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Nicholas Califano

Publications and source records attributed to Nicholas Califano.

8 records
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

3D Localization of Defects in Facility Inspection

Wind tunnels are crucial facilities that support the aerospace industry. However, these facilities are large, complex, and pose unique maintenance and inspection requirements. Manual inspections to identify defects such as cracks, missing fasteners, leaks, and foreign objects are important but labor and schedule intensive. Our goal is to utilize small Unmanned Aircraft Systems (sUAS) and computer vision-based analysis to automate the inspection of the interior and exterior of NASA’s critical wind tunnel facilities. We detect missing fasteners as our defect class, and detect existing fasteners to provide potential future missing fastener sites for preventative maintenance. These detections are done on both 2D raw images and in 3D space to provide a visual reference and real world location to facilitate repairs. A dataset was created consisting of images taken along a grid-like pattern of an interior tunnel section in the AEDC National Full-Scale Aerodynamics Complex (NFAC) at NASA Ames Research Center. Our method uses object detection to create image level bounding boxes of the fasteners and missing fasteners, then uses photogrammetry to create a mapping from 2D image locations to 3D real world locations. The image level bounding boxes and the 2D to 3D mapping are then combined to determine the 3D location of the defects. We describe the data collection, photogrammetry, and computer vision techniques used for object detection as well as a quantitative analysis of the method.

Small Unmanned Aircraft Systems (sUAS)↗
NASA NTRSDate not supplied

Unsteady Pressure Sensitive Paint Camera Calibration Improvements

Data collection using unsteady pressure-sensitive paint (uPSP) has been greatly increased in recent large-scale demonstrations. With this significant increase comes challenges to process this magnitude of data. Techniques designed for several thousands of images collected in a lab do not necessarily scale to millions collected in a production-level system. Novel techniques are needed to meet the tighter requirements imposed on computation time, robustness, and accuracy. This paper outlines a number of such techniques and improvements in regards to the camera calibration process.

Camera calibration↗
NASA NTRSDate not supplied

Unsteady Pressure Sensitive Paint Camera Calibration Improvements

New challenges have arisen in processing a significantly increased volume of data collected during recent large-scale demonstrations of unsteady pressure-sensitive paint. Techniques designed for several thousands of images collected in a lab do not necessarily scale to tens of millions collected in a large-scale test. New techniques are needed to meet the tighter requirements on robustness and accuracy that accompany larger wind tunnel models, higher camera resolution, and more run conditions per test. This paper outlines several such techniques and improvements in regard to the camera calibration process.

Camera calibration↗
NASA NTRSDate not supplied

Unsteady Pressure Sensitive Paint Camera Calibration Improvements

New challenges have arisen in processing a significantly increased volume of data collected during recent large-scale demonstrations of unsteady pressure-sensitive paint. Techniques designed for several thousands of images collected in a lab do not necessarily scale to tens of millions collected in a large-scale test. New techniques are needed to meet the tighter requirements on robustness and accuracy that accompany larger wind tunnel models, higher camera resolution, and more run conditions per test. This paper outlines several such techniques and improvements in regard to the camera calibration process.

Camera calibration↗
NASA NTRSDate not supplied

Infrared Reflection Removal in Wind Tunnels using Polarization Theory

Infrared radiometry with infrared cameras allows for high spatial resolution, noncontact measurements in wind tunnel experiments and has been increasingly used to visualize flow features. Reflections from test section walls present a major challenge in collecting these measurements as it is difficult or impossible to separate them from the true model emission signal. This paper implements a method to quantitatively separate the reflections from the emission using polarization theory. Samples with a range of emissivities were tested, and in all samples the reflections were significantly reduced. This method will lead to more accurate radiometric and thermographic measurements in wind tunnel experiments.

Infrared↗
NASA NTRSDate not supplied

Advancements in the Camera Setup for Unsteady Pressure Sensitive Paint at NASA Ames Research Center

A test in the Unitary Plan Wind Tunnel at NASA Ames Research Center is scheduled for early 2024 with the intent of showcasing improvements made to unsteady Pressure Sensitive Paint technology. Analysis was performed to investigate how to maximize the system resolving power by optimizing the camera parameters, specifically focal length and focusing distance, while still subject to other system requirements such as field of view and relatively low illumination from the paint. Additionally, the system is upgrading to an 8-camera system from a 4-camera system, so analysis was performed to determine the best way to extend that system to maximize camera coverage and how to most effective reduce the system uncertainty by averaging multiple measurement using camera overlap. These analyses have uncovered new opportunities to improve the unsteady Pressure Sensitive Paint technology without the need for new or expensive hardware and will allow the system to collect better data with simple changes to the design process.

Camera Calibration↗
NASA NTRSDate not supplied

Camera Setup for Unsteady Pressure Sensitive Paint at NASA Ames Research Center

The unsteady Pressure-Sensitive Paint Development Team at NASA Ames Research Center is conducting a Launch Vehicle Demo Test in the Unitary Plan Wind Tunnel’s 11-ft Transonic Wind Tunnel in the first half of 2024 to showcase improvements made to unsteady Pressure-Sensitive Paint technology. The unsteady Pressure-Sensitive Paint setup has upgraded from a four-camera system to an eight-camera system, prompting analysis to maximize the system performance and overall data quality. Additional analysis was performed to maximize the system resolving power when subject to test constraints such as model size and model tunnel positions. These analyses have uncovered new opportunities to improve the unsteady Pressure-Sensitive Paint technology and will allow the system to collect higher quality data with simple changes to the setup procedure.

Camera Calibration↗