<p>We present a measurement method for obtaining three-dimensional (3-D) images of the thoracic and abdominal body surface during respiration. This method generates a color pattern composed of R, G, and B cosine stripe patterns to obtain a single image-based 3-D measurement. The 3-D wavelet transform is adopted to extract wrapped phases from a stripe image sequence to improve the accuracy of the wrapped phase extraction. Then, a two-frequency temporal phase unwrapping formula is proposed and extended to a multifrequency formula according to the geometric relationship between the wrapped and the unwrapped phase curves, which enhances its anti-interference performance and calculation speed. Simulations and body measurements reveal that the proposed method can effectively measure the 3-D body surface during respiration. By using multiple characteristic parameters, this method overcomes the limitation of only using feature points to represent respiratory movement on the thoracic and abdominal body surface. This method has important applications for tracking respiratory motion during clinical radiotherapy.</p>
In this paper, structured light three-dimensional measurement technology was used to reconstruct the porcelain shape, and further more the porcelain color was reconstructed. So the accurate reconstruction of the shape and color of porcelain was realized. Our shape measurement installation drawing is given. Because the porcelain surface is color complex and highly reflective, the binary Gray code encoding is used to reduce the influence of the porcelain surface. The color camera was employed to obtain the color of the porcelain surface. Then, the comprehensive reconstruction of the shape and color was realized in Java3D runtime environment. In the reconstruction process, the space point by point coloration method is proposed and achieved. Our coloration method ensures the pixel corresponding accuracy in both of shape and color aspects. The porcelain surface shape and color reconstruction experimental results completed by proposed method and our installation, show that: the depth range is 860 ∼ 980mm, the relative error of the shape measurement is less than 0.1%, the reconstructed color of the porcelain surface is real, refined and subtle, and has the same visual effect as the measured surface.
In this paper, a passive ultrasonic method for 3-D position is introduced, based on TDOA (Time Difference of Arrival). In the method, the distances between the ultrasonic source and receivers are calculated through measuring the differences between of the arrival times when the ultrasonic from the measured target reaches the ultrasonic receivers in different location, and the 3-D position is realized. Our method avoids the disadvantages of the current approaches: exactly recoding times of the ultrasonic emission and receipt, and the synchronization timing of the emitter and receiver. In this method, the 3-D position can be realized as long as the target has the ultrasonic source that can be accepted by the receivers. Thus, this method could achieve 3-D position of the non-cooperative targets, which can be applied in broader fields, especially in military. This paper not only established the mathematical model of the method and analyzed its design keys, but also came up with the design example as well as its simulation. Both of the theoretical analysis and experimental results show that position range is 50m(<i>x</i>)×50m(<i>y</i>)×50m(<i>z</i>) and position accuracy is 0.1m(<i>x</i>)×0.1m(<i>y</i>)×0.3m(<i>z</i>). So the method and apparatus are feasible and effective.