We present a new approach for computer-generated integral photography (IP) based on ray tracing, for the reconstruction of high quality photorealistic 3-D images of increased complexity. With the proposed methodology, all the optical elements of a single-stage IP capturing setup are physically modeled for the production of real and virtual orthoscopic IP images with depth control. This approach is straightforward for translating a computer-generated 3-D scene to an IP image, and constitutes a robust methodology for developing modules that can be easily integrated in existing ray tracers. An extension of this technique enables the generation of photorealistic 3-D videos [integral videography (IV)] and provides an invaluable tool for the development of 3-D video processing algorithms.
A miniaturized laser-scanning endoscope is presented that makes use of a composite laser beam for color imaging. A novel approach is followed in the device, which is based on scanning the target tissue with the laser beam using two miniaturized MEMS (microelectromechanical systems) micromirrors and employs specific collection, detection, and postprocessing of the scattered light for reconstructing a color image of the tissue. A resolution of the order of 16 line pairs/mm is achieved for a working distance of 50 mm while the focal depth is larger than 5 mm. Key considerations of the system design are presented, along with results on the operation of the micromirrors, an analysis of the optical design of the endoscope head, and remarks on the assessment of image quality.
One of the most promising techniques for visualizing three-dimensional objects is Integral Photography (IP). Two common methods used in synthetic IP generation involve the development of simplified raytracing algorithms for elementary 3D objects or the realization of pinhole arrays. We present a technique utilizing POVRAY’s raytracing capabilities to generate synthetic, high-quality and photorealistic integral images, by accurately modeling an actual microlens array along with the necessary optics. Our work constitutes a straightforward approach for translating a computer generated 3D model to an IP image and a robust method to develop modules that can be easily integrated in existing raytracers. The proposed technique simulates the procedure of a single stage IP capture, for producing a real orthoscopic IP image. Full control is provided over geometry selection, size and refractive index of the elementary microlenses. Specifically our efforts have been focused on the development of arrays with different geometries (square or hexagonal) in order to demonstrate the parameterization capabilities of the proposed IP setup. Moreover detailed benchmarking is provided over a variety of sizes and geometries of microlens arrays.
A miniaturized laser scanning endoscope is presented which makes use of three lasers to illuminate a sample with a red, a green and a blue wavelength simultaneously. Scattered light from the sample is descanned and chromatically separated into the three channels for detection and postprocessing to compose a color image. The scanning subsystem consists of two micro-electro-mechanical mirrors suitable for mass production. The endoscope head can be assembled fast and at low cost. A resolution of the order of 16 lines per mm is achieved for a working distance common in endoscopy. Considerations of the system design include the operation of the mico mirrors, the filtering of reflected light by using polarization effects and a strategy to cope with color metamery. An expert system based on a neural network was found able to analyze endoscopic images to identify suspicious lesions.
Contemporary methods for minimally invasive interventions are gaining wide acceptance in various everyday operations, offering extremely localized treatment, reduced suffering and practically no risk for the patient as well as great benefits to diagnostic examinations and surgeries that require continuous monitoring. Many established endoscope systems offer the aforementioned advantages without the risks and restrictions of the computer-aided tomography techniques but with limitations in the resolution and chromatic representation provided. A microscanning specific-endoscope device has been developed aiming to provide superior resolution and chromatic representation in comparison with the above endoscopes. The key technology employed in the design of this endoscope relies on the use of tiny microelectro-mechanical silicon mirrors for the scanning of three laser beams over the target tissue area. The so-developed microscanning endoscope system provides color imaging with high resolution at near video rates targeting at macroendoscopy applications. The optical design and implementation of this endoscope system will be presented in this communication together with a brief description of the overall endoscope device developed. In addition results are given from the study of the metamery effect that is utilized in the realized endoscope, together with a presentation of the procedure followed for the objective evaluation of its optical performance and first results from system operation.