Computer-generated hologram (CGH) is a hologram generated by simulating recording process in optical holography. High resolution output devices are required to observe 3D images. However, resolution of output devices is not high enough to display interference pattern. Therefore, viewing zone and visual eld are limited. To improve these problems, this paper proposes a method for enlargement visual eld by enlarging reconstruction area in CGH using the Fourier transform optical system. Optical reconstruction experiments were carried out, and results of these experiments showed that the proposed method enlarge visual eld and reconstruction area.
A computer-generated hologram (CGH) is a technology expected to achieve ideal 3D displays. To achieve realistic 3D displays using a CGH, it is necessary to establish rendering technologies. However, studies about them are not sucient. Especially, an established method for expressing refraction that arises when a light passes through a transparent object is not available. We describe a new calculation method considering refraction. This method is based on a ray-tracing method used to express optical phenomena such as refraction in computer graphics. We made holograms by this method and conducted optical reconstruction experiments. The results of these experiments showed that the proposed method is valid to display objects with refraction.
"Tour Into the Picture (TIP)" is one of Image-based rendering method for actualizing walk-through from a single image. This paper proposes a method of constructing three dimensional space from a single landscape image using TIP. A problem of TIP is to be incapable with large movement of viewpoint because foreground objects are at plates. To solve the problem of TIP, the proposed method generates solid models of foreground objects, and constructs three dimensional space with the models and a background image. An experiment was carried out, and the result shows that reasonable three dimensional space is constructed from a landscape image.
In this paper, a method of creating contents data for a new spatial 3D display which can draw dots of light to represent an object in space is proposed. The Aerial 3D display that we use in this research can create a dot of light at 50 kHz, and can display it in an arbitrary position by vector scanning. Since it can display a higher density of dots of light, we expect that the desktop system can represent more complex objects, such as 3D surface models consisting of polygonal patches, which are generally used in computer graphics. The proposed method represents the surface with cross sections of an object against the vertical direction and generates a point sequence data for vector scanning. From the experiments of drawing, it can be seen that polygonal models can successfully be drawn by the proposed method.
Recently, in the field of computer graphics, researches for simulating realistic motion of fluids based on computational fluid dynamics have been studied by many researchers. In addition to these researches, several methods to generate desired shapes by controlling the fluid simulation have also been developed. However, the fluid motion controlled by the previous methods often looks unnatural since unrealistic external forces are used to control the fluid simulation. In this paper, we focus on the simulation of water and propose a method that is able to control the motion of water to naturally form a shape specified by the user by optimizing parameters of simulation.
Recently, 3D films and 3D TV sets are releasing and we can watch 3D images in daily life. However, the stereoscopic method used by these 3D systems are not suited for human perceptual for three dimensional objects. A Holo TV system based on a holographic technique is an ideal 3D communicate system, unfortunately, it has never been realized for a commercial base because it has technical difficulties. In many laboratories around the world, researchers study Holo TV systems, and these researches have been greatly advanced during this decade. This paper introduces the present of researches and the difficulties for the realization, at the last discuss problems needed to solve and the future of the 3D Holo TV.
One of the main subjects of tone reproduction is to produce the pictures optimized to display, transferred from real world's luminance via camera. In our study, we propose a new tone reproduction method for TV program production, especially for high-contrast outdoor live programs. Our method performs contrast improvement for specified luminance range without influence over another range. We verified our method by prototyping realtime system on graphics workstation, and also we measured the performance of HDTV video processing.
Smoking has various influences on the living body.That is,there are an appearance of disease of the lung cancer and a hematogenous disorder due to the vasoconstrictor. The purpose of this research examind the temperature change by smoking,and measured the temperature of the hand palm by using thermogram.The temperature change of the time series of the palma manus was requested by processing of the subtraction between the measurement data.The palma manus temperature was admitted to decrease by smoking.The temperature change in the palma manus area was able to be observed by the subtraction image.
Applications with projector(s) and camera(s) will be more popular since both devices became inexpensive. We proposed a touch-screen system combined with a projector and a camera. Our system recognizes a hand and its shadow in a projected button area, and determines whether the user is touching the button by calculating the ratio of the hand and its shadow area. It’s essential to accurately recognize their areas on the video images from the camera input. In this paper, we propose a method to accurately separate the hand area and its shadow to pick up their pixel values in the system initialization. According to the color distribution of hand and its shadow in the initialization, likelihood of hand and shadow for the pixels in the button area are determined. By using the ratio of the amount of shadow likelihood and hand likelihood of those pixels, we can achieve stable touch detection and button drag.
In this paper, practical application plan of the video and animation application to a vocational training course is described. According to our previous study, video or animation content should be applied to general introduction phase or practical operation scene with dynamic motion. A trial to apply the result to existing training course has been planned. Analysis and modeling of the course by means of UML has been tried, and the application strategy of the video and/or animation content to the course has been described.
In the subband image coding, the optimum band partition method is to minimize the quantization noise power in the encoded image when the coding rate is given. However, the previous method has the problem of the computational costs to determine the optimum band partition in the 2-dimensional frequency domain. In order to solve the problem, the new algorithm for the optimum band partition is proposed by giving the attention to the kurtosis of the subband signals. As the results, our algorithm can improve the computational costs about 1/75 than the previous method.
In this paper, we present a lossy image coding method based on a variable density sampling. In a DCT based coding scheme such as JPEG, large deterioration may be caused in the high frequency domain of the encoded image at low bit rate, because bit assignments for high frequencies are rather few. In our proposed method, the back ground region of the image is down-sampled by reducing the sampling rate and the object region which has much high frequency components is up-sampled by linear interpolation. Thus the number of pixels of the back ground region is reduced and the frequency of the object region can be dropped to lower one. Consequently the degradation of the image quality in the object region can be suppressed.
Adding noise in flat region of an image is noticeable for human eye. On the other, slightly changing pixel values in edge region is less noticeable. This characteristic is applicable to embed data in an image. In this study, we propose a method to embed the watermark data in the edge region of an image by using the discriminant analysis method. The discriminant analysis method is the method of image binarization. In the proposed method, an image is divided into blocks of fixed size at first. Secondly, pixels in each block are classified into two classes using the discriminant analysis method. At the final step, watermark information is embedded by changing the between-class variance under the pre-defined rule. A simulation experiment is performed to evaluate the quality of the embedded image and to verify effectiveness of the proposed method.
Visual cryptography is a technology that hides a secret image in other images and the hidden image can be decoded by the human visual system. A conventional method based on error diffusion method can product two high quality binary halftone images from two gray-scale images and we can decoded a gray-scale secret image by superposing these halftone images. In this paper, we consider about intensity transform to generate binary halftone image for high-quality decoding of a secret image in the conventional method. We added histogram equalization to conventional method and evaluated quality of images. As a result, we could decode the secret image more high-quality than conventional method.
This paper proposes a decreasing technique of increase rate of data size in the partial scrambling technique. In the proposed technique, quantized DCT coefficients in I-frames are shuffled or changed by a target image quality for PSNR. The amount of change to scramble is corrected in order to be independent on the kinds of videos, and to shuffle or to change the quantized DCT coefficients is selected to decrease the increase rate of data size. In addition, the result of increase rate of data size and subjective evaluation experiment show the effectiveness of the proposed technique.