Milliseconds Photon-to-Photon Latency Projection System for Adaptive Optogenetics Applications

In recent years, Dynamic Projection Mapping (DPM), which dynamically and adaptively projects images to suit moving and transforming objects, has attracted much attention. There is another case in which similar projection is necessary for objects under a microscope. Optogenetics can make certain cells photosensitive by genetic modification, and this can be used to input a disturbance to the cells. In particular, when the subject is in motion, the position of the cells to be stimulated changes in accordance with the motion or deformation of the subject, and the projection pattern must be changed dynamically to match this position. This requirement is exactly the same requirement as in DPM. Therefore, in this paper, we propose a projection method for microscopy with milliseconds latency. The proposed method is based on a low-latency Digital Micromirror Device (DMD) and high-speed vision system to achieve light projection that responds to deformation and movement of the object. A developed prototype system demonstrated a total latency ≤ 6.27 ms. Furthermore, dynamic projection mapping on a randomly moving target was also successfully demonstrated.