Advances in iterative non-uniformity correction techniques for infrared scene projection

Abstract

Santa Barbara Infrared (SBIR) is continually developing improved methods for non-uniformity correction (NUC) of its Infrared Scene Projectors (IRSPs) as part of its comprehensive efforts to achieve the best possible projector performance. The most recent step forward, Advanced Iterative NUC (AI-NUC), improves upon previous NUC approaches in several ways. The key to NUC performance is achieving the most accurate possible input drive-toradiance output mapping for each emitter pixel. This requires many highly-accurate radiance measurements of emitter output, as well as sophisticated manipulation of the resulting data set. AI-NUC expands the available radiance data set to include all measurements made of emitter output at any point. In addition, it allows the user to efficiently manage that data for use in the construction of a new NUC table that is generated from an improved fit of the emitter response curve. Not only does this improve the overall NUC by offering more statistics for interpolation than previous approaches, it also simplifies the removal of erroneous data from the set so that it does not propagate into the correction tables. AI-NUC is implemented by SBIR's IRWindows4 automated test software as part its advanced turnkey IRSP product (the Calibration Radiometry System or CRS), which incorporates all necessary measurement, calibration and NUC table generation capabilities. By employing AI-NUC on the CRS, SBIR has demonstrated the best uniformity results on resistive emitter arrays to date.

Nonuniformity-Immune Read-In Integrated Circuit for Infrared Sensor Testing Systems

“…Comparing Figure 8a,b, the temperature difference between pixels decreases when using the proposed circuit structure. In particular, the maximum temperature difference decreased from 112 to 0.5 K. The nonuniformity, which can be calculated with Equation (8) [9], was plotted as a function of the apparent temperature, as shown in Figure 10.…”

“…The highest nonuniformity value for a conventional RIIC was 21%, however, when the proposed structure was used, this quantity became lower than 0.1%. This value, therefore, is The nonuniformity, which can be calculated with Equation (8) [9], was plotted as a function of the apparent temperature, as shown in Figure 10.…”

“…Currently, the look-up table (LUT) method is used to reduce the nonuniformity at each pixel [8][9][10][11][12][13][14]; however, as the radiance range of the overall pixels must be standardized to alower value to achieve uniform radiation, the performance of this method is hindered for a wide radiance range of IRSPs. Therefore, to obtain high-quality IR images for wide radiance ranges, a nonuniformity reduction in emitters and ICs is required in addition to external correction.…”

“…To improve circuit uniformities, several RIICs that adopt current-programming methods have been suggested [15,16]. However, to ensure the simultaneous IR emission of pixels [9,10], two transistors are separately needed for data sampling and current driving, hindering precise RIIC nonuniformity reduction.…”