Research And Application Of Stereo 3D Reconstruction Technology For Light Field With Single Lens

3D reconstruction refers to obtaining the 3D information of the scene,so as to construct the stereoscopic scene in the computer.Traditional camera shooting can only obtain 2D information of the scene,but cannot obtain depth information,so obtaining depth information becomes the key to 3D reconstruction.Traditional cameras acquire depth information through multi-camera acquisition,single-camera multi-view acquisition,and active depth detection.The light field imaging technology can realize the single-lens acquisition system to acquire depth information at one time.Therefore,the stereoscopic 3D reconstruction of a single lens can be realized by using light field imaging technology.Light field imaging technology mainly includes two parts: light field acquisition system and post-processing calculation.The current mainstream light field acquisition system has a single optical aperture,and functions such as digital refocusing and depth estimation can be realized through post-calculation processing.Thesis will start from the basic principle of light field,design and implement a single-lens low-light light field acquisition system,and study the light field depth estimation algorithm to realize the stereoscopic 3D reconstruction of a single lens.The main research contents are as follows:(1)The design has implemented a single-lens low-light light field acquisition system.In order to expand the depth of field of the low-light imaging system and explore the three-dimensional reconstruction of the light field in low-light scenes,a small F-number low-light light field camera based on a microlens array was designed and manufactured.The original light field data was pre-processed to achieve low-light light field data acquisition.(2)A light field depth estimation algorithm is proposed based on the gradient symmetry of the focus stack.A high-quality sequence of focal stack images is obtained using the phase shift theorem;through mathematical derivation,it is verified that the image gradient of the refocused image in the focus stack is symmetric before and after full focus;it is constructed using the gradient symmetry of the focus stack and the subaperture image difference The cost function is used to complete the depth estimation.3D reconstruction is achieved using the depth estimation results.(3)Experiments such as low-light refocusing and depth-of-field expansion were carried out in the low-light light field acquisition system,demonstrating and proving the light field detection capabilities of the acquisition system;3D reconstruction experiments were carried out using the acquisition system and Lytro Illum cameras,and the different data were demonstrated.The 3D reconstruction results verify the effectiveness of the 3D reconstruction method in thesis;finally,the algorithm of thesis is verified by using the data with real depth.The objective indicators and visualization results show that the algorithm in thesis has better depth estimation results;the results in special scenes show that the algorithm has better robustness to camera noise.