Showing papers by "Chia-Hsiang Menq published in 2017"
TL;DR: Real-time image processing algorithms and associated mathematical formulas that render ultraprecise three-axis visual motion tracking and the ability of the proposed approach to eliminate measurement bias is validated are validated.
Abstract: Real-time image processing algorithms and associated mathematical formulas that render ultraprecise three-axis visual motion tracking are presented. The principle of three-axis motion tracking is based on lateral sampled white light interferometry (LSWLI) and real-time unbiased image registration. Two distinct regions of interest (ROIs), i.e., in-plane ROI and out-of-plane ROI, in a single 2-D image, taken at a single time instant, are processed in real time. Real-time continuous image registration (CIR) is realized and applied to 2-D shadow projection image content of the object to locate the object’s in-plane position, whereas adaptive 1-D CIR (A1-CIR) is proposed and applied to an LSWLI fringe pattern on the object to determine its out-of-plane position. Processing of images is synchronized with real-time image acquisition to realize three-axis motion tracking. Computer simulations are used to demonstrate bias caused by image registration and to examine its effect on measurement precision. The ability of the proposed approach to eliminate measurement bias is validated. Experimental results are presented and used to examine measurement resolution for positioning and to illustrate measurement precision for long-range motion tracking.
3 citations
TL;DR: MicroSPECT/CT image acquisition and analysis for thyroidal RAI uptake is greatly improved by the cradle and the CTViewer software, respectively, and the approach of superimposing thyroid VOIs from t24 images to select thyroidVOIs on corresponding aligned t1 images can be applied to studies in which the target tissue has differential radiotracer retention from surrounding tissues.
Abstract: Background: The ability of thyroid follicular cells to take up iodine enables the use of radioactive iodine (RAI) for imaging and targeted killing of RAI-avid thyroid cancer following thyroidectomy. To facilitate identifying novel strategies to improve 131I therapeutic efficacy for patients with RAI refractory disease, it is desired to optimize image acquisition and analysis for preclinical mouse models of thyroid cancer. Methods: A customized mouse cradle was designed and used for microSPECT/CT image acquisition at 1 hour (t1) and 24 hours (t24) post injection of 123I, which mainly reflect RAI influx/efflux equilibrium and RAI retention in the thyroid, respectively. FVB/N mice with normal thyroid glands and TgBRAFV600E mice with thyroid tumors were imaged. In-house CTViewer software was developed to streamline image analysis with new capabilities, along with display of 3D voxel-based 123I gamma photon intensity in MATLAB. Results: The customized mouse cradle facilitates consistent tissue configuration am...
2 citations
TL;DR: An automated calibration system in conjunction with a3-D quadratic model is presented to render rapid and accurate calibration of the laser measurement system to extend the 3-D position detection volume of BFP interferometry.
Abstract: Back focal plane (BFP) interferometry is frequently used to detect the motion of a single laser trapped bead in a photonic force microscope (PFM) system. Whereas this method enables high-speed and high-resolution position measurement, its measurement range is limited by nonlinearity coupled with crosstalk in three-dimensional (3-D) measurement, and validation of its measurement accuracy is not trivial. This Letter presents an automated calibration system in conjunction with a 3-D quadratic model to render rapid and accurate calibration of the laser measurement system. An actively controlled three-axis laser steering system and a high-speed vision-based 3-D particle tracking system are integrated to the PFM system to enable rapid calibration. The 3-D quadratic model is utilized to correct for nonlinearity and crosstalk and, thus, extend the 3-D position detection volume of BFP interferometry. We experimentally demonstrated a 12-fold increase in detection volume when applying the method to track the motion of a 2.0 μm laser trapped polystyrene bead.