Optical design and system engineering of a multiresolution foveated laparoscope

A Serious Game to Study Reduced Field of View in Keyhole Surgery: Development and Experimental Study

BACKGROUND

During keyhole surgery, the surgeon is required to perform highly demanding tasks while only being able to see part of the patient's anatomy. This limited field of view is widely cited as a key limitation of the procedure, and many computational methods have been proposed to overcome it. However, the precise effects of a limited field of view on task performance remain unknown due to the lack of tools to study these effects effectively.

OBJECTIVE

This paper describes our work on developing a serious game with 2 objectives: (1) to create an engaging game that communicates some of the challenges of keyhole surgery, and (2) to test the effect of a limited field of view on task performance. The development of a serious game that can be played by a wide range of participants will enable us to gather quantitative data on the effects of the reduced field of view on task performance. These data can inform the future development of technologies to help surgeons reduce the impact of a limited field of view on clinical outcomes for patients. The game is open source and may be adapted and used by other researchers to study related problems.

METHODS

We implemented an open-source serious game in JavaScript, inspired by the surgical task of selectively cauterizing blood vessels during twin-to-twin transfusion surgery. During the game, the player is required to identify and cut the correct blood vessel under different fields of view and varying levels of vascular complexity. We conducted a quantitative analysis of task performance time under different conditions and a formative analysis of the game using participant questionnaires.

RESULTS

We recruited 25 players to test the game and recorded their task performance time, accuracy, and qualitative metrics. Reducing the field of view resulted in participants taking significantly longer (P<.001) to perform otherwise identical tasks (mean 6.4 seconds, 95% CI 5.0-7.8 seconds vs mean 13.6 seconds, 95% CI 10.3-16.9 seconds). Participants found the game engaging and agreed that it enhanced their understanding of the limited field of view during keyhole surgery.

CONCLUSIONS

We recruited 25 players to test the game and recorded their task performance time, accuracy, and qualitative metrics. Reducing the field of view resulted in participants taking statistically significantly longer (16.4 vs 9.8 seconds; P=.05) to perform otherwise identical tasks. Participants found the game engaging and agreed that it enhanced their understanding of the limited field of view during keyhole surgery.

A dual-view multi-resolution laparoscope for safer and more efficient minimally invasive surgery

Minimally invasive surgery (MIS) is limited in safety and efficiency by the hand-held nature and narrow fields of view of traditional laparoscopes. A multi-resolution foveated laparoscope (MRFL) was invented to address these concerns. The MRFL is a stationary dual-view imaging device with optical panning and zooming capabilities. It is designed to simultaneously capture and display a zoomed view and supplemental wide view of the surgical field. Optical zooming and panning capabilities facilitate repositioning of the zoomed view without physically moving the system. Additional MRFL features designed to improve safety and efficiency include its snub-nosed endoscope, tool-tip auto tracking, programmable focus profiles, unique selectable display modalities, foot pedal controls, and independently controlled surgeon and assistant displays. An MRFL prototype was constructed to demonstrate and test these features. Testing of the prototype validates its design architecture and confirms the functionality of its features. The current MRFL prototype functions adequately as a proof of concept, but the system features and performance require further improvement to be practical for clinical use.

High-throughput multi-resolution foveated laparoscope for minimally invasive surgery

Feasibility and clinical utility of a multi-resolution foveated laparoscope (MRFL) was previously tested in a porcine surgical study. The study revealed several clinical limitations of the system including moisture proofing, working distance, image quality, low light performance, color accuracy, size, and weight. In this paper, we discuss the root causes of these limitations and strategies to correct them, present the design and prototyping of a new high throughput multi resolution foveated laparoscope (HT-MRFL), and demonstrate the HT-MRFL prototype performance in comparison to the MRFL and simulated performance metrics.

Prism-based tri-aperture laparoscopic objective for multi-view acquisition

This paper presents the design and prototype of a novel tri-aperture monocular laparoscopic objective that can acquire both stereoscopic views for depth information and a wide field of view (FOV) for situational awareness. The stereoscopic views are simultaneously captured via a shared objective with two displaced apertures and a custom prism. Overlapping crosstalk between the stereoscopic views is diminished by incorporating a strategically placed vignetting aperture. Meanwhile, the wide FOV is captured via a central third aperture of the same objective and provides a 2D view of the surgical field 2x as large as the area imaged by the stereoscopic views. We also demonstrate how the wide FOV provides a reference data set for stereo calibration, which enables absolute depth mapping in our experimental prototype.

Optical design and stray light control for a space-based laser space debris removal mission

In low-Earth orbit, the already existing population of small and medium debris (between 1 cm and several dozens of cm) is a concrete threat to operational satellites. A space-based laser space debris removal (SLDR) system that can remove hazardous debris around selected space assets appears to be a flexible and effective project. To achieve high-precision tracking and emitting, the optical system of the SLDR mission includes a target-detection telescope and emitting telescope, adopting a common light path structure. The optical design results, system performance, tolerance budget, and detailed stray light control design are presented in this paper. The large-aperture off-axis two-mirror beam-narrowing system characteristics are also discussed in terms of stray light control. This paper will present the lateral-displacement (LD) setting, two-stage fore baffle design, black baffle surface selection, and opening direction of the telescope door. The results showed that the stray light elimination reaches a 10^-9 order, meeting design requirements.

Further Comparison of 4 Display Modes for a Multi-Resolution Foveated Laparoscope

Background. To overcome field of view and ergonomic limitations of standard laparoscopes, we are developing a multi-resolution foveated laparoscope (MRFL), which can simultaneously obtain both wide- and zoomed-in-view images. To facilitate the effectiveness of our MRFL, we have been investigating various ways of organizing and visualizing dual-view multi-resolution images acquired by the MRFL. In our prior study, we implemented and compared 6 display modes for the MRFL, assuming a typical clinical environment where a standard (but limited) resolution monitor is available. To take full advantage of our MRFL, displays having sufficient screen resolutions might be advantageous. The present study aims to further understand the effects of view configurations through displays with a standard high-definition (HD) resolution and a 4K resolution. In this study, we compare 3 display modes for limited-resolution displays against a new mode for sufficient-resolution displays. Methods. Twenty subjects performed 3 evaluation trials of a touching task with each display mode in an emulated MRFL environment. Various objective measurements including task completion time and the number of collisions, and subjective preference were recorded. Results. The new mode showed a better task completion time than the other modes, while it maintained a low number of collisions similar to the others. Moreover, the majority of participants selected the new mode as their most preferred one. Conclusions. With a sufficient display resolution, the co-registration between the unblocked and unwarped wide context view and the high-resolution zoomed-in view offered by the new mode was highly effective on both task performance and user preference.

Improved multi-resolution foveated laparoscope with real-time digital transverse chromatic correction

A multi-resolution foveated laparoscope (MRFL) with autofocus and zooming capabilities was previously designed to address the limiting trade-off between spatial resolution and field of view during laparoscopic minimally invasive surgery. The MRFL splits incoming light into two paths enabling simultaneous capture of the full surgical field and a zoomed-in view of the local surgical site. A fully functional prototype was constructed to demonstrate and test the autofocus, zooming capabilities, and clinical utility of this new laparoscope. The test of the prototype in both dry lab and animal models was successful, but it also revealed several major limitations of the prototype. In this paper, we present a brief overview of the aforementioned MRFL prototype design and results, and the shortcomings associated with its optical and mechanical designs. We then present several methods to address the shortcomings of the existing prototype with a modified optical layout and redesigned mechanics. The performances of the new and old system prototypes are comparatively analyzed in accordance with the design goals of the new MRFL. Finally, we present and demonstrate a real-time digital method for correcting transverse chromatic aberration to further improve the overall image quality, which can be adapted to future MRFL systems.

Optical design of the visible telescope for the SVOM mission

This paper describes the optical design of the visible telescope (VT), which is the primary payload for the Chinese-French Space-based multi-band astronomical Variable Objects Monitor (SVOM) mission, for the detection and observation of high-redshift gamma-ray bursts. The VT aims at reaching a limiting magnitude of +22.5Mv with the exposure time of 300 s in the 630 km Sun-synchronous orbit with an inclination of 30°. The VT, also known as the fine guidance sensor for the SVOM, aims to measure the relative performance error (RPE) of the platform during the tracking and provide the RPE to the platform to correct its stability. The optical design is presented in this paper. The mirror manufacture and test results are presented. The optical system performance, tolerance budget, thermal analysis, and stray light design of VT are fully analyzed. Finally, the diffraction encircled energy and point source transmittance are tested in the lab for the finished telescope.