Jun Tanida

A compact image-capturing system called TOMBO (an acronym for thin observation module by bound optics) is presented in which the compound-eye imaging system is utilized to achieve a thin optical configuration. The captured multiple images are processed to retrieve the image of the target object. For image retrieval, two kinds of processing method are considered: image sampling and backprojection. Computer simulations and preliminary experiments were executed on an evaluation system to verify the

On the basis of a lensless shadow-casting technique, a new, simple method of optically implementing digital logic gates has been developed. These gates are capable of performing a complete set of logical operations on a large array of binary variables in parallel, i.e., the pattern logics. A light-emitting diode (LED) array is used as an incoherent light source in the lensless shadow-casting system. Sixteen possible functions of two binary variables are simply realizable with these gates in para

We present a method for computer-generated holography based on deep learning. The inverse process of light propagation is regressed with a number of computationally generated speckle data sets. This method enables noniterative calculation of computer-generated holograms (CGHs). The proposed method was experimentally verified with a phase-only CGH.

A new optical–digital computing system called OPALS (optical parallel array logic system) is presented. OPALS can execute various parallel neighborhood operations such as cellular logic as well as parallel logical operations for 2-D sampled objects. The system has the ability to perform iterative operations. OPALS is systemized, centering on the optical logic method using image coding and optical correlation techniques. The concept of array logic plays an important role in designing the OPALS, a

Color-imaging methods with an integrated compound imaging system called TOMBO (Thin observation module by bound optics) are presented. The TOMBO is a compact optoelectronic imaging system for image capturing based on compound-eye imaging and post digital processing. First, a general description of the TOMBO system is given, and then two configurations for color imaging are described. Experimental comparison of these configurations is made by use of an experimental TOMBO system. The characteristi

We present a method for noninvasive three-dimensional imaging through scattering media by using a three-dimensional memory effect in scattering phenomena. In the proposed method, an object in a scattering medium is reconstructed from a three-dimensional autocorrelation of speckle images captured by axially scanning an image sensor, based on a three-dimensional phase retrieval algorithm. We experimentally demonstrated our method with a lensless setup by using a three-dimensionally printed object

A novel method of optically implementing parallel neighborhood operations for two-dimensional discrete binary objects is presented. The operations are executed by the optical-array-logic processor (OLAP) based on techniques of imaging coding and optical correlation. The analogy between the mechanism of the OLAP and that of the array logic is efficiently utilized for the method. Any neighborhood operation is easily executed by the OLAP with the help of the concept of array logic. An architecture

We present a machine-learning-based method for light focusing through scattering media. In this method, the optical process in a scattering medium is computationally inverted based on a nonlinear regression algorithm with a number of training input-output pairs through the medium, and an input optimized for a target output is calculated. We experimentally demonstrate focusing via a process involving randomness due to a scattering medium and nonlinearity due to double modulation with a spatial li

Procedures for planning and executing arbitrary parallel processing with optical array logic are generalized as a systematic programming technique of optical parallel processing. Optical array logic is a technique for achieving any parallel neighborhood operation with simple coding and optical correlation. An original symbolic notation facilitates programming of parallel processing with optical array logic, so that many problems can be optically solved using optical array logic. Two examples of

We present a method for single-shot three-dimensional imaging through scattering media with a three-dimensional memory effect. In the proposed computational process, a captured speckle image is two-dimensionally correlated with different scales, and the object is three-dimensionally recovered with three-dimensional phase retrieval. Our method was experimentally demonstrated with a lensless setup and was compared with a multishot approach used in our previous work [Opt. Lett.44, 2526 (2019)OPLEDP

We present a method for observing complex amplitude fields by using a single-pixel camera without reference light and imaging optics. In the method, an object is illuminated with coherent light, and the propagating field is captured in multiple intensity measurements using a single photodetector and a spatial light modulator upon which different patterns are sequentially displayed. The object field is reconstructed from the intensity measurements with a compressive-sensing-based phase retrieval

We present a method for diffractive imaging with a single photodetector and structured illumination based on compressive sensing. A complex-amplitude object is sequentially illuminated with randomly structured coherent light patterns, and the intensities of each propagating field are measured with a single photodetector. This measurement process does not use any reference light or imaging optics. The object complex field is reconstructed from the sequentially measured intensities with an algorit

We present a method of relaxing the conditions of mask design in single-shot phase imaging with a coded aperture (SPICA), for extending the applications of SPICA. SPICA, based on compressive sensing, enables the acquisition of wide, high-resolution optical complex fields in a single exposure without the need for reference light. In our previous work on SPICA, a coded aperture (CA) was implemented with only amplitude modulation, resulting in a low transmission factor and low light efficiency beca

In this Letter, we present a method for jointly designing a coded aperture and a convolutional neural network for reconstructing an object from a single-shot lensless measurement. The coded aperture and the reconstruction network are connected with a deep learning framework in which the coded aperture is placed as a first convolutional layer. Our co-optimization method was experimentally demonstrated with a fully convolutional network, and its performance was compared to a coded aperture with a

A new technique for space-variant processing with optical array logic and a new concept for parallel processing called pattern logic are proposed. Optical array logic is a technique for achieving any parallel neighborhood operation by simple coding, optical correlation, and parallel OR operation. Using pattern logic, various kinds of parallel processing can be realized, which can be implemented by optical array logic. Several kinds of numerical data processing are presented to verify the capabil