Single pixel imaging at megahertz switching rates via cyclic Hadamard masks

Abstract

Optical imaging is commonly performed with either a camera and wide-field illumination or with a single detector and a scanning collimated beam; unfortunately, these options do not exist at all wavelengths. Single-pixel imaging offers an alternative that can be performed with a single detector and wide-field illumination, potentially enabling imaging applications in which the detection and illumination technologies are immature. However, single-pixel imaging currently suffers from low imaging rates owing to its reliance on configurable spatial light modulators, generally limited to 22 kHz rates. We develop an approach for rapid single-pixel imaging which relies on cyclic patterns coded onto a spinning mask and demonstrate it for in vivo imaging of C. elegans worms. Spatial modulation rates of up to 2.4 MHz, imaging rates of up to 72 fps, and image-reconstruction times of down to 1.5 ms are reported, enabling real-time visualization of dynamic objects.

Gigahertz-rate random speckle projection for high-speed single-pixel image classification

“…While SLMs with a large number of pixels enable a wide variety of illumination pattern controls, the low refresh rate, which is typically on the order of ∼10 kHz, ultimately limits the image processing speed. In response, significant effort has been devoted to increasing the refresh rate of the pattern illumination for high-speed ghost imaging and singlepixel image processing [12][13][14][15][16][17][18].…”

Single pixel imaging at high pixel resolutions

“…Far higher frame-rates are possible with structured illumination with LEDs arrays, although such setups for ghost imaging and SPI have been demonstrated only at low resolutions [10][11][12][13]. Modulation with rotary elements with fixed patterns is a high-speed cost-efficient alternative to using dynamic modulators in THz [14][15][16]. The modulation speed may be also increased by combining various light modulation techniques together or by using arrayed light sources with a fast modulation rate [17,18].…”

Using an Acousto-Optic Modulator as a Fast Spatial Light Modulator

“…Studies have attempted to reduce acquisition time through compressed sensing [14,18] and intensity estimation from limited photon detection [19], but the speed of SPI is still fundamentally limited by the refresh rate of the SLM. Compressed imaging with pattern modulation rates in excess of 1 MHz has been demonstrated [20] using a spinning mask, resulting in an image acquisition rate of 72 Hz with 101 × 103 pixels resolution. One drawback of the approach in [20] is that the illumination patterns are fixed and are always generated in the same order, preventing the use of adaptive or compressive sampling techniques.…”

“…Compressed imaging with pattern modulation rates in excess of 1 MHz has been demonstrated [20] using a spinning mask, resulting in an image acquisition rate of 72 Hz with 101 × 103 pixels resolution. One drawback of the approach in [20] is that the illumination patterns are fixed and are always generated in the same order, preventing the use of adaptive or compressive sampling techniques. The development of an SLM with higher efficiency and damage threshold would therefore be particularly valuable for imaging over longer distances and in more complex environments.…”