Low-cost open-source camera view splitter (quadscope) for flow diagnostics

Camera view splitters use optical engineering to cast multiple images of a single target onto a single camera. For experiments in fluid dynamics, the ability to perform multivariate and multidimensional measurements is key to effectively studying complex thermofluidic phenomena. Generating multiple target views onto a single camera is a good way to reduce system costs by using fewer cameras. Currently, view splitting requires the purchase of expensive commercial lenses or the in-house design and fabrication of custom components, hindering the pace of research and development. Here, we provide an open-source design for a low-cost, general-purpose view splitter, providing up to four views per camera. All custom parts for the assembly are provided, which are designed for easy integration with standard optical components. Additional files are included for different view splitter orientations (designed for tomography) and the optional integration with spectral filtering. Characterization experiments were performed at multiple object distances to determine changes in image mapping quality, parallax angles, pixel density, and field-of-view (FOV). Validation is performed on a non-premixed methane/air flame, demonstrating the ability of the view splitter to perform simultaneous high-speed imaging and quantitative measurement in a practical system. This assembly has the potential to democratize access to advanced imaging capability and accelerate progress in the broader diagnostics community.