A rapid development and growing popularity of additive manufacturing technology leads to new challenging tasks allowing not only a reliable monitoring of the progress of the 3D printing process but also the quality of the printed objects. The automatic objective assessment of the surface quality of the 3D printed objects proposed in the paper, which is based on the analysis of depth maps, allows for determining the quality of surfaces during printing for the devices equipped with the built-in 3D scanners. In the case of detected low quality, some corrections can be made or the printing process may be aborted to save the filament, time and energy. The application of the entropy analysis of the 3D scans allows evaluating the surface regularity independently on the color of the filament in contrast to many other possible methods based on the analysis of visible light images. The results obtained using the proposed approach are encouraging and further combination of the proposed approach with camera-based methods might be possible as well.
One of the results of the dynamic progress in the field of industrial and applied computer science and mechatronics is the growing interest in usage of the machine vision algorithms and systems. One of such areas of applications is the positioning of the workpieces on the CNC machines based on the image analysis, allowing also the visualization of the workpiece observed from an arbitrary viewpoint located between two or more cameras. Such virtual camera can be effectively implemented using Image Based Rendering technology [ but one of its limitations is the necessity of using the depth maps, which have to be acquired for each reference image. It can be done using the additional fringe patterns projector, similarly as in typical 3D scanning systems or using some other approaches e.g. stereovision. Nevertheless, the quality of images obtained using the typical IBR method is limited by the missing pixels (holes), which should be filled using splatting algorithm, which typically cause the noticeable blurring of obtained image. The solution proposed and discussed in this paper is based on the sub-pixel IBR method with additional filtering and interpolation of the points acquired from the reference cameras allowing increasing the quality of the final images obtained as the visualization of the positioned workpieces.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.