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We have developed a projector which can display high-resolution images of Super Hi-Vision (7680 x 4320pixels) and has a high dynamic range of 1.1 million to 1. This projector features a serial combination of two modulation blocks: the first for chrominance and the second for luminance. While a conventional projector has one modulation block that contains three devices to modulate red, green, and blue light, our projector has another modulation block that contains a device for luminance to further modulate the combined RGB modulated light. We measured some characteristics of the projector, which are modulation transfer function, dynamic range, and tone reproduction. We found that the projector can resolve Super Hi-Vision images and that it has an extremely high dynamic range and a fine 12-bit tone reproduction. We did two types of subjective evaluations with the projector to research the effect of the resolution of the chrominance component and that of the limited dynamic range of the display on the total image quality. The results of the first evaluation indicate viewers do not notice the image degradation when the resolution of the chrominance component is degraded to a half of that of the luminance component. The results of the second evaluation indicate the dynamic range of at least 1000:1 is necessary for displaying natural images and the dynamic range of about 30000:1 is necessary for displaying special images which have low average picture levels.

An extremely high-resolution image system called the Ultra High Definition TV (UHDTV) system, with more than 4000 scanning lines is being developed by the Japan Broadcasting Corp. (NHK). This system provides audio and video with an acute sense of reality so that viewers feel as if they are actually at the site of the filming. UHDTV cameras, projectors, disk recorders, and three-dimensional sound systems have already been developed. UHDTV programs were demonstrated at the 2005 World Exposition, Aichi, Japan, and the system worked successfully there during the six-month run. This paper presents two aspects of the newly developed UHDTV transmission systems: an optical transmission system with dense wavelength division multiplexing (DWDM) technology for contribution, and a codec system based on MPEG-2 for program distribution. A live transmission of uncompressed material with a 260-km single-mode fiber was also performed. For program distribution, some experiments were conducted at bit rates of 200 to 640 Mbits/sec via experimental satellite transponders or IP networks. These transmission experiments demonstrate the feasibility of using UHDTV in future broadcasting.

We have developed an extremely high-resolution display (Super Hi-Vision display) system that has quadruple the amount of the horizontal and vertical resolution of HDTV. The extremely high-resolution display consists of two LCD projectors, for green and another for red and blue, so convergence errors between green and red/blue images exist on the screen. We introduce a method for automatically adjusting the convergence that detects convergence errors by displaying mountain-like patterns using a digital-camera. The projector for green images has a resolution equivalent to 7680×4320 pixels with a spatial pixel-offset method using two 3840×2160 LCD panels. In this case, two green panels must be located at an exact spatial offset of 0.5 pixel. We developed a method for detecting a misalignment of spatial offset by using two sine-wave patterns with different phases.

HDTV is flourishing in Japan and the U.S., and many other countries including those in Europe are planning to start their own services. Europe is now designing the route map to deploying HDTV. The recent progress in related technologies has accelerated the spread of HDTV throughout the world. In particular, the prospects for the picture format of 1080/50p, 60p are growing. This paper will try to give further insights on the prospects of HDTV. First, it will discuss the visual experience that HDTV gives the viewers in relation to his/her viewing environment. Then it will examine the trends toward 1080/50p, 60p from various perspectives, including flat panel displays, production equipment, coding technologies, HDTV television sets, higher resolution technologies beyond HD, and the trends of rival media.

We studied the synergism of resolution and gray-scale levels in image recognition in relation to the precise phase detection in vernier acuity. Humans who have a 1.0 visual acuity candetect 1.0 minute-size (1/60 degree) objects. Video systems are designed based on this data. On the other hand, it has been reported that human can detect an approximately 2.0-second (2/60/60 degree) phase shifts. We found that precise position detection is possible with a low resolution detector if the number of gray-scale levels is sufficient. We applied this principle to the position adjustment on a multi-screen display system.

A system format that optimizes viewer appreciation of Ultrahigh-definition and Wide-screen (UDW) images was investigated ; in particular, the relationships among the screen size, viewing distance (angle), screen aspect ratio, and the number of pixels. A linear relationship was found between the screen size and preferred viewing distance. Comparison of the preference for images with four aspect ratios and with 16:9 aspect ratio showed that the preferred aspect ratio depends on the screen size, not the viewing angle, with about 2:1 most preferred in the home environment. The relationship between the screen size and aspect ratio was thus given by a simple equation. An equation for relating the maximum number of pixels necessary for a UDW system to three parameters (screen size viewing distance, and aspect ratio) was derived using the visual resolution capacity.

Modulation transfer function (MTF) quantitatively describes a display' s resolution characteristics. It involves two measurement methods : the impulse method and the sinusoidal method. The authors compared the two methods and showed that the sinusoidal method is the best of the two because the video circuit characteristics are involved in the results. The MTF measurement method for moving images is also investigated.

This paper describes an investigation results of optimum screen size and viewing distance (angle) for viewing ultra high-definition and wide-screen television (UDW), and the psychological effects of UDW images. First, it is found that a shorter relative viewing distance is preferable to that of the HDTV system and that the preferred viewing distance for UDW images depends not on relative figures using the image height, but instead screen size. Second, it is found that the preferred viewing angles coincide with the positions where the maximum combined effects of “potency” and “comfortableness” are obtained, and that, compared with the HDTV system, UDW images, when viewed at the preferred viewing angles, can give much higher level of emotional feeling with regard to both “potency” and “comfortableness”.

The effectiveness of using a PLUGE (picture line-up generating equipment) signal to improve a display's grayscale reproduction under ambient illumination was investigated using two new metrics. Experimental results showed that adjusting a display's brightness with a PLUGE signal enables more precise adjustment than with a general image. A metric for the volume of reproducible color space was used to describe the area that a display can reproduce in the color space. A metric for the color reproduction reduction rate was used to describe how gray-scale reproduction deteriorates under ambient illumination. The values obtained for these metrics showed that adjusting the brightness with a PLUGE signal improves grayscale reproduction.

We have produced digital pictures to be used in subjective assessments of HDTV picture quality.A drum scanner is used as the input device, to assure useful quality for the assessments, and a series of signal processes are performed by computer. Some technical factors, such as resolution, aliasing, color reproduction, gray scale characteristics and precision of quantization are taken into account in producing the digital pictures.To reduce the alias component, 16-times over-sampling is employed and sub-sampling with filtering is performed by computer. Gray scale characteristics are corrected by polynomial approximation, and color reproduction is compensated for by linear matrixing. After signal processing, precision of quantization becomes equivalent to that of the 10-bit linear quantization applied to the gamma pre-corrected video signal.

A 50-inch diagonal rear-projection display for HDTV has been developed. The resolution on the screen is more than 1000 TV lines, and the contrast ratio is improved by the optical coupling between the CRTs and the projection lenses. The display contains two mirrors in order to make the depth of the display smaller. One of the mirrors contains three photodiodes in order to allow the detection of the convergence error that occurs on the screen. Examining the outputs of the photodiodes, a CPU, located within the display, can detect and correct the convergence error.

Because Hi-Vision signals are ultimately viewed on a display, it is no overstatement to say that the image quality of these signals depends on the display.

— An experimental projector that features double modulation to obtain high-resolution (4096 × 2160 pixels) and high-dynamic-range images has been developed. Although a conventional projector contains three modulators for red, green, and blue and outputs light after combining the modulated light from these three sources, our projector has an additional modulator for luminance that modulates the combined RGB modulated light. It can display high-resolution color images by combining three low-resolution panels for chrominance modulation and one high-resolution panel for luminance modulation. In addition, the dynamic range is dramatically improved because the double-modulation scheme minimizes black levels in projected images. The projector demonstrates an extremely high dynamic range of 1.1 million to 1 and 10-bit tone reproduction.

— For future broadcasting, NHK is studying new video services offering very-high-picture quality achieved through Super Hi-Vision. Toward that aim, a projection display that has a resolution equivalent to 7680 × 4320 pixels by using four 4096 × 2160 D-ILA™ panels has been developed. The display requires precise convergence adjustment because it consists of two projection units, so an automatic adjustment system was developed. Although the pixel number of the digital camera used is less than that of the display, a 0.2-pixel accuracy was obtained. This report introduces theaters that use this display as an example of applying the Super Hi-Vision video system.

— An ultrahigh-definition display system quadrupling the horizontal and vertical resolution of HDTV has been developed. In order to obtain the ultrahigh definition, four LCD panels (red, green 1, green 2, and blue) are combined using the spatial pixel-offset method. Therefore, only green images have an ultrahigh resolution of 4096 × 7680 pixels, while red and blue images have 2048 × 3840 pixels. The ultrahigh resolution was confirmed by subjective assessment testing. The scores of the test have the same tendencies as the SQRI values. The necessary accuracy of the convergence correction is calculated to be within 0.3 pixels by the modified s-CIELAB method.

— The s-CIELAB is a powerful tool in evaluating color reproduction errors in images. However, the formula is not yet completed, and a few refinements to the formula will enhance the accuracy of this tool. From a simple simulation, a black-and-white pattern causes unexpected false color components when using the s-CIELAB formula. We show how these false color components are obtained with this formula. The main reason is a combination of components from different lowpass filters (LPFs). We show a method that improves this situation by introducing new psychological values and propose a modification to the formula employed by s-CIELAB. The new formula is compatible with the psychological values L*u*v*, and a simulation with general images shows that the new method does not cause any false color components.