Course Description This is an advanced course in which we explore the field of Statistical Optics. Topics covered include such subjects as the statistical properties of natural (thermal) and laser light, spatial and temporal coherence, effects of partial coherence on optical imaging instruments, effects on imaging due to randomly inhomogeneous media, and a statistical treatment of the detection of light. Development of this more comprehensive model of the behavior of light draws upon the use of tools traditionally available to the electrical engineer, such as linear system theory and the theory of stochastic processes.

http://ieeexplore.ieee.org/iel5/3/23094/01073023.pdf

Statistical optics

Mesoscopic Physics Of Electrons And Photons

We report that disordered media made of randomly distributed nanoparticles can be used to overcome the diffraction limit of a conventional imaging system. By developing a method to extract the original image information from the multiple scattering induced by the turbid media, we dramatically increase a numerical aperture of the imaging system. As a result, the resolution is enhanced by more than 5 times over the diffraction limit, and the field of view is extended over the physical area of the camera. Our technique lays the foundation to use a turbid medium as a far-field superlens.

Overcoming the Diffraction Limit Using Multiple Light Scattering in a Highly Disordered Medium

The present invention discloses a camera array-based light field microscopic imaging system and method. The system includes a microscope which enlarges a microscopic sample to an image plane through a cameral lead-out opening, an enlargement module which can generate an aperture plane, an imaging lens array which obtains sample images of the microscopic sample under different angles of view, a sensor array wherein each sensor correspondingly records a sample image obtained by an imaging lens corresponding to the sensor, and a controller which acquires and calibrates the sample images synchronously so as to obtain the light field and/or light field video of the microscopic sample. According to the camera array-based light field microscopic imaging system and method provided by the embodiment of the invention, the sample images of the microscopic sample under different angles of view are obtained and calibrated, so that the light field and/or light field video of the microscopic scene can be obtained, and therefore, high-performance microscopic imaging and application can be realized, and spatial resolution can be improved, and use experience of users can be also improved.

Camera array-based light field microscopic imaging system and method

The invention discloses a random scattering correlated imaging system based on LED illumination, and an imaging method thereof. The random scattering correlated imaging system mainly settles the problems of high requirement for a light source, complicated imaging system and low real-time performance in imaging in prior art. The imaging system comprises the components of an LED light source (1), a collimating lens (2), a first variable diaphragm (3), an observing target (4), a random scattering medium (5), a second variable diaphragm (6), a narrowband filter plate (7) and a detector array (8). Incoherent light which is emitted from the LED light source penetrates through the collimating lens and arrives at the first variable diaphragm, and the light which penetrates through the first variable diaphragm is irradiated to the observing target. The light which carries target information enters the random scattering medium. The emergent light penetrates through the second variable diaphragm for filtering a stray light and then enters the narrowband filter plate. Finally a speckle image is formed on the detector array. The random scattering correlated imaging system and the imaging method have advantages of low imaging cost, simple imaging structure and high real-time performance in imaging. The random scattering correlated imaging system and the imaging method can be used for the fields of biomedicine, public security and anti-terrorism.

Random scattering correlated imaging system based on LED illumination, and imaging method thereof

The invention discloses a structural illumination-based random scattering optical beyond-diffraction-limit imaging system and method. The objective of the invention is mainly to solve the problems of complicated techniques, long imaging time, difficult realization of system structure and low imaging resolution of existing similar technologies. The imaging system includes a light source, a beam expander, a spatial light modulator, a lambda/4 wave plate, a beam expanding lens group, a light blocking plate, lenses, a random scattering medium, a convergence lens, and a CCD camera; light beams emitted by the light source are subjected to beam expansion of the beam expander and thereafter enter the spatial light modulator, so that 0-level light and +/-1-level light are obtained; the 0-level light and +/-1-level light pass through the lambda/4 wave plate, so that circularly polarized light can be obtained; after being subjected to beam expansion of the beam expanding lens group, the circularly polarized light reaches the light blocking plate, and the +/-1-level light is reserved; the +/-1-level light is interfered when passing through the lenses, and structural light can be generated, and an observation target can be illuminated; and the illuminated observation target enters the random scattering medium, and strong scattering occurs, and light beams enter the CCD camera through the convergence lens. The structural illumination-based random scattering optical beyond-diffraction-limit imaging system of the invention has the advantages of simple structure and high imaging resolution, and can be used for optical super resolution imaging.

Structural illumination-based random scattering optical beyond-diffraction-limit imaging system and method

The invention discloses an ultrahigh resolution wide-field imaging system which mainly solves the problems that the resolution ratio is low and the view field distorts seriously in the prior art. The ultrahigh resolution wide-field imaging system comprises a holocentric spherical main objective lens (11), a tiny camera array (12), a detector array (13), a tiny camera control module (14), an image splicing module (21), a displayer (22) and a memorizer (23). Incident light sequentially passes through the holocentric spherical main objective lens (11) and the tiny camera array (12) and reaches the detector array (13) for imaging. The tiny camera control module (14) sends images generated on the detector array (13) to the image splicing module (21), and the image splicing module (21) splices the images to obtain the images wide in view field and high in resolution. The memorizer (23) stores the images high in resolution, and the images high in resolution are displayed through the displayer (22). The ultrahigh resolution wide-field imaging system has the advantages of being simple in structure, wide in view field, high in resolution, and capable of being applied to space monitoring, supervisory control, detection and warning.

Ultrahigh resolution wide-field imaging system

We address an optical imaging method that allows imaging, which owing to the “memory-effect” for speckle correlations, through highly scattering turbid media with “Error Reduction - Hybid Input Ouput (ER-HIO)” algorithm When light propagates through the opaque materials, such as white paint, paper or biological tissues, it will be scattered away due to the inhomogeneity of the refractive index Multiple scattering of light in highly scattering media forms speckle field, which will greatly reduce the imaging depth and degrade the imaging quality Some methods have been developed to solve this problem in recent years, including wavefront modulation method (WMM), transmission matrix method (TMM) and speckle correlations method (SCM) A novel approach is proposed to image through a highly scattering turbid medium, which combines speckle correlations method (SCM) with phase retrieval algorithm (PRA) Here, we show that, owing to the “optical memory effect” for speckle correlations, a single frame image of the speckle field, captured with a high performance detector, encodes sufficient information to image through highly scattering turbid media Theoretical and experimental results show that, neither the light source, nor wave-front shaping is required in this method, and that the imaging can be easily realized here using just a simple optical system with the help of optical memory effect Our method does not require coherent light source, which can be achieved with LED illumination, unlike previous approaches, and therefore is potentially suitable for more and more areas Consequently, it will be beneficial to achieve imaging in currently inaccessible scenarios

Speckle-correlation imaging through highly scattering turbid media with LED illumination

The invention discloses a random scattering optical imaging system and a random scattering optical imaging method based on sparse representation. The imaging system comprises a light source (1), a spatial filter (2), an aperture diaphragm (3), a collimating lens (4), a reflector (5), a spatial light modulator (6), a random scattering medium (7), a lens (8), a detector array (9), and a main control computer (10). Light emitted by the light source enters the spatial light modulator via the reflector after passing through the spatial filter, the aperture diaphragm and the collimating lens. The main control computer loads an imaging target on the spatial light modulator, so that light emitted from the spatial light modulator and carrying target information forms a coding speckle field image on the detector array after passing through the random scattering medium and the lens, and the coding speckle field image is transmitted to the main control computer. The main control computer decodes and reconstructs the coding speckle field image and removes background noise to obtain a target image. The random scattering optical imaging system of the invention has a simple structure, good real-time performance and high noise resistance. The system and the method of the invention can be used for random scattering high-speed imaging in a noise environment in the laboratory.

Weijia Dai

Papers

Structural illumination-based random scattering optical beyond-diffraction-limit imaging system and method

Random scattering correlated imaging system based on LED illumination, and imaging method thereof

Ultrahigh resolution wide-field imaging system

Speckle-correlation imaging through highly scattering turbid media with LED illumination

Random scattering optical imaging system and random scattering optical imaging method based on sparse representation