If a scanning illumination spot is combined with a detector array, we acquire a 4 dimensional signal. Unlike confocal microscopy with a small pinhole, we detect all the light from the object, which is particularly important for fluorescence microscopy, when the signal is weak. The image signal is basically a cross-correlation, and is highly redundant. It has more than sufficient information to reconstruct an improved resolution image. A 2D image can be generated from the measured signal by pixel reassignment. The result is improved resolution and signal strength, the system being called image scanning microscopy. A variety of different signal processing techniques can be used to predict the reassignment and deconvolve the partial images. We use an innovative single-photon avalanche diode (SPAD) array detector of 25 detectors (arranged into a 5x 5 matrix). We can simultaneously acquire 25 partial images and process to calculate the final reconstruction online.
Publication Details Citation
Sheppard, C. J., Buttafava, M., Castello, M., Diaspro, A., Tortarolo, G., Tosi, A., Vicidomini, G., & Villa, F. (2018). Image scanning microscopy (ISM) with a single photon avalanche diode (SPAD) array detector. Faculty of Science, Medicine and Health - Papers: Part B. https://doi.org/10.1117/12.2309825. Retrieved from https://ro.uow.edu.au/smhpapers1/188