The invention relates to a surface measurement method and a surface measurement device. The surface measurement method includes the steps following steps that: a surface to be measured is provided; the interference fringes of a local region of the surface to be measured are acquired and horizontally enlarged; and the surface height of the surface to be measured is obtained according to the horizontally-enlarged interference fringes of the local region of the surface to be measured. According to the surface measurement method, the local region is measured to characterize an overall condition under a premise that the frequency of the light source of the surface measurement device and the measuring mechanism of the surface measurement device are not changed, the number of measuring points cansatisfy the requirements of the Nyquist frequency of the local region, and therefore, the surface characteristics of a surface with large variations in surface height can be truly and accurately reflected. The surface measurement method can truly and accurately reflect the surface characteristics of a 2D cover plate and a 3D cover plate having large variations in surface height.

Surface measurement method and surface measurement device

The invention discloses an efficient and high-precise re-calibration method for a structural light three-dimensional measurement system. The method comprises the following steps: normalizing various image plane matching image point coordinates and using critical distance as the constraint to perform basic matrix solving, wherein the process can automatically reject the mismatched point or the point containing large error, thereby reducing the influence on the calibration precision by the noise; secondly, solving a scale factor by utilizing space field constraint, and importing feature size constraint or/and space relative distance constraint in a measurement space, and solving the scale factor according to the standard size or/and space relative distance and a measurement value, and endowing weight on the a multi-view measurement system according to each monocular scale factor and performing weighting to obtain a global scale factor, thereby improving the solving precision of the system local parameter and providing precision guarantee for the subsequent three-dimensional information measurement of the measured object.

Efficient and high-precise re-calibration method for structural light three-dimensional measurement system

The invention discloses an optical element surface local gradient surface shape error interference measurement method and device. On the premise that an original interferometer light path is not changed, measurement of a local gradient surface shape error which cannot be measured before is achieved; a double-optical-wedge compensator is placed in a local steepness surface shape error area, and therelative rotation angle of the double-optical-wedge compensator and the overall roll angle around an optical axis are rotated to generate a direction-adjustable additional inclination compensation phase, so that a local measurement light beam is matched with a local surface shape, interference fringes become sparse, and an interferometer is used for measuring the local phase; the introduced phaseis calculated according to the rotation angle of the double-optical-wedge compensator and input into a virtual interferometer model, and calculation is carried out to obtain a local surface shape error; sequentially, the measurement process is carried out on all local parts which cannot be directly measured by the optical element until all local gradient surface shape errors are measured; and splicing is conducted on the local surface shape error and the full-aperture surface shape error data of the optical element to complete measurement.

Optical element surface local gradient surface shape error interference measurement method and device

An inter-satellite laser communication system can be applied to free space laser communication. The principle of the system device is that in an emission light path, after passing through a 45-degreereflecting mirror, intensity modulated laser is emitted out through a receiving and transmitting shared light path. In the receiving optical path, the received signal light firstly passes through thereceiving and transmitting common optical path and then enters the photoelectric detection unit after passing through the optical filter, so that the position calculation and the extraction of communication signals are realized. The receiving and transmitting shared optical path is composed of a front optical wedge, a rear optical wedge, a receiving and transmitting lens and a central hole reflector. The establishment of a laser communication link is realized through the cooperative rotation of the front optical wedge and the rear optical wedge. The receiving and transmitting lens is used forfocusing the received parallel light and collimating and outputting the emitted light. And the mesoporous reflector is mainly used for realizing the separation of light receiving and emitting paths. The system has the characteristics that the design scheme of coaxial receiving and transmitting is adopted, the size is reduced, and meanwhile the stability of the system is improved. And the isolationdegree of the system is increased by using a mode that the emission wavelength is different from the receiving wavelength. And the deviation angle of the light beam reaches +-30 degrees in a mode ofrotating double optical wedges.

Inter-satellite laser communication system

An optical system polarization structure comprises a vertical-cavity surface-emitting laser, a wafer level optics, diffractive optical elements, a polarizing piece, and a 1/4 lambda wave plate, wherein the polarizing piece is arranged between the wafer level optics and the diffractive optical elements, and makes elliptically polarized light pass through a grating of the polarizing piece to form linearly polarized light; and the 1/4 lambda wave plate is arranged between the polarizing piece and the diffractive optical elements, and makes the linearly polarized light pass through the 1/4 lambdawave plate to form circularly polarized light. Therefore, by adopting the polarizing piece and the 1/4 lambda wave plate for polarized light correction, a circular spot of single-wavelength laser is corrected, the shape of the spot is improved to the ideal shape, the calculation accuracy rate of the centroid position is improved, and thus the precision of a depth feedback signal of a dot projectoris improved.

Optical system polarization structure

The invention discloses a light projection device used for the three-dimensional measurement of an object surface. Laser generated by a laser generates polarized light through an optical expansion unit, a mirror and a first polarizing piece. The polarized light is projected to front and back surfaces of a first sensitive optical flat plate, and forms two light paths through the sensitive optical flat plate. The first light path forms vertical polarized light through a second polarizing piece, and the vertical polarized light is projected onto a second sensitive optical flat plate through a first optical wedge pair. The second light path forms vertical polarized light through a third polarizing piece, and the vertical polarized light is projected onto the second sensitive optical flat plate through a second optical wedge pair. Two light paths form combined beam through the second sensitive optical flat plate, and the combined beam is enlarged sequentially through a 1/4 wave piece, an adjustable polarizing piece and a projection objective, and is projected onto the measured object surface. According to the invention, a polarization technology and a phase shift stripe technology are combined; the three-dimensional topography of the surface of various objects of different structures is measured by a machine/off-machine; and the light projection device has strong abilities of vibration resistance and noise dynamic, and especially has strong robustness for the surface measurement of molds with complex structures.

Liao Baijun

Papers

Light projection device used for three-dimensional measurement of object surface