Multi-Edge Slant Target for Non-Localized MTF Measurement

NASA’s Multi-Edge Slant Target is a precision-manufactured 1-inch diameter chrome-on-quartz calibration plate featuring a sophisticated geometric pattern optimized for comprehensive MTF analysis. The repeated slant edges allow for MTF to be directly sampled across the sensor in discrete locations, as opposed to solely in the center along a single edge of the image. Once the target plate is imaged, the image files can be used to calculate MTF measurements using standard methods as outlined in ISO 12233. The MTF data can then be visualized as a heatmap, which illustrates image quality of the imaging system as a function of discretely localized optical aberrations or spatial non-uniformities in the system’s electro-optical assembly. Fabricated using advanced laser lithography techniques with sub-micron precision, NASA’s target provides exceptional contrast ratios meeting ISO 12233 standards. The chrome coating creates sharp, high-contrast edges on a clear quartz substrate, enabling backlit operation with blackbody or integrating sphere sources across broad spectral ranges. The target's unique geometric design includes positioning markers for precise alignment and multiple sampling regions that enable enhanced MTF measurement accuracy. NASA’s Multi-Edge MTF Slant Target can be used in any application requiring characterization of 2D imaging systems from UV-VIS to MWIR. Firms that develop multi-spectral, hyper-spectral, thermal, and visible light imaging systems may benefit from the full-field spatial performance characterization it enables. Slant targets manufacturers may be interested in adding this capability to their product lines. The invention has been fabricated and validated (it is frequently used by NASA’s SCIFLI team), and is available for patent licensing. High-speed flight, whether by spacecraft, launch vehicles, or hypersonic aircraft, subjects vehicles to extreme thermal, aerodynamic, and structural loads. To refine predictive models and drive improved designs, NASA’s Scientifically Calibrated In-Flight Imagery (SCIFLI) team develops and operates advanced airborne imaging systems that collect high-resolution, multispectral imagery of these flights. Characterizing imager performance is critical to ensuring spatially accurate data is collected. The Modulation Transfer Function (MTF) is a key metric for understanding the quantitative spatial performance (i.e. sharpness and image resolution) of high-precision imaging systems. Conventional slanted-edge MTF targets, however, capture only localized MTF measurements (at the center of the focal plane) or are designed only for the visible light spectrum. Thus, they overlook sharpness variations toward the corners of the focal-plane array and/or have little utility for imaging wavelengths longer than near-infrared. NASA’s new Multi-edge MTF Slant Target provides a solution that fills these gaps. Developed by innovators from NASA Langley Research Center’s SCIFLI team, the target’s array of precisely oriented edges magnified under a large focal length lens span the entire field of view of the sensor, providing global MTF measurements from corner to corner. Materials selection and illumination strategy render the target suitable for measurements from the UV-VIS to MWIR spectra.