Single-pixel imaging through non-homogeneous turbid media with adaptive illumination

The presence of scattering media limits the quality of images obtained by optical systems. Single-pixel imaging techniques based on structured illumination are highly tolerant to the presence of scattering between the object and the sensor, but very sensitive when the scattering medium is between the light source and the object. This makes it difficult to develop single-pixel imaging techniques for the case of objects immersed in scattering media. We present what we believe to be a new system for imaging objects through inhomogeneous scattering media in an epi-illumination configuration. It works in an adaptive way by combining diffuse optical imaging (DOI) and single pixel imaging (SPI) techniques in two stages. First, the turbid media is characterized by projecting light patterns with an LED array and applying DOI techniques. Second, the LED array is programmed to project light only through the less scattering areas of the media, while simultaneously using a digital micromirror device (DMD) to project light patterns onto the target using Hadamard basis coding functions. With this adaptive technique, we are able to obtain images of targets through two different scattering media with better quality than using conventional illumination. We also show that the system works with fluorescent targets.