Philips’ Aurea Flat TV includes its Ambilight Spectra TV backlighting and the Perfect Pixel HD Engine.
Philips (officially Royal Philips Electronics) is the only remaining independent European consumer electronics maker. The company has three divisions: consumer electronics/small appliances, lighting, and medical equipment.
Philips has been working on TV technology since the beginning of TV, and was the first to use optical storage for video, resulting in the LaserDisc and eventually the audio CD. Philips’ current TVs are well-known for the Ambilight backlighting feature, and the company has always been an innovator in picture-quality improvement techniques. So when Philips publishes a Technology Backgrounder on its 2008 Perfect Pixel HD engine, one has an excellent opportunity to catch up with the latest tricks in picture enhancement.
What Consumers See on TV
Philips’ consumer research indicates that sharpness is what consumers are first able to assess and recognize in terms of TV picture quality. The second quality indicator is motion performance. So the first (2007) version of Perfect Pixel picture improvement focused on these two aspects. The 2008 version brought further improvements in contrast and color.
The first problem with sharpness is moving objects. A film camera records at 24 images per second, while the TV operates at 50 or 60 Hz. To get to 100/120 Hz, you just repeat each frame, or even repeat some frames more than once. This works well with fast CRT scanning (the old glass picture-tube TVs), but LCDs are slower and produce judder: objects move unevenly and are not sharp.
Many modern motion improvement techniques take two video frames, analyze the content, and use sophisticated algorithms to generate new frames that are inserted between them, thus creating natural movement of sharp objects on the display. Processing power of the TV can be comparable to, and often exceed, the fastest gaming PCs, as is indicated by the capability of performing 500 million pixel computations per second. All frame rates (25/30p, 24p, 50/60i and 50/60p) can be processed, all at 1080 lines.
The next aspect addressed is contrast, and here Philips uses a process called Luminance Transient Improvement (LTI). The way a color transitions into the neighboring color is improved. If an image includes white next to blue, there will typically be a transient area of light blue pixels. LTI makes this light blue area smaller; the color separation becomes stronger, and objects appear sharper.
Another process is Line Thinning: the image of a line, such as from a spider web, is made thinner but the contrast is enhanced.
While it may be wonderful to generate additional frames to achieve higher frame rates, a slow display response time can still result in a blurred image. Philips uses improved control techniques and Overdrive Control, which essentially increases the voltage to accelerate the LCD reaction.
To Philips, adding frames, keeping them sharp, and reducing LCD response time are all key to an optimized picture. Progress is fast: last year Philips offered a 3-millisecond response time with 250 million pixels processed per second; this year response is down to 2 milliseconds and the number of processed pixels has doubled.
Quadrillions of Colors
The 17-bit Color Booster has a palette of a staggering 2250 trillion colors, and focuses on pixels with low saturation. It is programmed to avoid oversaturating skin colors as well as white-tone shifts.
Gray levels are also important. A new 10-bit panel driver supports 1024 gray levels instead of 256 (8-bit). Big color planes in the picture (such as the sky) have smoother contours.
Contrast is always a problem for LCD. The CCFL backlight limits the contrast, and Philips introduced backlight with Intelligent Dimming, resulting in darker areas without hiding details. Still, plasma is considered largely superior in this aspect.
Next, the picture processing performs gamma correction: positive correction makes more details visible in dark areas, where negative correction does the same for lighter areas.
Viewing angle is another weak point for LCD, and Philips claims its Perfect Contrast is better than the competition when viewed at a 60-degree angle. This means better contrast, unchanged color variation, and no gamma shift (interference of colors and brightness/saturation).
To reduce side effects of video compression (which are worsened during resolution enhancement), the input signal is improved in the input stage, called PerfectÂ Clean. The most flat and the most detailed areas are analyzed, and a balance is chosen between artifact reduction and sharpness.
Europe has been slow in adapting HDTV. The UK is leading, partly because they have always been, and because many UK users have satellite TV, which is easier to upgrade to HD. In Germany and France cable is widespread, and cable operators have been slower. Many Europeans still use analog cable.
But now the European soccer tournament, the Tour de France, and the Olympics all are available in HD, and they’re expected to boost sales. Remember also that large TV’s—bigger than 46 in.—are rare in Europe. A 32-in. TV fits nicely into small European houses and condominiums, but many Europeans feel that, with a TV of that size, you don’t really need HDTV.