The Technology Of 3D Measurement Based On Multiple Spectral Bands And Spatial Light Modulation

The 3D profile measurement technology has widely application and promising future in fields of industrial online inspection, robotic vision, biomedicine etc. The opti-electronical 3D profile measurement has obtained attention widely due to the advantages of high speed, high precision, automatic measuring and non-contact. The opti-electronical 3D profile measurement that has the characteristics of big area, high speed and precision is researched deeply. Aiming at the technique difficult in opti-electronical 3D measurement, the paper presents the theory of the multi-spectral bands color separate and spatial light modulation based on virtual grating and projection. The methods of phase synthesis and measurement based on multiple images are analyzed and the experiment research results are given.In the paper, aiming at demands and application of the technology the chapter one compares the touch and the untouch measurement method of the 3D profile measurements. The chapter studies on the principles and characteristics of the opti-electronical profile measurement by the development of the modern measurement technology. The research and development status of the popular technology in optical 3D profile measurement are expatiated in this chapter. Then the paper analyzes the key techniques of opti-electronical 3D profile measurement. In the second chapter the paper analyzes the measurement course and builds a commonly model on spatial light modulation by projection. The effect on optical configuration, selection of modulation direction, spatial sampling characteristic of plane CCD image sensor and the aperture of the optical system are analyzed in opti-electronic 3D profile measurement of projection and optical modulation. The chapter three discusses the methods to produce the cosine virtual spatial modulation fields firstly. Then the cosine specialty of these spatial modulation fields is studied by experiments. In the chapter four, aiming at the difficulty in existing optical 3D profile measurement the paper presents a theory of the multiple spectral bands modulation and color separating based on the analysis of color description system about digital image and chromatic theory. The technology of color separating intensity modulation realized three kinds of spatial frequency modulation in a frame of digital image by color channel separating in RGB color system. And the feasibility of the spatial hue modulation is studied in the chapter according to the analysis on HSV color system. The technology of spatial continuous hue modulation is presented. Finally the experiments of the multiple spectral bands modulation are given. In the fifth chapter, the paper analyzes the spectrum characteristic of the distorted grating image in the spatial intensity and hue modulation by single frequency. The effect on phase measurement by discrete Fourier transform image process is studied. The chapter gives the precision analysis and experiment result of the single spatial frequency modulation. In the chapter six, the paper presents a phase synthesize measurement method of parallel and perpendicular double spatial frequency modulation to resolve the problem of phase unwrapping difficulty using Fourier transform in the single frequency modulation. The chapter analyzes the effect of these methods to the precision of 3D measurement and gives the experiment result adopting the color separating intensity modulation. In the seventh chapter the principle of spatial phase shifting measurement using multiple modulation images is discussed. The chapter studies the factors that affect the phase shifting measurement and presents the technology thar three span phase-shifting by one time record based on the multiple spectral bands intensity modution. Then the paper presents a phase measurement method of spatial frequency shifting based on multiple spectral bands.The experiment result of these techniques are given. Finally the chapter eight summarizes all the paper and prospects the future trend of the optic-electronical 3D measurement based on spatial light modulation.