Study On Autonomous Perception And Multi-projection Correction Technology Of Estimable Surfaces

The multi-channel projection technology and systems can realize high-resolution,highimmersed,the real-time realistic rendering and display of large-scale and complex scene,it can also create the novel and unique effects of the visual display.It has a huge application foreground in the fields of commercial,military,scientific research and so on.The projector only has the capability of projection display but can't percept the projection scenes,which is unable to adjust the projection image by itself.Therefore,projectors are just designed for the conventional surfaces(white texture,ideal plane)in currently.The projectors will be affected by many factors(such as the texture color,the surface fluctuations irregularity…),when they are applied in a specific complex unconventional display environment,which can make the projection screen generate serious visual interference to viewers.So that the geometry and color consistency correction of multi-channel projection image under unusual projection surface conditions is more complicated,compared with the conventional display surface of plane,which is the important challenge and issue in the development of projection display technique.In order to realize the fast and high-precision perceptive reconstruction of the free-form surface and the autonomous correction of the multi-projection of the unconventional projection surface,so that it can adapt to different scene environments and carry out the projection visual display.This paper makes an exploratory analysis to the imaging mechanism of the projector's camera vision system and relevant theoretical methods of multi-projection technology,launches a further research on autonomous perception and multi-projection correction technology of estimable surfaces and innovatively proposes some new methods and new ideas combined with the existing problems of relevant methods,the main work and innovation of this paper include:(1)In the process of 3D reconstruction for structured light,the complexity of the environment light source and the nonlinearity of projector and camera and other factors will have an effect on the decoding of structured light.In order to reduce the influence of factors mentioned above and improve the precision and efficiency of structured light decoding,a highprecision decoding method of color-coded structure light was proposed.Firstly,the modulated image captured by camera was converted into the YUV color space,and the edge extraction algorithm of the filtered differential projection under the YC channel was proposed to realize the edge localization of the modulated stripe.Then the central characteristic line of the modulated stripe was acquired by using the sub-pixel extraction method of center stripe based on the waveform decision guidance.Considering the low precision of color identification of the modulation stripe caused by the reflectivity of the test surface and the environment of scenes,the clustering identification algorithm of the modulation stripe color code was adopted to obtain the values of color code information of the central feature line.The experimental results show that this method has strong anti-interference and robustness.(2)The color information of the color-coded stripe will be absorbed and reflected when the surface texture color of the object under test is deep,which makes serious discrepancy between the information of the color code collected by camera and the information of the original color code,thereby appearing the misjudgment phenomenon of color in the decoding process,which results in the identification errors of color code and the matching errors.Therefore,the 3D reconstruction method of multi-source hierarchical sequential projection color object was proposed.Using the characteristic that of black and white stripes' low degree of interference to the texture color,carried on the multi-source hierarchical dispose of black and white stripes to color-code stripe images.During the decoding,extracting the central characteristic line of hierarchical sequential projection stripes to determine the values of colorcode information of modulation fringes.Finally,the matching method of stripe codeword based on repeatability of sequence characteristic was proposed to match the color codes of modulation stripes and the code stripes of original projection.The experimental results show that this method can not only effectively solve the problem of texture interference of surface under test,but also reduce the influence of environmental factors and system hardware factors on decoding.(3)Because the non-regular curved surface will cause the projection display to stretch and distort nonlinearly,it's difficult to realize the high-precision correction,which restricts the flexibility of the use of the projection equipments.Non-regular projection surface adaptive correction method was proposed.Focusing on the issues of low precision of corner recognition and poor anti-noise during parameters calibration of the projector's camera system,a sub-pixel detection algorithm of corner points was proposed.And in the solving process of system calibration parameters,an imaging-feedback projective geometric constraint optimization method was proposed,which can improve the accuracy of the system parameter calibration.Then an autonomous projection correction algorithm based on the analysis of topological structure was proposed,which can effectively solve the problem of the projection geometric correction on the surfaces of complex projection.Through experimental analysis,it can be seen that the degrees of surface parallelism and line perpendicularity are high when the calibration accuracy of the system parameters reaches to 0.25 pixel.Meanwhile the problem of the universal display of the single-projection display technology under the unconventional projection environment is effectively solved,so that the observers are able to perceive similar visual perception as in the plane projection display environment and understand the contents of the projected image.(4)In order to solve the problems of geometric distortions of the multi-projection display images and the uneven brightness and color deviation of the display images on the conventional projection display surfaces,geometric consistency correction and photometric consistency correction of multi-projection display images were proposed and implemented.This method doesn't need to man-made adjust the posture of system hardware too much,which will simplify the process of installation and adjustment of multi-projection display system and realize a fast and autonomous multi-projection display effect.For the irregular deformation of the multi-projection display generated by non-standard free-form surface and interference problem of the projection visual effect images produced by texture color,a multi-projection self-perception correction algorithm of non-standard free-form surface and a color compensation and correction algorithm based on decision guided sheet spline interpolation were proposed.From the analysis of experiment,it can be seen that this method can effectively reduce the interference of multi-projection display images generated by non-standard freeform surface and improve the observers' visual perception degree of projection images and comprehension degree of contents.And the application range of the multi-projection display technology is also expanded.(5)Aiming at the mutual light scattering effect between adjacent projection screens that immersive multi-projection system faces,which causes the differences problems in color and brightness emerging on projection screens.Through the deep analysis for the mathematical model of mutual scattering effect between multiple projection screens,a light scattering compensation algorithm of immersive multi-projection system was proposed,while a set of immersive multi-projection display system platform was established.Through analysis of experiment,it can be known that the immersive multi-projection display system constructed in this paper not only effectively solves the problem of mutual light scattering under the mode of back projection,but also implements the highly immersive multi-channel projection seamless splicing fusion consistent display.The study of this paper can promote the multi-projection display technology to develop rapidly towards the direction of intelligence,practicability and efficiency.