RU2522840C1 - Electronic space scanning method - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: electronic space scanning method includes projecting structured laser illumination formed by multiple laser line generators lying at fixed angles relative to each other, detecting said illumination with a matrix photographic recorder which successively captures frames with illumination and without illumination for subsequent background differentiation, transmitting an image of the illumination lines to a computing device and determining, by the computing device, a three-dimensional scene image using a triangulation method. Scanning is carried out by successively turning on one or more structured laser illumination lines.

EFFECT: obtaining a three-dimensional model of a scene portrait.

2 dwg

Description

The invention relates to the field of measuring laser technology and can be used to reproduce three-dimensional images of the scene, determine the geometric parameters of three-dimensional objects and their location.

The closest known for its technical nature and the achieved result is the selected as a prototype method, implemented in a device for controlling the geometry of three-dimensional objects and described in patent WO 99/17076. The method consists in forming a contrast line using an anisotropic light source on the measured surface, registering this line with a stationary photo-recording device and determining the surface topography in the beam plane by the degree of curvature of the line using a digital computing device, the input of which is connected to the output of the photo-recording device. Moreover, in order to measure the entire surface, a flat beam is continuously rotated relative to the measured object with simultaneous measurement of the rotation angle.

The disadvantage of this method is the need to measure the angle of rotation of the beam and the presence of mechanical moving parts, as well as the problem of obtaining reliable information with strong external background illumination.

An analogue is the method of non-contact measurement of three-dimensional objects described in patent 2007127463/28. The specified method of non-contact measurement of three-dimensional objects consists in projecting a bright contrast line using an anisotropic light source onto the measured surface, registering it with a digital photo-recording device, transferring the image of this line to a computing device, determining by the computing device the relief of the measured surface in the beam plane by the amount of line curvature .

In this case, the backlight line is stationary relative to the photo-recording device, and scanning it over all sections of the measured surface is carried out by manual movement of the photo-recording device (together with the beam). Reference lines are also provided that are applied to the base panel, which is stationary relative to the measured object, the images of which are recorded by the photo-recording device together with the section lines and transmitted to the computing device, which, by analyzing the location of the reference lines, combines all measured sections into a single surface.

The disadvantages of the considered method are the manual movement of the scanning device and the problem of obtaining reliable information with strong background illumination.

The main problem to be solved by the invention is the development of a simple and reliable way to obtain a three-dimensional model of a portrait of a scene, eliminating the presence of moving parts and working under any background illumination.

A device that implements a method of electronic scanning of space consists of several laser line generators, a matrix photo-recording device, a spectral filter and a computing device. Laser line generators are located at known rigidly fixed angles relative to each other and relative to the photo-recording device so as to overlap the entire field of view of the photo-recording device, which allows you to get rid of mechanically moving parts.

The block of laser radiation sources and the photo-recording device are rigidly fixed and arranged so that their fields of view overlap as much as possible, and the optical axes lie in the same plane and are either parallel or intersect in the far zone. In the ideal case, they intersect at the center of the operating range, while the distance between the optical centers of the unit and the device, as well as the angles of the axes in the selected coordinate system, are determined during the calibration of the device.

The spectral filter, in the passband of which the radiation of laser line generators falls, serves to reduce the sensitivity of the device to background illumination and is located directly in front of the lens of the photo-recording device.

The essence of the claimed invention consists in projecting a structured laser illumination onto a scanned area (Fig. 1), registering its projection through a spectral filter with a matrix photo-recording device synchronized with a structured laser illumination unit in such a way that every odd frame is taken without illumination, and every even frame with backlighting with one or more lines. Further, the received frames are transmitted to a computing device, which subtracts the previous odd frame from each even frame.

Then, the three coordinates of each point of the highlight lines are determined relative to the selected coordinate system. For example, the use of the triangulation method in the coordinate system shown in figure 2, for the selected point on the highlighted line is carried out according to the following formulas:

$$h=\frac{h_C\tan \left({\beta }_L\right)-h_L\tan \left({\beta }_C+{\alpha }_y\right)}{\tan \left({\beta }_L\right)-\tan \left({\beta }_C+{\alpha }_y\right)}$$

$$S=\frac{h_L-h_C}{\tan \left({\beta }_L\right)-\tan \left({\beta }_C+{\alpha }_y\right)}$$

. $$x_0=S\tan \left({\alpha }_x\right)$$

.

Based on the obtained coordinates, a three-dimensional portrait of the scene is restored, while the resolution in the direction of the backlight line is determined by the resolution of the photo-recording device, and in the orthogonal direction, by the number of laser line generators used. Work in real time can be achieved through the use of high-speed matrix photo-recording devices.

The operation of the system in a wide range of illumination is achieved by three stages of filtering: using a spectral filter that performs spectral selection and reduces the intensity of spectral illumination, opens the shutter of the photo-recording device only for the time the backlight is turned on, which provides temporary selection, and subtracts the frame without backlight from the backlit frame (differentiation background).

Claims (1)

A method of electronically scanning space to obtain a three-dimensional model of a portrait of a scene, which consists in projecting a structured laser illumination generated using several laser line generators located at fixed angles relative to each other, registering it using a matrix photo-recording device that sequentially shoots frames with and without backlight for the subsequent differentiation of the background, the transfer of the image of the backlight lines to the computing device and ELENITE computing device voxel scene triangulation method, while the scanning by repeatedly alternately turning on one or more lines of structured laser illumination.

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