A new method from researchers at the Institut National de la Recherche Scientifique (INRS; Varennes, QC, Canada) called single-shot compressed optical-streaking ultra-high-speed photography (COSUP) can increase the imaging speeds for traditional CMOS and CCD cameras by four orders of magnitude. Ultrahigh-imaging speeds of 1.5 million frames per second (fps) with a sequence depth of 500 frames and 0.5 megapixels (1000 × 500 pixels) per frame have been verified through high-speed imaging of a fast-moving ball and laser pulses.
Because traditional imaging techniques fall short of achieving ultrahigh speeds and high pixel counts, COSUP is instead implemented by first imaging a transient scene onto a digital micromirror device (DMD) loaded with a binary pseudorandom pattern (with an encoding pixel size of 32.4 µm2) to create spatially encoded frames that are then relayed onto a CMOS camera by 4f imaging optics. Placing a galvanometer scanner at the Fourier plane of the 4f system temporally shears the images so that the CMOS camera records the spatially encoded, temporally sheared scene as a 2D single-exposure streak image. Linear temporal shearing is accomplished by tuning the sinusoidal function of the galvo scanner to synchronize with the CMOS camera exposure time. A compressed-sensing-based reconstructed algorithm is used to retrieve the transient scene from the acquired streak image. Reference: X. Liu et al., Opt. Lett., 44, 6, 1387–1390 (2019).
