This paper proposes a method for designing a coded aperture, which is installed in a projector for active depth measurement. The aperture design is achieved by genetic algorithm. In this paper, a system for depth measurement using projector and camera system is introduced. The system involves a prototype projector with a coded aperture which is used to reconstruct a shape using Depth from Defocus (DfD) technique. Then, we propose a method to create a coded aperture to achieve the best performance on depth measurement. We also propose an efficient calibration technique on defocus parameters and a cost function for DfD to improve the accuracy and the robustness. Experimental results show that the proposed method can create an aperture pattern using simulation considering noise for fitness calculation. Evaluations are conducted to confirm that the proposed pattern is better than other patterns with our depth measurement algorithm.

In this paper, we propose an active 3D measurement method using structured light system, which can measure wide range of depth. General structured light system requires correspondence between projection patterns and camera observed patterns. Hence, both the projected pattern and the camera image should be in focus on the target. This condition makes a severe limitation on depth range of 3D measurement. Our technique resolves the range limitation by using coded aperture (CA) on projector. It can be understood as a structured light system using Depth from Defocus (DfD) technique, in which defocus of projected light pattern is utilized. By allowing blurry pattern of projection, the measurement range is extended compared to common structured light system. Moreover, CA efficiently improves its accuracy.

In this paper, an easy calibration method for projector is proposed. The calibration handled in this paper is projective relation between 3D space and 2D pattern, and is not correction of trapezoid distortion in projected pattern. In projector-camera systems, especially for 3D measurement, such calibration is the basis of process. The projection from projector can be modeled as inverse projection of the pinhole camera, which is generally considered as perspective projection. In the existing systems, some special objects or devices are often used to calibrate projector, so that 3D-2D projection map can be measured for typical camera calibration methods. The proposed method utilizes projective geometry between camera and projector, so that it requires only pre-calibrated camera and a plane. It is easy to practice, easy to calculate, and reasonably accurate.

This paper describes a method for robustly detecting and efficiently recognizing daily human behavior in the real world. The proposed method involves real-world sensorization using ultrasonic tags to robustly observe behavior, real-world virtualization to create a virtual environment by modeling real objects using a stereovision system, and virtual sensorization of virtualized objects in order to quickly register the handling of objects in the real world and efficiently recognizing specific human behavior. A behavior-to-speech system created based on this recognition method is also presented as a new application of this technology.

We have achieved a test technology for mixed signal ATE suitable for use in a production test environment for the characterization of the loop response and VCO sensitivity of PLL's having response times of a few microseconds. This is a task that was previously not possible on mixed-signal ATE as it requires a Time Measurement Unit (TMU) utilizing a digital interpolator capable of making high speed "consecutive, instantaneous frequency measurements".>

The authors describe a high-frequency clock source using jitter reduction circuitry to minimize the effect of problems in test and measurement systems. A mathematical explanation of the errors imposed by jitter is presented, along with a discussion of the hardware used to minimize its effects. Test results that demonstrate the benefit of the jitter minimization technique are provided. A reduction in the jitter of a clock signal from 100 ps peak to peak to 10 ps peak to peak has been realized by using this technique. This results in a direct improvement in AC measurement accuracy when low jitter clocks are used as conversion start signals.>