The possibility of real-time subtitling of news programs-using an uncondensed transcription of the words spoken by the newsreader-was considered for people with impaired hearing. Before the system can be created, the effectiveness and preferred format of subtitling need to be investigated. In order to evaluate the comprehensibility of real-time subtitling, subjects with impaired hearing were shown a short news program with subtitles and without sound, and their comprehension of its contents was subsequently tested. Results indicated that the subjects performed about as well after viewing a program with subtitles at the full rate of 280-350 Japanese characters per minute as people with normal hearing did after viewing a program with sound only, and better than after viewing a program with neither subtitles nor sound. Furthermore, they showed no less comprehension than when the subtitles are condensed to 50-70%, as is common broadcasting practice, suggesting that real-time subtitling at full rate is effective for people with impaired hearing.

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We have been studying methods of transmitting electronic-character information into braille to facilitate access for visually or both sight and hearing impaired persons. In this study, we devised new braille-transmission methods and experimented to evaluate the intelligibility of passive reception on a limited number of display devices. The 6-digit/character method, which distribute 6 points of braille to 6 corresponding fingers and stimulates each fingertip, produced a 90 percent or higher rate of recognition for the presented braille characters. On the basis of the evaluation result, a new method for presenting sequence of braille data was devised and teletext broadcasting braille-transmission equipment was developed.

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With the increasing number of on-board visual displays, it is important to develop displays that are easy to see in various driving environments, such as a snow-covered road. In this paper, we propose a new displaying method that is based on luminance adaptation, one of the human vision properties which is associated with luminance changes that occur while driving. In this method, the level of adaptation by the driver is estimated to the luminance outside the vehicle. Then the luminance and the chromatic saturation of the display is determined by using the adaptation luminance in order to perceive the constant brightness of the display in different environmental luminances. Experimental results of subjective and objective evaluation that compare the conventional display and our new one indicate the effectiveness of the method.

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This paper proposes a method for using a color simulator to extracted colorimetric factors related to the feeling of depth produced by painted automobile panels. Our color simulator can generate photorealistic graphic color panels and control the appearance with Munsell color parameters. As a result, several important factors related to human depth sensitivity have been precisely and efficiently extracted, and applied to the design of the new paint colors that give more of a feeling of depth than present colors.

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This paper looks at the basic properties of impressions which pictures give and estimates the impressions. The method used to estimate the impressions, synthesizes each impression separately. Each impression is obtained from the elements of a picture. To examine the validity of this method, impressions of a color image and a contour image which are produced from an original picture are measured separately by using the SD method. An impression of an original picture is predicted from impressions of the color and contour image. The results of this experiment show that the impressions of an original picture related to color (i.e. vividness and brightness) are expressed by two impressions from a color image and a contour image.

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In this paper, we examine the construction factors of color Kansei information which are perceived from single colors. To examine the construction factors, we perform a subjective evaluation experiment based on the Semantic Differential method which uses 201 monochromatic colors and 12 adjective pairs. Three factors were detected by using the factor analysis. This paper also investigates the ability of the potential interpolation method to estimate factor scores of arbitrary color stimulus. We carried out the potential interpolation for several uniform color spaces. The performance of the interpolation of the CIE L*a*b* was good. Finally, the average of the estimation error was within the individual dispersion of the subjective experiment.

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An area of uneven brightness is a typical defect which influences the screen quality of a LCD display. At present in LCD manufacturing lines, inspection of such uneven areas depends on sensitive visual judgements by skillful inspectors. To automate the inspection process, an inspection system is required which can determine the degree of defect of uneven areas using a visual recognition system with a discriminatory capability similar to human sight. An evaluation of the relation between the characteristics of uneven areas and their visual conspicuity degree is also needed. This paper describes experiments to evaluate the characteristics of uneven areas that influence human visual perceptibility. The experimental results show that contrast, location, diameter, aspect ratio, width and length influenced visual perceptibility.

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The frame frequency used in TV and movies, as well as that used in VDT's, is higher than the critical fusion frequency (CFF). But, because the CFF is determined for a static scene, flicker is perceived when there is a moving object in the dynamic scene. In this research we investigated the fundamental characteristics of flicker perceived in the dynamic scene. The stimulus was a moving edge in the flickering visual field by Maxwlian view, and the flicker frequency exceeded the CFF. The threshold frequency of flicker perception at the moving edge, which rose with the edge velocity from about 6 deg/s, then saturated at about 90 Hz when the edge velocity was about 20 deg/s and then rose again. The result suggests that the mechanisms of flicker perception depends on the velocity of the moving stimulus.

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It is known that the ability to use peripheral vision changes when a central visual task exists. This suggests that the focus-of-attention in the central visual field causes a reduction in performance in the peripheral visual field. We studied how the load of attention in the central visual field when the eye moves would change sensitivity to chromatic and luminance contrast in the peripheral visual field. Our results showed that the load in the central visual field impaired sensitivity to chromatic and luminance contrast in the peripheral visual field, under the conditions with and without eye movements. This suggests that, even when the eye moves, the state of attention is the primary factor attending changes in the distribution of visual sensitivities across the visual field.

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To evaluate the effects of visual attention (VA) on human involuntary miniature eye movements (MEM), we analyzed the microsaccades (MSC), which are components of MEM, under the following three experimental conditions : 1) VA was focused on the foveal object, 2) VA was dispersed in the parafoveal visual field, and 3) VA was focused on one of the parafoveal objects. The results showed that the VA was not focused on the foveal object, the frequency and amplitude of the MSC increased, and the scatter of fixation widened. The results from 2) and 3) showed that the frequency of the MSC was grater in 2) and the mean amplitude of the MSC was similar for both conditions. When VA is not focused, the MSC occur more frequently, and when VA is focused on the foveal object, the amplitude of the MSC reduces. These results suggest that MEM are influenced by VA, and MSC may be used as an indicator of the attentional state. It will be possible to establish whether VA is focused or not on the basis of the analysis of MEM characteristics.

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This paper analyzes changes in the timing of a spontaneous blink by altering the time of a figure offset at different several points during a figure identification task, which is based on a time-varying image presentation technique. To compare with the conventional discrete trial task, additional task is also designed. In this task, a still image which is presented at immediately before a figure offset in the former task is presented to a subject in a brief exposure duration. We found that concentrated blinks occurring after a figure offset in either of the tasks is concerned with the factor of stimulus offset. Although there is a relation between blink latency and the task difficulty, we cannot conclude that a blink tends to occur just after the termination of the identification processing.

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Three new objective performance evaluation criteria, C/Vn (Carrier to Visual noise ratio), N/Vn (Noise to Visual noise ratio), and C/N (Carrier to Noise ratio), for imaging systems are proposed. These criteria are quantified based on visual noise characteristics derived from a human vision model formulated by the author in an output image from imaging systems, to which a sine-wave is inputted, C/Vn and N/Vn are defined, respectively, as the quantity of the perceptible sine-wave component with the frequency equal to the input sine-wave and as the quantity of all the perceptible noise components, and C/N is a simplified expression for integrating C/Vn and N/Vn. These criteria are applied to the performance evaluation of imaging systems based on the density-gradation-method such as CRTs, LCDs, printers and so on. They are calculated as parameters of pixel aperture ratio, quantizing level number, and pixel size. In actual computation, pulse-amplitude-modulated sinusoidal waves are used as output images from such imaging systems. The calculated fundamental characteristics suggest that the objective performance evaluation criteria are effective in quantitatively expressing human subjective evaluation judgments.

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The induction field model can be used to explain some experimental psychological results of a pattern recognition process for letters. A lot of research has been carried out to explain the recognition process and the features of letters. However, there is no mathematical model that can explain the results of psychological experiments for letters. Recently, dynamics has been focused on as the concept that explains the recognition process. Furthermore, the induction field model based on dynamics can explain some psychological experimental results for some artificial patterns. This paper verifies that this model can explain some psychological experimental results for letters.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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A silhouette backprojection method is proposed. The acquired occluding hull is especially useful for describing natural scenes and modeling. Theoretically the hull is obtained as the intersecting regions of sweeped silhouettes backprojected from many viewpoints. Because making such intersecting regions is a binary operation, a lot of fuzzy information along the occluding contours is lost during the process. To improve precision, we devised a continuous-tone silhouette backprojection method which allows us to use more sophisticated grayscale image processing such as smoothing and edge enhancement. Experiments show that this method retains weak object details which are sometimes lost by using the traditional binary operation.

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[in Japanese]

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