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Tetsuo Mitsuhashi

Bio: Tetsuo Mitsuhashi is an academic researcher. The author has contributed to research in topics: Stereoscopy & Image quality. The author has an hindex of 1, co-authored 1 publications receiving 18 citations.

Papers
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Proceedings ArticleDOI
01 May 1994
TL;DR: In this article, the subjective image position was measured for geometric figures and actual scenes while varying the resolution, contrast, brightness, and color between the L- and R-pictures.
Abstract: In stereoscopic picture systems, the image should be reproduced in a psychologically proper position that allows comfortable stereoscopic perception. Position matching in observer space between the stereoscopic image and a small marker was successfully adopted to measure the subjective image position. The subjective image position was measured for geometric figures and actual scenes while varying the resolution, contrast, brightness, and color between the L- and R-pictures. The image moves closer to the screen in proportion to the increase in resolution difference. A pair of color and darker monochrome pictures can reproduce acceptable stereoscopic images without conspicuous color rivalry. Mental fatigue is also an important factor in comfortable stereoscopic image viewing. The CFF is discussed together with other factors such as accommodation characteristics, picture quality, and viewing conditions that relate to future stereoscopic TV systems that allow comfortable viewing.

18 citations


Cited by
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Proceedings ArticleDOI
TL;DR: A novel method for calculating stereoscopic camera parameters is described, which provides the user intuitive controls related to easily measured physical values and precisely controlled perceived depth, and a new analysis of the distortions introduced by different camera parameters was undertaken.
Abstract: Stereoscopic images are hard to get right, and comfortable images are often only produced after repeated trial and error. The main difficulty is controlling the stereoscopic camera parameters so that the viewer does not experience eye strain or double images from excessive perceived depth. Additionally, for head tracked displays, the perceived objects can distort as the viewer moves to look around the displayed scene. We describe a novel method for calculating stereoscopic camera parameters with the following contributions: (1) Provides the user intuitive controls related to easily measured physical values. (2) For head tracked displays; necessarily ensures that there is no depth distortion as the viewer moves. (3) Clearly separates the image capture camera/scene space from the image viewing viewer/display space. (4) Provides a transformation between these two spaces allowing precise control of the mapping of scene depth to perceived display depth. The new method is implemented as an API extension for use with OpenGL, a plug-in for 3D Studio Max and a control system for a stereoscopic digital camera. The result is stereoscopic images generated correctly at the first attempt, with precisely controlled perceived depth. A new analysis of the distortions introduced by different camera parameters was undertaken.

250 citations

Journal ArticleDOI
TL;DR: The results showed that the subjective quality of a stereo image sequence fell approximately midway between the quality of the left- and right-eye views, consistent with known properties of binocular vision, in particular with the averaging of brightness and contrast of stimuli presented to the two eyes.
Abstract: The present research assessed the subjective image-quality of stereo sequences where the left- and right-eye views differed in severity of compression. Viewers watched image sequences where the left-eye view was displayed at a higher quality than the right-eye view, and rated the combined overall subjective image-quality of the sequence. Three stereo image sequences were used for assessment. Each sequence, in the ITU-R 601 format, was 10 s in duration and the images for the left-eye view were coded independently of the right-eye view, at bit-rates of 6, 3, 2 and 1 Mbits/s, using MPEG-2, Main Profile/Main Level syntax. These were combined to generate stereo sequences where the bit-rates were (left : right) 6 : 6, 6 : 3, 6 : 2, 6 : 1, 3 : 3, 3 : 2 and 3 : 1. The resulting stereo sequences were viewed by 26 subjects, and rated in terms of subjective image-quality. The rating methodology was based on the double-stimulus continuous-quality scale method described in ITU-R Recommendation 500. The results showed that the subjective quality of a stereo image sequence fell approximately midway between the quality of the left- and right-eye views. The results are consistent with known properties of binocular vision, in particular with the averaging of brightness and contrast of stimuli presented to the two eyes.

95 citations

Proceedings ArticleDOI
13 Nov 1994
TL;DR: The psychophysical property of the human visual system, that only one high resolution image in a stereo image pair is sufficient for satisfactory depth perception, has been used to further reduce the bit rates in this paper.
Abstract: Stereoscopic sequence compression typically involves the exploitation of the spatial redundancy between the left and right streams to achieve higher compressions than are possible with the independent compression of the two streams. In this paper the psychophysical property of the human visual system, that only one high resolution image in a stereo image pair is sufficient for satisfactory depth perception, has been used to further reduce the bit rates. Thus, one of the streams is independently coded along the lines of the MPEG standards, while the other stream is estimated at a lower resolution from this stream. A multiresolution framework has been adopted to facilitate such an estimation of motion and disparity vectors at different resolutions. Experimental results on typical sequences indicate that the additional stream can be compressed to about one-fifth of a highly compressed independently coded stream, without any significant loss in depth perception or perceived image quality. >

35 citations

Journal ArticleDOI
TL;DR: The algorithm effectively combines the simplicity and adaptability of the existing block based stereo image compression techniques with an edge/contour based object extraction technique to determine appropriate compression strategy for various areas of the right image.
Abstract: We propose a hybrid scheme to implement an object driven, block based algorithm to achieve low bit-rate compression of stereo image pairs. The algorithm effectively combines the simplicity and adaptability of the existing block based stereo image compression techniques with an edge/contour based object extraction technique to determine appropriate compression strategy for various areas of the right image. Unlike the existing object-based coding such as MPEG-4 developed in the video compression community, the proposed scheme does not require any additional shape coding. Instead, the arbitrary shape is reconstructed by the matching object inside the left frame, which has been encoded by standard JPEG algorithm and hence made available at the decoding end for those shapes in right frames. Yet the shape reconstruction for right objects incurs no distortion due to the unique correlation between left and right frames inside stereo image pairs and the nature of the proposed hybrid scheme. Extensive experiments carried out support that significant improvements of up to 20% in compression ratios are achieved by the proposed algorithm in comparison with the existing block-based technique, while the reconstructed image quality is maintained at a competitive level in terms of both PSNR values and visual inspections.

29 citations

Journal ArticleDOI
TL;DR: CFF is an effective measure for objectively measuring the fatigue of television observers, including observers of binocular stereoscopic television, and is found that with respect to CFF viewing of around 30 min was allowable.
Abstract: The method of binocular stereoscopic imaging has attracted attention as a simple and technically feasible means of three-dimensional (3-D) display. It has been said, however, that the binocular picture system is more fatiguing to view than a conventional two-dimensional picture, such as the current television picture. The main objective of this paper is to evaluate quantitatively fatigue caused by binocular stereoscopic picture viewing, to clarify the basic characteristics of this type of picture. Various measurement methods of fatigue have been proposed, and that using the critical flicker frequency (CFF) has found wide use in measurement of mental fatigue and is easy to make. Actual measurement in this study used the CFF value obtained in a descending series of the method of limits, normalized to the value at the start of measurement for each observer, and the CFFs of all observers then averaged. It was found that the measurements produced stable and highly accurate results. CFFs of the observers of a c...

28 citations