The optimal HDTV viewing distance is the distance that provides the observer with an optimal, immersive visual HDTV experience. Although opinions vary on the right screen size for distance relationships, formal research and recommendations suggest more closely is preferred to go further, to provide a more profound experience. How close? "As close as you can bear".
Video Optimum HDTV viewing distance
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HDTV is designed to provide a more realistic experience than a television system designed to be replaced. The "thrilling realism" HDTV effort on offer arises from an increase in resolution (detail) and a typically large screen size. The larger view improves the visual angle in which the content is viewed, both of which contribute to the enhancement of feelings of presence. Thus, the correct visibility is essential to enjoy HDTV as intended. While helping to determine the HDTV standard, RCA engineers (and then vice president) Bernard J. Lechner performed a preliminary analysis to see the distance under various conditions, lowering what is called the Lechner distance.
Existence
The concept of presence has been described as the sensation of "reality", "being there", and as a "illusion of non-mediation". The concept of attendance is derived and studied in relation to Virtual Reality (VR) and other 3D environments. It was then established that television viewers could also sense presence. Attendance is influenced by a number of factors, including video camera techniques, audio allegiance, visual and aural dimensions, and most relevant to this topic, image size (visual angle) and quality (angular resolution).
Visual angle
Optimal optimal viewing is affected by the camera's horizontal angle that captures the image. One optimum optimal viewpoint concept places viewers where the horizontal angle sublimated by the screen equals the horizontal angle captured by the camera. If this is the case, the angular relationship felt by the viewer will be identical to that recorded by the camera.
If the camera angle is always the same, optimal viewing distance can be easily calculated. However the camera's horizontal angle varies as the lens's focal length changes. If the camera's sensor has a fixed dimension, the shorter focal length (short-angle) lens captures a wider viewing angle, which requires viewers to sit closer to the screen. Conversely, longer-focal length (telephoto) lenses capture a narrower viewing angle, demanding a further viewer position.
Such opposite viewpoints are not only impractical, but will negate the purpose of telephoto shooting (for example, to see objects that are much more detailed, or minimize distortion in the face image) and wide angle shots (causing viewers to sit too close to the screen, where artifacts unwanted images will be visible).
One compromise assumes the lens is "standard" (focal length 50mm, for standard 35mm format). The "standard" lens maintains the same spatial relationships felt by the audience at the camera location. For "standard" lens images, visibility should be the same as the diagonal length of the screen.
It has been shown that seeing a view that occupies a larger visual angle (also referred to as the field of view) increases feelings of presence. More importantly, the wider the visual angle (approximately 80 degrees flat), the greater the sense of presence.
Angle resolution
With printed graphics, resolution refers to the number of pixels (commonly referred to as "dots") in a fixed linear measurement. With HDTV, the resolution is measured by the number of pixels in physical view. As the resolution of the printed image increases, the image is cleaner, sharper and more detailed. However, image quality is not not increases if the resolution increase exceeds the viewer's visual capabilities. For HDTV images to look better, the resolution per arc degree (or angular resolution) should increase as well as the number of screen pixels.
Maps Optimum HDTV viewing distance
Recommendations
To maximize feelings of presence and thus provide a better viewing experience, viewers need to be placed in the theoretical places where HDTV occupies the widest viewing angle for that audience. It is also important that the screen resolution per degree of arc remains at a high quality level. Opinions about where the position of nirvana is many and varied.
Recommendations on HDTV visibility are divided into two general classes; fixed distance based on HDTV display size, or range of distances by display size. The most common recommendations from a fairly authoritative source are presented below.
Fixed spacing
Long distance recommendations are more common than two types. For the most part, many of the recommendations issued by a fixed distance before the end of 2007, when HDTV display is still in the early adoption stage. Recommended distance remains the most frequently cited are listed.
diagonal measurement ÃÆ'â € "2.5 (according to the viewing angle of 20 degrees)
One of the more popular recommendations on the right HDTV viewing is doubling the diagonal measurement of the display screen by 2.5. This recommendation is cited by respected television manufacturers, retailers, publications and websites, although the popular CNET electronic review website shows that high-resolution content can be watched at a shorter distance - 1.5 times the diagonal measurement of the display screen (according to viewpoint 32 level ).
Diagonal measurement ÃÆ'â € "1.6 (corresponding to a 30 degree angle)
Viewing HDTV from a position where the screen occupies a 30-degree field of view is widely cited as a recommendation of SMPTE (or SMPTE 30) (equivalent to about 1.6264 times the screen size in a 16: 9 TV). This recommendation is very popular with the home theater fan community, appearing in books on home theater design, and also supported by white paper produced by Fujitsu. Although an article on research sets the specifications for the next HDTV evolution, Ultra HDTV (or UHDTV), supports the premise that HDTV is optimized for 30-degree viewing, it seems that there is no direct recommendation from SMPTE on the issue.
Diagonal measurement ÃÆ'â € "1.2 (corresponding to a 40-degree angle)
THX recommends that "the best seat-to-screen distance" is where the viewing angle is approximately 40 degrees, (the actual angle is 40.04 degrees). Their recommendations were originally presented at CES 2006, and were expressed as theoretical maximum horizontal viewpoints, based on the average human vision. In THX's opinion, the location where the view is viewed at a 40-degree viewpoint provides the ultimate "immersive cinematic experience", all the same. For consumer applications from their recommendations, THX recommends dividing the diagonal screen measurements by 0.84 to calculate optimal viewing distance, for 1080p resolution. This is equivalent to multiplying the diagonal measurement of about 1.2.
Optimal range
Express the optimum visibility as a range rather than as a fixed distance increases; probably because of a typical HDTV buyer profile change. Early adopters of HDTV are usually videophiles, technical adventurers and sports fans who want to get the best viewing experience. At present, typical HDTV consumer targets may be a bit simpler; total immersion took the back seat to the room integration. Large retail chains such as Best Buy that once declared their recommendation as a fixed distance, started providing range recommendations. Manufacturers have also started to provide coverage recommendations, updating their websites with small applications that show optimal viewing distance as distance. THX in March 2009, added various recommendations to their website. The minimum end of the range tends to be a recommendation of fixed proponent optimum distance.
Manufacturer's recommendations
The recommendation ranges from producers are the simplest of the groupings. For the minimum (or nearest) visibility, they recommend a viewing angle of about 31 degrees; and for maximum, viewing angles as low as 10 degrees. The 10-degree viewing angle is approximately the angle normally seen by NTSC television
Retail recommendations
Current recommendations posted on Best Buy and Crutchfield reseller sites take more middle ground. Both retailers post a minimum visibility that accommodates a point of view just slightly above the average 32 degrees. This viewport approaches the angle of view required to be able to see pixel level details. Maximum visibility will provide a viewing angle of about 16 degrees with Best Buy recommendations and about 20 degrees with Crutchfield's. The maximum visibility (minimum viewing angle) provided by Best Buy aligns with theoretical vision at the highest spatial frequency visible to the human visual system. Crutchfield's maximum visibility is parallel to the lower limit where viewers usually begin to discover immersive HDTVs.
Rentang THX
While THX still believes that the optimal viewing distance is the position where the screen occupies a 40-degree viewing angle for the viewer, they also provide range recommendations. The minimum visibility is set to estimate a 40-degree viewing angle, and the maximum visibility is set to an estimated 28 degrees.
High screen
Consideration should also be given to the height at which the screen is placed. The general suggestion is that the viewer's eyes are horizontally aligned with the bottom or center of the screen, so the screen does not outperform the viewer. THX recommends that the heads of viewers should not look for more than 15 degrees.
Factors that affect calculations
Each recommendation serves the underlying purpose of the organization that proposes it. Manufacturers will have an easier time selling their HDTVs if they support positions that do not require consumers to buy as many sets as required by THX recommendations. In the absence of economic influence, calculating the best screen size for the distance ratio that will result in a complete feeling of presence is not entirely easy. There are a number of factors that may affect calculations including the limitations of the human visual system, the technological limitations of HDTV displays, human physiological considerations, the content to be viewed, and the interpretation of empirical data from formal testing. There is also the fact that the screen image is on a flat and not curved plane. Perhaps the biggest of these is the uncertainty that surrounds the boundaries of the human visual system, and how those limits apply to what we see and feel. Further consideration, more practical, is one room size, including the position of speakers, seating and other furniture in the room.
Limitations of the human visual system
The human visual system has a fixed capacity to detect detail from a distance. Our understanding of limits relating to the recognition and identification of visual details from a distance is based primarily on the work of Dr. Hermann Snellen. Dr. Snellen developed an eye examination chart that bears his name (Snellen chart). From his findings and the work of others over the past hundred years, the first minute is seen as a threshold beyond which important details can not be identified, by someone with normal vision. An arcminute is an angular measurement, equal to 1/60 of a degree of circle. Normal vision is referred to as 20/20 or 6/6 vision in North America and Europe respectively. The visual acuity threshold has been identified as a constraint factor in recommendations on optimal viewing distance for HDTV, and also in formal studies that comment on television problems and angular resolution. Assuming a flat screen, with 1 arcminute as an obstacle to seeing important details, in order not to miss any detail, viewers need to be placed in a position where their viewing angle to 1080p HDTVs is approximately 31.2 degrees or larger (32 degrees for rounded view ), for 2160p HDTV about 58.37 degrees or bigger (64 degrees for ball view) and 4320p HDTV about 96.33 degrees or bigger (128 degrees for ball view). However, there is not always an agreement that the Snellenian limit should be an inhibiting factor.
To calculate the visibility, based on the size of the display and content resolution, the following formulas can be used:
Sitting outside this distance will result in loss of detail.
A 1998 Sun Microsystem paper on the boundaries of human vision and video display systems uses different constraint values ​​of approximately ½ minute arcs (or 30 arcseconds), when estimating saturation points for the human visual system. With a 30-second arc as a constraint, the viewing angle required to see all the detail provided by HDTV with 1080p resolution drops to about 16.1 degrees. In addition, some academic articles have challenged the idea that 1 minute resolution is the typical solving power of the human eye, indicating that on average, we can complete a smaller detail than that. Also, there is the problem of vernier sharpness, which is the ability of the eye to detect offsets between 2 lines and stereoacuity, which is the ability to distinguish depth with the use of both eyes. Vernier sharpness and stereoacuity are cited as detectable with only second-degree separation of 2-4 arcs. Ultimately all of the different kinds of sharpness play a role in how we see things and more importantly, how we see what we see. The complexity of the human visual system and the relationship between different types of sharpness have not been fully understood. Thus, depending on the limits of the human vision system applied, the calculation of the viewpoint will vary to some extent, especially when technological constraints are taken into account.
Technology limitations
When viewing HDTV screens from a shorter distance can result in an increased sense of presence, technological limitations can have an adverse effect if the viewers are too close to the screen. If you check the LCD screen or plasma HDTV when turned off, you can see the pixel lattice construction. Enabling the display does not completely cover this. If you get too close to the screen when it's on, it can look as if you saw it through the screen door. Even with different HDTV display technologies, such as front or back DLP projections, LCoS or laser TV, the way HDTV images are rendered limits how close audiences can be before the image segmented nature becomes clear.
Displays HDTVs produce images in the same way computer bitmaps (also known as raster graphs) are produced, using 4-sided colored mosaic pixels. Like a computer monitor, each HDTV display has a video resolution consisting of rows and columns with a certain number of pixels. From a considerable distance, the human eye sees the illuminated pixels as smooth images. As one gets closer, a point occurs where the yellow appearance of individual pixels becomes real. The image then loses its subtlety, its quality decreases, and the benefit of looking closer becomes a loss.
Calculates the point at which the human eye can detect indirect pixels. Obviously, the visual acuity of people varies greatly. But the pixel geometry also varies, in form and distance (known as the interpixel gap), depending on the technology and screen design.
Human physiological considerations
Research conducted on attendance with HDTV and other higher resolution formats that use a wide field view, has revealed that sometimes feelings of presence can be too real, producing physiological effects that some viewers may not want. Subjects have reported increased symptoms common to motion sickness when seeing strong visual stimuli on large screens. A study conducted using virtual reality simulations as part of the experiment, found that subjects with lower visual vision experienced more symptoms associated with motion sickness. In addition, the study also found that the symptoms of motion sickness increased when subjects observed visual stimuli without the help of their glasses or contact lenses. As a result, optimal visibility recommendations based solely on human visual systems and technological limitations do not always result in the best viewing experience. Viewers with lower visual acuity, who prefer to watch HDTV without their corrective lens may want to sit closer to see important details and run the risk of unwanted side effects.
Selection of end-user content
Although studies show that the presence and size of images are directly correlated, calculating the size to see distance relationships may not be a necessary exercise for all consumers. A 1997 study, hypothesized that an increase in screen size would increase feelings of presence, finding that content was more important than screen size. The finding is that for commercial, action-adventure and reality programming, increased feelings of presence are not correlated with increasing size. Researchers attribute these findings to the fact that the above-mentioned content contains scenes taken from the viewpoint of the camera, scenes with abrupt movements and shorter photo shoots. Conversely, for programming consisting of talk shows and drama programs changing screen size has no effect on feelings of presence.
See also
- Contrast sensitivity
- Viewing Angle
- Large screen television technology
- HDTV
- Home Theater
- Sweet spot (acoustic)
References
Source of the article : Wikipedia
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