Projector recalibration of three-dimensional profilometry system.

In three-dimensional profilometry, the primary disadvantage of the monocular system equipped with a projector and a camera is that it is often highly dependent on the projector calibration. The projector calibration errors of the principal point and focal length are analyzed in this paper, and result in measuring the object deviation, including not only the rigid transformation, but also the scale transformation. Unfortunately, the deviation cannot be revealed by reprojection, the normal error analysis method. Here, a systematic recalibration method is proposed to correct the projector calibration errors of the principal point and focal length, where an accurate binocular three-dimensional measurement system is applied. The experimental results show that the method is effective. The three-dimensional measurement accuracy of the monocular system is improved approximately from 1.0 mm before projector recalibration to 0.10 mm afterward.

[Three-Dimensional Facial Wrinkle Measurement and Quantification].

The three-dimensional facial wrinkle measurement and quantification have important applications in many fields, which are implemented by an entire system proposed in this paper. The system uses stereo vision method based on structured-light to achieve three-dimensional facial wrinkle measuring, where the system calibration, corresponding points matching and three-dimensional reverse method are implemented. Furthermore, the facial wrinkle is considered as the noise attached on smooth facial profi le so that the facial wrinkle is acquired quantitatively by three-dimensional noise acquisition and morphologic processing method. The experimental results show that this system can accomplish accurate facial wrinkle acquisition and objective quantifi cation. This system has comprehensive applications as it is non-contact and it has high precision.

A Transparent Vessel-on-a-Chip Device for Hemodynamic Analysis and Early Diagnosis of Intracranial Aneurysms by CFD and PC-MRI.

Hemodynamics plays a critical role in early diagnosis and investigating the growth mechanism of intracranial aneurysms (IAs), which usually induce hemorrhagic stroke, serious neurological diseases, and even death. We developed a transparent blood vessel-on-a-chip (VOC) device for magnetic resonance imaging (MRI) to provide characteristic flow fields of early IAs as the reference for early diagnosis. This VOC device takes advantage of the transparent property to clearly exhibit the internal structure and identify the needless air bubbles in the biomimetic fluid experiment, which significantly affects the MRI image quality. Furthermore, the device was miniaturized and easily assembled with arbitrary direction using a 3D-printed scaffold in a radiofrequency coil. Computational fluid dynamics (CFD) simulations of the flow field were greatly consistent with those data from MRI. Both internal flow and wall shear stress (WSS) exhibited very low levels during the IA growth, thus leading to the growth and rupture of IAs. PC-MRI images can also provide a reasonable basis for the early diagnosis of IAs. Therefore, we believed that this proposed VOC-based MR imaging technique has great potential for early diagnostic of intracranial aneurysms.