Optical design and evaluation of a 4 mm cost-effective ultra-high-definition arthroscope

Multi-Sensing Inspection System for Thermally Induced Micro-Instability in Metal-Based Selective Laser Melting

Additive manufacturing (AM) excels in engineering intricate shapes, pioneering functional components, and lightweight structures. Nevertheless, components fabricated through AM often manifest elevated residual stresses and a myriad of thermally induced micro-instabilities, including cracking, incomplete fusion, crazing, porosity, spheroidization, and inclusions. In response, this study proposed a sophisticated multi-sensing inspection system specifically tailored for the inspection of thermally induced micro-instabilities at the micro-nano scale. Simulation results substantiate that the modulation transfer function (MTF) values for each field of view in both visible and infrared optical channels surpass the benchmark of 0.3, ensuring imaging fidelity conducive to meticulous examination. Furthermore, the innovative system can discern and accurately capture data pertaining to thermally induced micro-instabilities across visible and infrared spectra, seamlessly integrating this information into a backend image processing system within operational parameters of a 380-450 mm distance and a 20-70 °C temperature range. Notably, the system's design is harmoniously aligned with the requisites of processing and assembly, heralding a significant advancement in bolstering the inspection effect of thermally induced micro-instabilities for the AM component.

Size matters - From the working channel to the wavelength of light: Optimizing visualization in endoscopic spine surgery

BACKGROUND

Minimally invasive surgery bases many of its benefits on decreasing tissue disruption. Endoscopic spine surgery has continued to push the boundaries to accomplish successful clinical outcomes through the evolution of the endoscope and working channel. As the indications for endoscopic spine surgery increase, a more profound discussion of cannula size selection for endoscopic spine surgery is required. The intimate relationship between the working channel, the endoscope and how these choices affect workflow and visualization are paramount to maximize outcomes.

METHODS

The authors review the nuances of the endoscopic approaches to the various regions of the spine as it relates to the selection of the working channel. The advantages and limitations of various endoscopic working channels were analyzed as to how they address anatomic regional considerations as well as ultimate goals of surgery.

RESULTS

In addition to anatomic regional differences and the goals of the surgery other key elements in endoscopic working channel selection included the amount of tissue disruption, regional risk to the neural elements, impact on visualization, optical physics, and the implications for surgical maneuverability/dexterity.

CONCLUSION

Understanding the role and use of the endoscope-working channel combination with its effects on visualization is essential for any surgeon aspiring to perform safe and efficient full endoscopic spine surgery.

Development of a multi-sensor system for defects detection in additive manufacturing

Defects detection technology is essential for monitoring and hence maintaining the product quality of additive manufacturing (AM) processes; however, traditional detection methods based on single sensor have great limitations such as low accuracy and scarce information. In this study, a multi-sensor defect detection system (MSDDS) was proposed and developed for defect detection with the fusion of visible, infrared, and polarization detection information. The assessment criteria for imaging quality of the MSDDS have been optimized and evaluated. Meanwhile, the feasibility of processing and assembly of each sensor module has been demonstrated with tolerance sensitivity and the Monte Carlo analysis. Moreover, multi-sensor image fusion processing, super-resolution reconstruction, and feature extraction of defects are applied. Simulation and experimental studies indicate that the developed MSDDS can obtain high contrast and clear key information, and high-quality detected images of AM defects such as cracking, scratches, and porosity can be effectively extracted. The research provides a helpful and potential solution for defect detection and processing parameter optimization in AM processes such as Selective Laser Melting.

Optimizing Visualization in Endoscopic Spine Surgery

Given the inherent limitations of spinal endoscopic surgery, proper lighting and visualization are of tremendous importance. These limitations include a small field of view, significant potential for disorientation, and small working cannulas. While modern endoscopic surgery has evolved in spite of these shortcomings, further progress in improving and enhancing visualization must be made to improve the safety and efficacy of endoscopic surgery. However, in order to understand potential avenues for improvement, a strong basis in the physical principles behind modern endoscopic surgery is first required. Having established these principles, novel techniques for enhanced visualization can be considered. Most compelling are technologies that leverage the concepts of light transformation, tissue manipulation, and image processing. These broad categories of enhanced visualization are well established in other surgical subspecialties and include techniques such as optical chromoendoscopy, fluorescence imaging, and 3-dimensional endoscopy. These techniques have clear applications to spinal endoscopy and represent important avenues for future research.

Adjustable-focus ultracompact endoscopic lens design with ultrahigh optical performance

An internally focusing design is developed for a compact endoscopic lens to have optical performance close to the diffraction limit. When changing the working distance from infinity to a predetermined short distance, the overall system length and the field of view remain constant. It is numerically demonstrated that the diffraction-limit-like performance is maintained over a wide range of working distances, showing a novel capability of adjustable focuses. The design concept is numerically proven to be feasible and can enable very high-resolution examination for doctors checking the positions of biological entities through the immediate capture of clear images at different working distances. The corresponding lens configuration, PNN, is shown to be useful in achieving the high-resolution performance once the number of lens elements is four, where P and N are used to denote positive and negative optical power, respectively, for the lens groups. A corresponding tolerance analysis is also presented.

Continuously zoom imaging probe for the multi-resolution foveated laparoscope

In modern minimally invasive surgeries (MIS), standard laparoscopes suffer from the tradeoff between the spatial resolution and field of view (FOV). The inability of simultaneously acquiring high-resolution images for accurate operation and wide-angle overviews for situational awareness limits the efficiency and outcome of the MIS. A dual view multi-resolution foveated laparoscope (MRFL) which can simultaneously provide the surgeon with a high-resolution view as well as a wide-angle overview was proposed and demonstrated to have great potential for improving the MIS. Although experiment results demonstrated the high-magnification probe has an adequate magnification for viewing surgical details, the dual-view MRFL is limited to two fixed levels of magnifications. A fine adjustment of the magnification is highly desired for obtaining high resolution images with desired field coverage. In this paper, a high magnification probe with continuous zooming capability without any mechanical moving parts is demonstrated. By taking the advantages of two electrically tunable lenses, one for optical zoom and the other for image focus compensation, the optical magnification of the high-magnification probe varies from 2 × to 3 × compared with that of the wide-angle probe, while the focused object position stays the same as the wide-angle probe. The optical design and the tunable lens analysis are presented, followed by prototype demonstration.