Our study employs a simulation technique (‘hybrid simulation’), which combines sensor imagery of real environments with virtual objects to generate realistic target imagery for signature assessment. This method is preferred over entirely virtual scenes, for which it can be challenging to replicate reality with sufficient fidelity. In prior research, we investigated three methods for creating hybrid scenes using Unity software: i) using recordings of a scale-model of the target within the scene, ii) using material capture, which involves recording probe spheres in the scene to map colors directly onto the virtual target and iii) combining 360-degree light field measurements with BRDF measurements to integrate a virtual target into the scene. Although the hybrid scenes demonstrated reasonable agreement with the validation scenes, discrepancies both in color and luminance were observed. To address this, we replaced the Unity rendering engine with the validated RADIANCE lighting simulation raytracing engine. In this study, hybrid scenes are rendered using the RADIANCE engine and compared to validation scenes. Additionally, we introduce a second layer of interaction that enables the virtual target to affect the recorded imagery. As a result, the virtual target can now create shadows and affect the appearance of the recorded imagery. The combined improvement of the rendering engine and the inclusion of the interaction between the virtual target and real environment has resulted in more realistic scenes, making them more appropriate for camouflage assessment.
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