A unified near- and far-field imaging model for rotating modulation collimators

Rotating modulation collimators (RMCs) are a class of imaging devices that have been applied to both gamma ray astronomy (far field) and medical imaging (very near field). To reconstruct images from these devices, it is necessary to understand the imaging system model and how the radiation source is modulated. In both the near and far fields, simplifying approximations can allow for closed form transmission functions. This research presents a new method for identifying the RMC imaging system model. Results are compared to existing far field models as well as measured data. The new method removes many of the constraints assumed for previous models (infinite extent, uniform slits, black masks, etc.), allowing for potential studies on new classes of RMCs and mask designs. Published by Elsevier B.V.