Home » Best HDTV shopping guide: color and definition

Best HDTV shopping guide: color and definition

  • by

HDTV Color

In the past, when we walked into the HDTV stores and saw the TV selling walls, we could clearly feel the color differences of different brands of HdTV: some bright, some gray, some unreal. There are three main reasons for this difference: gamut, color management and color accuracy.

Gamut refers to the range of colors that can be expressed by a certain device. The visible light in nature constitutes the largest gamut space in the world, including all colors that can be seen by human eyes. However, due to the development of display technology, our common mobile phones, TVs and other devices can not display all colors completely. In order to directly represent the gamut range, CIE International Lighting Association has developed “CIE XY chromaticity diagram”, which is the figure below.

In this figure, the colors that can be displayed by various devices and fields are represented by triangles. The larger the area of triangles, the more colors that can be displayed or displayed by devices, such as scenes of flowers. Our common gamut standards include rec.709, NTSC, P3, etc. the relationship between these gamuts is roughly as follows:

Internationally, NTSC products with 92% color coverage are generally called wide color gamut. In order to meet this standard, major manufacturers also show their own skills. One of the most popular technologies is quantum dot technology, which can achieve an amazing 110% NTSC TV gamut.

In addition to the wide gamut of hardware, color management and color accuracy are two important factors for good-looking colors. We often see that kind of color is very gorgeous, people’s skin is red, very fake products in TV stores. This is a typical TV with poor color management.

When it comes to color management, we have to emphasize Sony. Color management is a very complex process, in addition to advanced algorithms, the most important is a complete contrast database. The ups and downs of Sony in the field of television and film for decades have accumulated a huge and advanced database. This database is the “dual image database” in Sony TV (the role of this database will be mentioned later). This “wide gamut + color management algorithm + image database” constitutes Sony’s unique “Terri charm color” technology.

Color accuracy also has a great influence on the appearance of TV pictures. As the name suggests, color accuracy is the accuracy of TV color display, but it is basically impossible to restore the color of the object itself. Therefore, the industry has developed a series of standards to specify the accuracy of color, of which the most important indicator is delta E.

How to calculate △ e is very complicated, but for our ordinary users, it is enough to remember the following sentence: the higher the △ e is, the larger the color deviation is; the lower the △ e is, the more accurate the color is. When purchasing, we can refer to this standard:

6-3.2 human eyes can hardly distinguish the difference of color;

The trained people can distinguish the difference of color.

HDTV definition

In principle, after the hardware quality of HDTV has reached the standard, watching movies is a very comfortable thing. But the problem is that the quality of most of our shows on the market is very poor. Generally speaking, the files of a 4K Blu ray movie are about dozens of gigabytes. However, the size of movie and TV series resources on major Internet platforms is only 1-2g. Not to mention live TV, except for the extremely rare 4K pilot stations, most HD stations have only 1080p resolution, and local stations have only 720p and 480p resolution.

The degradation of image quality is mainly reflected in the reduction of resolution, color fault and noise. Therefore, TV manufacturers also optimize these three aspects, and the “image quality processing chip” plays a key role here.

The image quality processing chip firstly reduces the noise of the TV picture to remove the noise, mosaic and other contents in the low image quality film source. Then compared with the internal database, the super segmentation algorithm is used to improve the resolution of the film source and eliminate the color scale, so as to improve the clarity of the picture.

The last step to improve the definition of HDTV picture is the MEMC motion compensation technology. Most of the HDTV programs in China are made in PAL format, with frame rate of 25 frames per second. For ordinary programs, 25 frames is enough. But for football, car racing, action movies and other high-speed sports scenes, the picture will appear drag shadow. After turning on the MEMC motion compensation, it can greatly slow down this phenomenon and make the picture clearer and smoother.

Leave a Reply

Your email address will not be published. Required fields are marked *