https://shura.shu.ac.uk/7180/1/Rodriggues_%2D_optical_techniques_%2D_Review_MIA_revision_v9.pdf

Optical techniques for 3D surface reconstruction in computer-assisted laparoscopic surgery.

Dual-modality endoscopic probe for tissue surface shape reconstruction and hyperspectral imaging enabled by deep neural networks.

A miniaturized three-dimensional endoscopic imaging system is presented The system consists of two imaging channels that can be used to obtain an image from an object of interest and to project a structured light onto the imaged object to measure the surface topology The structured light was generated with a collimated monochromatic light source and a holographic binary phase grating The imaging and projection channels were calibrated by use of a modified pinhole camera The surface profile was extracted by use of triangulation between the projected feature points and the two channels of the endoscope The imaging system was evaluated in three-dimensional measurements of several objects with known geometries The results show that surface profiles of the objects with different surfaces and dimensions can be obtained at high accuracy The in vivo measurements at tissue sites of human skin and an oral cavity demonstrated the potential of the technique for clinical applications

Miniaturized three-dimensional endoscopic imaging system based on active stereovision.

This study aims to develop a novel imaging technique to improve the accuracy of the colposcolpic diagnosis of cervical cancer. An optical imaging system based on active stereo vision is built to measure the 3-D surface topology of cervix and track the motion of patient. The information of motion tracking are used to register the time-sequenced images of cervix recorded over the period of examination. The imaging system is evaluated by tracking the movements of cervix models. The results show that the error of 2-D image registration is 0.8 pixels, equivalent to the motion tracking error of 0.05 mm in the field-of-view. The imaging technique holds the promise to enable quantitative mapping of the acetowhitening kinetics over cervical surface for more accurate diagnosis of cervical cancer.

Optical imaging for medical diagnosis based on active stereo vision and motion tracking.

A new system for high speed and continuous 3-D measurement is presented. It is based on the slit-ray projection method. Remarkable features of the system-high speed and continuous measurement-mainly result from its image plane constructed by a PSD array which is horizontally non-divided and linear, but vertically divided in numbers. All row PSD elements are attached to respective analog signal processors; analog signals are digitized through A/D converters and stored in memory elements in order. By the virtue of this image plane configuration basic data for 3-D measurement are acquired during only one scanning of the slit-ray at high speed in the form of addresses of the memory elements and data stored in them. Moreover, using large capacity and/or dual port memories, one may continuously obtain 3-D range data of as many scenes as one wants. A trial system has been implemented using a newly designed PSD array of 128 channels and it has verified the method, obtaining 3-D range data at video rates continuously in an accuracy within +or-0.3%. >

High speed and continuous 3-D measurement system

In endoscope observation, acquiring shape information of a lesion area is highly demanded for objective and statistical judgment. For in-vivo applications, a high-speed measurement is also considerable. Therefore, we proposed an electronic endoscope system that equips an image fiber and a laser scanner, and achieves the high-speed measurement by using the space-encoding method with laser-scanning. In our experiment, the measurement error was 1/spl sim/2% of the distance from the endoscope tip. Moreover the acquired shape information shows that can assist physician for understanding the surface topology of lesion and would be effective in Computer Aided Diagnosis.

Electronic endoscope system for shape measurement

A system based on slit-ray projection method is presented that uses a nonscanning type image plane. It consists of a 2-D array of discrete photodetectors, attached to an individual memory element. The whole system is designed to latch positional information of a slit-ray into the memory when the corresponding photodetector is triggered by slitlike image passing across the image plane. Basic data for range computation are acquired during only one scanning of slit-ray. Trial implementation of this system has verified the method to be effective, showing data acquisition time within a few milliseconds. >

A method for high speed 3-D range measurement and its trail instrumentation

A method of constructing a 3D model of human face by integrating multiple range images that were measured at different view directions is presented. The images were obtained by a high-speed rangefinder system which is capable of measuring the frontal face and capturing a texture image in approximately one second. A complete face model construction is thus performed by measuring the face in different orientations and integrating corresponding range maps using a least squares estimator. Range image integration is carried out in two ways: 1) by direct application of the least squares estimator to range values, and 2) by applying it to corresponding texture index values. A Sobel filter is applied to the intensity images to extract feature boundaries for the estimator. Both methods proved to have high accuracy returns and the average error of integration was estimated to be below 1.3 min.

3D face modeling with multiple range images

A vision system is proposed that has two differentiated visual fields, i.e. peripheral and central, and the fixation point to the scene is actuated actively. The proposed vision system is aiming at an active vision system that recognizes environment actively by gazing at each object of interest. To build this system, the authors developed a vision system with two CCD cameras of which fixation points are controlled by a computer. A fundamental vision model is proposed that consists of five independent neural network modules. Each module is educated individually and processes visual information independently. To signify the feasibility of the proposed vision model, some fundamental experiments were carried out. >

Y. Sato

Papers

Electronic endoscope system for shape measurement

A method for high speed 3-D range measurement and its trail instrumentation

3D face modeling with multiple range images

Active vision with two differentiated visual fields