Originally Posted by jrp
This is Jim from Lumagen. As the architect of the Lumagen Radiance NoRing(TM) scaling algorithm I would like to try to clarify some things about scaling technology.
First, the Radiance 2041 and 2042 scaling was not originally our NoRing scaling, but it is now. So any comparison should be done with the latest software release.
Next I would like to comment on the Darbee. We place the Darbee at the source resolution - where it should be. All our tests, and those of others we have talked to, shows that it is significantly better to have the Darbee at the source resolution. Darbee can enhance the perceived sharpness of an image when used in moderation. I find that a setting much above HD-mode 30 creates too many artifacts, but I like the effect Dabree has with a setting in the HD-25 to HD-30 range. My final comment on Darbee is I would like to point out that the Darbee has nothing to do with a discussion on scaling, but of course is a feature that is worth noting in a product.
Now on to scaling technology: The Radiance scaling does NOT try to artificially sharpen the image. The design goal was for very low pass-band-ripple and a flat frequency response that approaches the Niquist sampling frequency as close as is rational. All other scalers (that we know of) create "ringing" as they scale. The Radiance NoRing does not create ringing. Ringing is best seen as a "halo" around objects in real video (which I find objectionable) or it can be seen in test patterns as lines around large steps in the test pattern.
The problem is that ringing, while an error and an objectionable artifact (e.g. Halo effect), can make an image appear sharper. So in my opinion the key is to evaluate the overall image accuracy, and not just look at the artificial edges created by the ringing. We are not opposed to comparisons, and I believe, as has been the case the comparisons of the past few years, that when all aspects of image quality are weighed, that the elimination of the scaler ringing is a much better trade off for overall image quality than the artificial sharpening created by the ringing or peaking of the image in other scalers.
The Oppo uses the Ancor Bay (aka DVDO) scaler in the Silicon Image chip. Historically whenever groups have done an evaluation of the Ancor Bay scaling verses the Lumagen NoRing scaling, the Lumagen scaling has won as providing the best overall image quality. Note, I am not saying that other scalers are bad. I am saying that when all aspects of image quality are considered the Radiance scaling is judged superior.
If sharpness is what you crave, you can use the Radiance edge enhancement feature to sharpen the image. The edge enhancement when used in moderation can sharpen the image while not adding too much ringing. And of course in the Radiance 20XX series the Darbee is available and supports saved setting for each input, input resolution and each of four input memories, and will provide optimal results since it is placed at the source resolution portion of the pipeline.
Some people like Darbee at HD-80. I may not be able to convince those people that accuracy is the key to sclaing since they are ignoring all the artifacts created by Darbee with a setting of 80. If you like Darbee at 80, or the sharpness created by ringing in your scaler, I absolutely agree that everyone gets to choose what they like to watch. It's just that I don't like the artifacts created by these, and I believe most people would agree with me.
Finally, scaling is just one aspect of the Radiance. The Radiance allows a system to be correctly calibrated, and allows for many other custom setup adjustments - such as anamorphic screens (both 2D and 3D) without the use of an anamorphic lens, plus a host of other setup features.