Time-extracted non-contact imaging. (a) Schematic of brain blood flow captured with the zero-contact SLICE camera. (b) Component parts of the camera. (c) Principle of capturing deep tissue images with a compact camera using ordinary laser diodes. (d) Modelling of light propagation in a simplified head model to analyse the influence of the pulse width of the input illumination. The size of the illuminated region is 64 × 18 mm. The detector, measuring 1 × 1 mm, is located in the centre of the illuminated region. Both were placed on the top surface of the phantom. The thickness and optical properties of each layer of the phantom are shown in Table 1. The mean optical path length of propagated light which passes the brain layer between 0–4 mm in depth was computed using a Monte Carlo simulation. (e) Relationship between arrival time of the returned light to the detector and mean partial optical path length. 0 ns on the time axis indicates that the pulsed light was turned off. Pulse widths of the input illumination were 1 ps and 10 ns. (f) Waveform of a laser pulsed light and the shutter driving signal of the SLICE camera, measured using a two-channel oscilloscope (Tektronix DPO 7254). Laser-pulsed light was detected with a photo detector and transformed from light intensity to a voltage level. Scale bars: 10 ns.