A computational imaging technique that reconstructs images from light intensity measurements without a traditional multi-pixel camera.Single-pixel imaging is a computational imaging technique that reconstructs a full image from a series of light intensity measurements taken with a single detector, rather than using a conventional camera with millions of pixels. Instead of capturing the entire scene at once, it sequentially samples the light field using a series of spatial patterns, then uses algorithms to reconstruct the image from these measurements. This approach is particularly useful in situations where traditional multi-pixel sensors are impractical, such as in certain wavelengths of light (e.g., infrared or terahertz) where array detectors are expensive or unavailable.
The concept was first demonstrated in 2008 by researchers at Rice University, led by Richard Baraniuk and Kevin Kelly, building on the theory of compressed sensing.
The technique works by projecting a series of known spatial patterns onto the scene, one at a time. For each pattern, a single detector measures the total light intensity reflected or transmitted. Each measurement is essentially a weighted sum of the scene's brightness, with the weights determined by the pattern. By collecting enough measurements with different patterns, the system can solve a linear system of equations to reconstruct the image. The key is to use patterns that are efficient, such as random or Hadamard patterns, which allow for good reconstruction with fewer measurements than the number of pixels in the final image.
Single-pixel imaging is used in hyperspectral imaging, terahertz imaging, and imaging through scattering media, where traditional cameras are limited. It is also being explored for use in LiDAR and remote sensing.
Single-pixel cameras can image scenes using only a single detector, which means they can operate at wavelengths where traditional camera sensors are not available, such as in the terahertz range.



















