In this paper, we propose a new design of an imaging optical system combining the advantages of stereoscopy and spectroscopy principles. The quality of spectral stereoscopic image is the key factor influencing the accuracy of threedimensional (3D) measurements and shape reconstruction. The main advantages of acousto-optical tunable filters (AOTF) in combination with stereoscopic imager are shown. We developed a new scheme of an imaging AOTF-based stereospectrometer in order to raise accuracy of 3D-measurements. According to numerical simulation, the scheme has improved image quality compared with existing ones.
We consider the problem of 3D imaging spectroscopy on base of a pair of acousto-optical tunable filters (AOTFs). In such a system, quality of stereoscopic spectral images is the key factor influencing the accuracy of three-dimensional (3D) measurements and shape reconstruction. We analyze the image quality in a dual-channel AOTF-based spectrometer and proposed the optical scheme, which is free of image blur and has only aberrations of image distortion and drift. They can be eliminated by means of geometrical calibration of the imager. The optical characteristics of the system prototype are presented. The theoretical analyses and calculations of image aberrations are confirmed by experiments. The devices based on the dual-channel AOTF-based stereoscopic system may be effectively used for various 3D imaging spectroscopy applications.
Nowadays, the stereoscopic endoscopy is a widely used tool for precise three-dimensional (3D) measurements of hard-to-reach elements in industrial and biomedical applications. The most common approach for its implementation is the utilization of prism-based optical tips which allow to acquire two images from different viewpoints on a single sensor. Stereo video endoscopes are typically equipped with a wideband white light source, but contrast visualization of the inspected object and, therefore, accurate quantitative characterization of its parameters often requires narrow band spectral imaging. We show that the standard geometrical calibration may lead to significant measurement errors when obtained using white illumination and applied to narrow band images. In order to overcome this, we propose the new calibration procedure based on a proper choice of a few spectral bands for calibration and interpolation of the calculated parameters. Results of multiple experiments show that the proposed technique fosters the measurement accuracy increase.