In this paper, we try to present an improved effective segmentation algorithm for range images. Our work was
partially motivated by the desire to overcome the drawbacks inherent to most of the algorithms known from the literature,
which edge detection is mostly criticized for its tendency to produce non-connected boundaries and region-based
techniques suffer from a number of problems, such as complex control structures, the selection of initial regions, the
actual number of clusters and an over segmentation. It provides edge strength measures that have a straightforward
geometric interpretation and supports a classification of edge points into several subtypes. We consider analysis of
geometric properties of edge points as the key to solve the problem of image segmentation and propose a geometric
model to deduce algorithm template. And we adopt morphological method to boundaries obtained in the edge map as to
save much time. Experiments were performed in a popular range image database and the results were compared to five
other traditional range image segmentation algorithms, demonstrating that it could achieve more edge information of the
object and overcome the shortcoming of non-connected boundaries to a certain extent. It is proved to be correct and
effective.
KEYWORDS: Computer programming, Image processing, Projection systems, Cameras, Commercial off the shelf technology, Digital cameras, Digital imaging, 3D image processing, Machine vision, Structured light
The goal of structured light techniques is to measure the shape of three-dimensional object using automatic non-contact techniques and based on trigonometry measurement. This thesis deals with the device of obtaining range image based on multi-line structured light. The projector is taken as the projecting source of this device and can project multi-line structured light. The digital camera is taken to obtain stripe image and can capture the stripe image in a single frame. The technique of space encoding is utilized to process the stripe image and could avoid the aliasing of the multi-line structured light. This technique can ensure the veracity of the range image obtaining. The experiments have shown that the range image obtained by this device have better results and higher speed of acquisition. Measuring range of this device is 200mm(X)×120.0mm(Y)×150.0mm(Z). The measuring error of Y and Z direction is less than 0.3mm. The measuring error of X direction is less than 0.1mm.The absolute error of the measurement result in the direction of Z is less than 0.2%.
In this paper, the vision sensor is made up of four laser devices (LD) and four cameras. Standard difference value contrast method of calibration is put forward. The whole system’s parameter calibration is consisted by four sub-system’s calibration independently. Special target probe moves in standard grid mode in the measured two-dimensional plane. Gray-level centroid method is used to acquire four groups standard grid node. From the difference of standard grid node the segment linear calibration equations are obtained. The whole measured section is divided as grid block by every adjacent group standard mean coordinate values Z and Y. In the grid block all the measured coordinate values are calibrated by segment linear equations along Z and Y axis direction. The whole system is calibrated only by getting data once. The system calibration result shows the system measurement errors is less than 0.2 mm within 100 mm depth measurement.
The opto-contact mini-displacement measuring instrument is mainly for mini-displacement measurement. It not only can measure small geometry size, for example silicon chip thickness, but also can measure some other parameters such as small translation, waviness, diameter run-out, vibration. Combining optical, mechanical, electronic and computer technologies, this instrument can do some work automatically like dynamic sampling, real-time processing, on-line measuring. The instrument is based on laser triangulation, it is composed of a CCD, an optical system and a computer, which can sample and process data with high speed. The measuring principle is described as follows: reflected or scattered light by measured surface are received by CCD, since a good relationship between the offset of image point on CCD and the mini-displacement of object located on a reference plane, a mathematical model can be founded, then the mini-displacement may be calculated according to the offset of image point position on CCD. It's measuring range is +/- 500 micrometers , and precision resolution is +/- 0.1 micrometers .
In this paper, simultaneous frequency, power and beam direction stabilization of transverse Zeeman Laser is reported. The axial mode of He-Ne laser is collapsed into two polarized components perpendicular to each other in a transverse imagination field. By setting up a proper thermal field, taking a frequency difference, between the two composts as the stabilization parameter, the output angle floating is less than 2 X 10-4, the relative power stability of 0.089% and the qencystability of 4 X 10-10 is obtained.
In our profiler, software is the key-point. During the course of reference height of each point of the surface by computation and comparison of modulation M and so we can get surface profile. In the course of computation and comparison of modulation M, the ability of software will decide whether our profiler can be applied into practice. In this paper, we did some research work in software, and provided three- frame, five-frame and digited filer processing ways.
This paper describes a kind of profiler with the above features. It uses the white-light interfering method and adopts the structure of Micelson interferometer. It includes the light bulb used as the light resource, CCD used as the sensor, PZT providing microscopic translating and the computer sampling and processing data with high speed. When the reference-mirror translating, computing and comparing the modulation M of each point of the surface will give their relative surface height. Then we obtain the surface profile of object to be measured.
This paper describes a laser scanning range finder that may produce a real time space encoding pattern. Laser diode is modulated by a programmable controller. So a space encoding sequential constructive laser beam is employed as an active illuminating source. Using less frames of space encoding patterns to produce a range image with high resolution is the main goal of this study. The calculation of 3D coordinates of each point on the measured object is explained briefly.
A method based on continuously modulating the vapor deposition angle, δ, in the range from
0° < δ < 180° at an appropriate rate is proposed, by which the typical colunmar structure of vapordeposited
thin films can be prevented in favor of a more compact structure, similar to a bulk
material. The growth rates of such films are quantifed, and the their microstructure is simulated by
computer. At the same time, an experimental study has been performed successfully. Lastly, the
mechanism underlying these improved properties is analyzed and discussed.
The cylindrical model of optical thin films microstructure is assumed for the derivation of the
equations expressing the structure-dependent anisotropic optical parameters in this paper. The
equations are given for various values of cylinder obliquity and for several incident plane
orientations. The equations are based on a capacitive model in which two index components are
given and on the dielectric ellipsoid theory. They are applied to modeling ZnS thin films and the
computed results have been given. We discuss the results, especially noting consistency of our
model-based computations with measurements.
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