In this paper, we propose the new method to track the human head by using the location and color information. Some previous methods, which use multiple cameras, are performed inside two dimensional images. But, we expand it to the tracking in three dimensional voxel space. The voxel space is reconstructed by integrating the depth maps obtained from the multiple stereo cameras. It is necessary to integrate information efficiently to track in real time. Particle filter, which has the robustness for noise, is used to track the human head. The integrated voxel region should be restricted to the minimum necessary for particle filter. Thereby we can obtain images, integrate information and estimate the position of the human head in real time.

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In this paper, we propose the new method to track the human head by using the location and color information. Some previous methods, which use multiple cameras, are performed inside two dimensional images. But, we expand it to the tracking in three dimensional voxel space. The voxel space is reconstructed by integrating the depth maps obtained from the multiple stereo cameras. It is necessary to integrate information efficiently to track in real time. Particle filter, which has the robustness for noise, is used to track the human head. The integrated voxel region should be restricted to the minimum necessary for particle filter. Thereby we can obtain images, integrate information and estimate the position of the human head in real time.

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Mixing time measurement has been carried out to understand the agitation of a water bath contained in an inclined cylindrical vessel subjected to bottom gas injection. Particular attention has been paid on the effect of swirl motion on the mixing time. The mixing time increases with an increase in the inclination angle. Accordingly, the vessel inclination is not effective for bath agitation. In addition, the effect of tracer charge method on the mixing time has been investigated.

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The impact stress waves produced when a human being runs, leaps or jumps, are propagated from the foot bone to the femur and hip bone through the tibia and fibula. In this paper, we report the experimental studies on the behavior of propagation of impact stress waves in the femur and hip bone when the impact is applied to the shitsumin of an acupuncture point, or tsubo-spot, located in the sole of a foot. We analyze the behavior of the stress wave propagation in the model of femur and hip bone by means of the high speed photoelastic analysis method with the aid of a semiconductor strain gauge, and examine the existence of acupuncture point and meridian in the femur and hip bone from mechanical point of view. From our experimental results on the high speed photoelastic observation and strain-time relation, we have been able to conjecture that the meridian, or keiraku, in oriental medicine connecting the ichuu of an acupuncture point with the zakotsukon of an acupuncture point exists above the femur bone.

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This paper describes the feasibility of using finite element analysis to predict stress distributions in mandibular bone treated with a distal-extension partial denture, compared with conventional photoelastic method. A finite element model was constructed based on the CT scan data of the three-dimensional photoelastic model, which was anatomically realistic replica of a patient mandibular bone with teeth. A vertical loading was applied to a specially designed metal pyramid mounted on the first molar region to mimic functional movements of the partial denture. The numerical results showed that higher stress was observed in the apical and distal sides of the abutment teeth, which was the similar tendency to the experimental results obtained by the photoelastic method. Moreover, stress distributions depended on the variety of loadings applied to the different point of the pyramid. The present analysis may give a better prediction of stress distributions in patient mandibular bone than the photoelastic method.

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This paper describes an instantaneous phase-stepping method for interferometry and two-dimensional photoelasticity. The camera that has a pixelated form-birefringent micro-retarder array acquires phase-stepped fringes in a single camera frame. Then, Stokes parameters that represent the state of polarization are calculated from a single image. In the case of the polarization interferometer, the phase difference of the two orthogonally polarized light beams can be easily determined from the Stokes parameters. On the other hand, the phase distributions of the isochromatics and the isoclinics are obtained in the case of the photoelasticity. It is emphasized that this method is applicable to the study of the mechanics of time-dependent materials because multiple exposures are unnecessary for sufficient data acquisition in the completion of data analysis.

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The aluminum alloy A2024-T3 was overaged at 573 K for different aging times, and then subjected to the hardness measurement and the fatigue testing. The hardness decreased successively with increasing aging time, but the fatigue life largely decreased to a half of the initial life after aging for 2 h or longer. The ultrasonic measurement was carried out with overaged specimens to examine changes in ultrasonic parameters with the aging time. The peak intensity (PI) gradually decreased with increasing aging time, but the average gradient of the transfer function (AGTF) largely decreased and became almost constant after aging for 2 h or longer. The ultrasonic measurement was also carried out in-process during the fatigue testing by using the water bag. The ultrasonic parameters (PI and AGTF) increased with the number of fatigue cycles (N) with considerable scatter, and the average rate of AGTF in the fatigue process (d(AGTF)/dN) increased with the aging time up to 4 h.

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The goal of this paper is to present a three-step color phase shifting approach for automatic determination of the whole-field isoclinic parameter based on the results of photoelastic experiment. A plane polariscope is used with a white light. Relevant theories of the intensity equations and the optimum phase shift angle are derived. The optimum phase shift angle is numerically determined. The obtained wrapped phase data is unwrapped to the true phase interval by the unwrapping process. The obtained results show not only the method allows the isoclinic parameter to be evaluated with almost free from the influence of the isochromatics but also the isoclinic map coincides with theory.

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Acetabular prosthesis loosening is associated with structural characteristics of the implant-bone system and the operative procedure. In order to improve the service life of the cup, it is important to develop the material, design, fixation mechanism, etc. and to assess the mechanical behavior around the cup. In this study, stress condition around the artificial acetabular cup before and after the worn is investigated by three-dimensional finite element method. The FEM model was constructed on the basis of the CT image around the cup and profile measurements of the cup worn in vivo for approximately 15 years. The results obtained are as follows. (1) In the cup before the worn, the load transmitted from femoral head to cup is mainly distributed within the cup, and the influence on bone cement and cancellous bone is small. (2) In the worn cup, the load is not sufficiently distributed within the cup, and as a result, the compression stress is caused locally in the worn area of the cup and the tensile stress in the circumference increases. (3) The tensile stress inclination increases in the boundary of bone cement and cancellous bone, when the thickness of bone cement is small.

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A mercury target for spallation neutron source is subject to pressure waves caused by proton bombarding mercury. The pressure wave propagation induces the cavitation in mercury that imposes pitting damage on the target vessel. In this paper, single micro-bubble behavior in mercury was evaluated using numerical calculation on the basis of bubble dynamics. Impact pressure loading tests using an electro-Magnetic IMpact Testing Machine were performed to measure the impact pressure and acoustic vibration. Additionally, in order to visualize micro-bubble behavior in mercury, high-speed video camera observation was carried out. As the result, we confirmed that the maximum bubble radius and lifetime of micro-bubble are dependent on the imposed pressure and the pressure saturate time and that the acoustic vibration with high frequency components above 15 kHz is exited by the micro-bubble collapse.

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A model investigation has been carried out on argon bubble attachment to the sliding gate settled in the immersion nozzle of continuous casting process. Water and air are used as the model fluids for molten steel and argon gas, respectively. A downward air-water two-phase flow is generated in the immersion nozzle. The wettability of the sliding gate is changed by coating fluororesin on it. Bubbles attach preferably to the poorly wetted sliding gate. The velocity of water flow is measured with particle image velocimetry (PIV). Bubble attachment patterns can be classified into eight categories. An empirical equation is proposed for the critical condition describing the bubble attachment. The flow in the immersion nozzle is affected strongly by bubble attachment to the sliding gate.

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