Of course, 3D playback in 3D Tvs is very popular among many consumers and greatly affects the choice of TV. Unfortunately, many companies reduce this direction due to a number of reasons. But, today the market still offers a wide range of these models.
Today, 3D playback uses anaglyph, active shutter and passive polarization technologies.
3D anaglyph technology
This technology was the first and most popular, but today it gives way to more perfect technologies. In this technology, 3D effect is achieved by encoding image separately for each eye with the help of color filters. Typically, the red filter is used for left eye and the blue filter is used for right eye. Therefore, special glasses have color filters in eyepieces. Each filter matches to the color that is used during image encoding.
Image for red channel falls to the red filter of glasses and is absorbed. The eye is not sees it. This image is reproduced only through the eyepiece with a blue filter. The same occurs in the other channel. The encoded image falls to the blue filter and is absorbed. A red filter passes it to the eye. In fact, each eye through a filter glasses gets the opposite color from two identical pictures that are slightly offset from each other. This creates illusion for the human brain and, respectively, 3D effect. Unfortunately, color filters partially absorb the colors and shades of the spectrum in the range next to red and blue, reducing the color gamut of the image.
Active shutter 3D technology
This technology uses alternating playback of video frames for the left and right eyes. Thus, TV screen at one time shows only one image for the left or right eye.
The image for other eye appears in the next time moment. Special glasses alternately perform the function of shutter for each eye. Opening and closing is carried by feeding current on filters in the eyepieces. Battery is located in the glasses.
The high depth of the 3D image is its main advantage. The high cost and weight of glasses due to the battery, eye fatigue due to constant flickering, distance limitations (visible lines disappear at a distance of more than two diagonals) and different viewing angles (178 В° vertically and 90-100 В° horizontally) are the main disadvantages of this technology.
The passive polarization 3D technology
This 3D technology uses different operation principle and does not contain of the power supply in glasses. The formation principle of three-dimensional image is based on the use of linear or circular polarization for light waves. Today IMAX cinemas use this technology.
Formation of three-dimensional image uses two images that are simultaneously displayed on the screen. Each image has its own polarization. The images are skipped at different angles through the light filters and are transmitted to the eyepieces of glasses.
Glasses also have own optical filters. They filter the light flow for each eye. The right eye receives the image through one filter, and the left eye receives the image through another filter. Thus, 3D volumetric image is created with the help of two projectors and eyeglasses with special filters.
The instability of a 3D image when viewed on a small screen is the main drawback of this technology. Rotating the head relative to the screen can destroy the perception of the three-dimensional image. LG Cinema 3D technology does not have this disadvantage. Cinema 3D uses a circular light polarization with opposite direction for each eye.
But, unfortunately, it’s available only in LG TVs.
This video demonstrates the difference between passive and active 3D technology.
