Research On 3D Imaging Simulation Based On 2D Fourier Transform Of Fringe Image

Structured light three-dimensional imaging is a non-contact optical imaging technology,which has the advantages of fast measurement speed,high accuracy and strong robustness.It has been widely used in many fields,such as clinical diagnosis,industrial quality inspection,and the protection and restoration of ancient relics.With the rapid development of society,the application fields of structured light three-dimensional imaging are more and more extensive,the application environment is more and more diverse,and the technical requirements for it are also more and more strict.Among them,the Fourier transform three-dimensional imaging method has the advantages of only projecting a coded fringe pattern to realize three-dimensional surface shape imaging,and has the advantages of fast imaging speed and strong real-time performance,which makes it suitable for dynamic three-dimensional imaging and online three-dimensional imaging and other occasions requiring high real-time performance The Fourier transform three-dimensional imaging method converts the image information from spatial domain to frequency domain by Fourier transform,extracts the first-order spectral components containing the three-dimensional topography information of the measured surface,and then implements the inverse Fourier transform to realize the three-dimensional imaging of the measured surface.At present,the three-dimensional imaging Fourier transform method is generally used positive fringes for three-dimensional imaging,fringe image spectrum of first-order spectrum components and zero order,second order spectrum aliasing,and band-pass filter to extract the first order spectrum component will lose part of their own information or mixed with more other order spectrum component,and when the dramatic changes of the surface height to be tested,the more complex shapes,The more serious the spectrum aliasing phenomenon is,the greater the three-dimensional imaging error is and the worse the three-dimensional imaging effect is,which leads to the poor adaptability of this method to the shape of the measured surface and limits the application of this method.Therefore,this paper mainly studies the following contents:(1)A three-dimensional coordinate measurement model based on fringe images is constructed.Through the analysis of the Spatial ray trace between the image point of projective fringes,the measured point on the surface of the object and the imaging image point on the surface of the camera,establish the mathematical expressions between the three-dimensional coordinates of the object points on the measured surface,the coordinates of the image points on the camera imaging surface and the parameters related to the absolute phase of the fringe image,so as to construct a three-dimensional coordinate measurement model based on the fringe image.(2)A two-dimensional Fourier transform three-dimensional imaging method based on oblique fringe pattern is developed.With the improved project fringe pattern to relieve the fringe frequency spectrum of first-order spectrum components with zero order and second order spectrum aliasing,and through the projection oblique fringe pattern to realize three-dimensional imaging,the method is effective in relieving the spectrum aliasing,improved the measurement accuracy of the measured surface three-dimensional coordinates,to improve the three-dimensional imaging effect and improves the adaptability of measured surface shape.(3)An improved two-dimensional Fourier transform three-dimensional imaging method based on oblique fringe pattern is developed.In the two-dimensional Fourier transform based on oblique fringe pattern on the basis of three-dimensional imaging method by using additional DC projection design measures,further easing inclined fringe image spectrum of first-order spectrum components with zero order spectrum aliasing,and further improve the measured surface space three-dimensional coordinate measurement accuracy and imaging effect,to further improve the adaptability of measured surface shape(4)This paper studies the principle of the phase unwrapping method based on number theory,analyzes the error of the phase unwrapping method,and gives the applicable conditions of the method.(5)A three-dimensional imaging simulation system is built.Three-dimensional imaging simulation experiments were carried out on typical plane,inclined plane with different slopes,spherical surface,relief horse with complex shape but small depth fluctuation and mannequin with complex shape and drastic depth fluctuation.Through the experimental results,the two-dimensional Fourier transform three-dimensional imaging method based on oblique fringe and its improved method are quantitatively evaluated and compared.The effectiveness of the three-dimensional coordinate measurement model based on fringe image is verified by the experimental results.And the two 3D imaging methods are developed can improve the measurement accuracy,improve the 3D imaging effect and improve the adaptability of the measured surface shape.