Research On Geometric Correction And Interactive Techniques Of Smart Projection System

In recent years,with the rapid development of processor chips and optoelectron-ic technologies,smart projection systems have become increasingly popular under the promotion of visual display,artificial intelligence,and human-computer interaction tech-nologies.As a simple display device,the traditional projector has been mainly used in industries such as industry,commerce,education,etc.;While the smart projection sys-tem integrates a more powerful processor chip and an optoelectronic subsystem,plus the functions of perception,communication,and interaction,its application areas greatly ex-ceed the traditional projector's,and quite possible to evolve to a kind of pervasive display device.This dissertation starts from the most critical "visualization" and "interactive"technologies in pervasive display,and studies the geometrical correction and interac-tive technologies of smart projection,including the automatic calibration method of the projection system,static and dynamic projection geometric correction methods,optical sensors based projection geometric correction methods.On the basis of these geometric correction method,several interactive projection applications for the intelligent projec-tion system are explored and developed.This dissertation includes the following contents and contributions:1.A projection system calibration method based on Gray-code structured light is studied.In this method,complementary Gray-coded light sequence is projected on the calibration board,a creative Gray-code extraction and decoding algorithm is proposed,and the corresponding 2D coordinates of the chessboard corners in the projector image plane can be accurately calculated,thereby providing a precise set of 3D-2D correspond-ing.On this basis,the intrinsic and extrinsic parameters of the camera and the projector are achieved.The advanced factor of this method is that it can calibrate the camera and the projector at the same time,and the accuracy of the projector is not affected by the calibration error of the camera,thus it has high reliability and accuracy.2.Under the static projection scenario where the position and orientation relation-ships between the projector and the surface are invariant to each other,the geometric correction method based on the homography between planes is proposed for planar pro-jection,and multiple interactive applications are developed.A viewpoint-related geo-metric correction method for irregular surface projection is also proposed.Through the grid automatic adjustment algorithm and the grid texture mapping algorithm,the observ-er can see a projected image with no distortion at a specified viewpoint position.3.Under the dynamic projection scenario where the position and orientation rela-tionships between the projector,the surface and the observer are variant to each other,a viewpoint-unrelated projection geometric correction method is proposed,which en-ables accurately projecting images onto a moving projection surface,or a moving 3D object's surface.A viewpoint-related geometric correction method based on the relative position and orientation relationship between the projector,the surface and the observer is also proposed,which enables projecting images onto the moving projection surface,generating a special pseudo 3D image,and has a special visual effect and interactivity.4.A projection geometric correction method based on optical sensors is proposed.Aiming at the shortcomings of the vision-based projection geometry correction method,which is complicated to operate and susceptible to environmental factors such as illu-mination,background and visible distance,an automatic geometric correction method based on optical sensors and homography is proposed.The optical sensors distributed at the points of interest are used to capture the structured light pattern sequence pro-jected by the projector and converted to the corresponding coordinates in the projector image plane.Then the homography matrix between the projector image plane and the projection plane is calculated and exploited to geometric correcting and display area maximizing.