature tracks way above 6500K across most brightness levels. It only approaches the 6500K level at 100% brightness. We were able to dramatically improve this curve with some color calibration, though. So if you pick up this monitor, you’ll want to color-calibrate it. The primary colors CIE chart doesn’t look half bad. It’s a little off from NTSC standard, but that’s not at all uncommon—nor necessarily a bad thing—for PC monitors. Moving on to the RGB levels histogram, we see that the red and blue values are totally off base through most brightness settings. Green tracks pretty well throughout, but the other two primary colors only get into the reasonable range up above 90% brightness. By delving into the custom color menus, we were able to make massive improvements in both the color temperature and RGB level tracking from dark to bright levels. After making these manual adjustments, the color accuracy of the monitor was really quite impressive. Continued…
News Article | July 20, 2006
The 2407WFP comes out of the box with the brightness setting set to 50%, and true to most Dell monitors, adjusting it all the way up or down the scale had a pretty minor effect. The brightness control doesn’t actually adjust the backlight, unfortunately, so the best way to tweak the monitor’s brightness is by using your video card control panel. Color temperature tracked just above 6500K through most of the brightness curve, bumping up a bit down around the 10% brightness level. These are quite good out-of-the-box results, and it didn’t take much tweaking to improve it further. Looking at the CIE chart, we can see the new 24″ Dell is a bit short on blue, but this is typical of LCD monitors. It’s actually tracking the primary colors quite accurately at full brightness. If we look at the color tracking for red, green, and blue individually across the brightness range, we see that the 2407 by default runs a bit green and goes way outside the range on blue in the very dark areas. Believe it or not, this isn’t bad color tracking for a display’s default settings. A little tweaking of the color controls in the on-screen menu let us clamp down those values and get quite uniform color everywhere above 30% brightness. Continued…
News Article | January 5, 2006
Let’s take a look at the rated specs for the 3007WFP: The front view of the 3007WFP is quite plain. There’s a power button and two buttons, one with a “+”, the other a “-“. All three are flush with the bezel, in a departure from the more tactile buttons on other Dell displays. The two adjustment buttons on the front only adjust brightness. There is no on-screen display. In fact, this monitor has no image processing chipset built-in, unlike most desktop displays, and relies on the PC graphics card control panel to manage all settings. We’ll touch on that issue more in a bit. Note that the display has only a single, dual-link DVI input. You’ll need to use a graphics card that supports dual-link DVI. Dell includes a dual-link DVI cable with the monitor. This doubles the bandwidth available to the display, which is required to drive 4 megapixels. Most high-end and a few midrange cards now support dual-link DVI, including the GeForce 7800GT and GTX, plus the ATI X1600 and X1800 series graphics cards. The DVI input also supports HDCP content protection, for future use with Windows Vista as well as connectivity to digital set-top boxes and future high-definition optical drives. However, no high-definition input source supports more than 1920×1080 pixels. The display has four built-in, powered USB ports, plus an upstream port for connecting to the PC. Also built-in are two slots for inserting memory cards. The 3007WFP supports Compact Flash (all types), SD, MMC, Memory Stick, and Smart Media memory cards. Continued…
News Article | March 25, 2011
Seattle private equity firm Evergreen Pacific Partners is using some of its financial muscle to merge Radiant Imaging and Zemax Development Corp., makers of testing and measurement tools for LED devices. As a result of the deal — terms of which are not being announced — the company has named Paul Caragher CEO. He most recently was president of Tektronix Service Solutions. Zemax’s software is used by optical engineers for lens design, illumination, laser beam propagation, stray light, fiber optics and other optical technology applications. Radiant’s technology is used for LED display correction and defect detection. The companies technologies are used on both small and large LED screens. (For example, they did the testing on the Qwest Field scoreboard in Seattle). “We will be able to grow faster and go farther together,” said Ron Rykowski, who founded Radiant in 1992 and will remain with the merged company. “With access to capital from Evergreen and economies of scale, we can develop integrated solutions that deliver increased value to customers and generate new revenue opportunities for the company.” Zemax founder Ken Moore added: “This merger will allow us to transform into a global optics design, test and measurement leader with the infrastructure and capacity to serve our customers where they are – which is increasingly in Asia.” The newly-merged company will operate from a facility in Redmond, and for now both companies will maintain their existing brands. Evergreen Pacific Partners manages $700 million. Most of its investments have been made in areas outside of technology, including Gene Juarez Salons & Spas, Haney Truck Line, Nickel Plate Express and Nuprecon. John Cook is co-founder of GeekWire. Follow on Twitter: @geekwirenews.
News Article | July 20, 2006
For over a year now, our review of the 24-inch has been one of the most popular reviews on our site. It has had amazing staying power, keeping in the top 20 articles month after month—quite unusual for a site like ExtremeTech, which favors the hot issue of the moment. Suffice it to say, lots of computer enthusiasts have been watching the ever-dropping price of that monitor and considering a purchase. Sure, we’d all love to have a but that beauty costs over $2,000. We also recently reviewed around the 20-inch mark: The BenQ FP202W, NEC MultiSync 20WMGX2, and Dell UltraSharp 2007WFP. Those who have LCD lust for a large widescreen monitor but still want to keep their costs well under $1,000 are now eyeballing Dell’s UltraSharp 2407WFP, a refresh and update of the previous 2405 model. Is it a worthy successor to the now-classic 2405FPW? Continued…
News Article | July 20, 2006
We test PC monitors using a rigorous combination of lab measurements, synthetic software benchmarks, and subjective viewing of game and DVD content. Game testing primarily involves looking at content with dark scenes and fast motion, while movie viewing focuses on dark-level detail and color fidelity. We also put the displays on the test bench in our using a Minolta CA-210 colorimeter and a Radiant Imaging PM-1400 FAST analyzer. The CA-210 captures color temperature, contrast ratio, and CIE color tracking data, while the PM-1400 allows us to determine the overall bright and dark uniformity of the display. Our lab PC uses an ATI Radeon X1800 XL, with test images either generated by ColorVision’s ColorFacts Professional 6.0 or DisplayMate. We also use a synthetic test developed for PC Magazine that moves a small box around the screen at high speed, allowing us to easily see ghosting, which can show up in high-speed moving content. We perform subjective testing with a variety of PC games and DVD movies. In this case, we used several scenes in Batman Begins, Lord of the Rings: Return of the King, and Finding Nemo, checking for detail and color accuracy. We played a bit of World of Warcraft, F.E.A.R., Oblivion, and Counter Strike: Source to get a feel for how the panel responds in games. We even hooked up an Xbox 360 to the panel’s component input, set the unit to 1080i output, and tooled around in a few games. Continued…