New definitions will help pavement cracking survey providers and pavement engineers at state highway administrations conduct objective cracking measurements and encourage continuing technological innovations by researchers and vendors.
The TRB National Cooperative Highway Research Program's NCHRP Web-Only Document 288: Standard Definitions for Common Types of Pavement Cracking helps develop standard, discrete definitions for common cracking types for asphalt and concrete pavements.
3DSurvey 2020 Crack
Reference:Malin Waage, Pavel Serov, Karin Andreassen, Kate A. Waghorn, Stefan Bünz. Geological controls of giant crater development on the Arctic seafloor. Scientific Reports, 2020; 10 (1) DOI: 10.1038/s41598-020-65018-9
"It turns out that this area has a very old fault system -- essentially cracks in bedrock that likely formed 250 million years ago. Craters and mounds appear along different fault structures in this system. These structures control the size, placement, and shape of the craters. The methane that is leaking through the seafloor originates from these deep structures and is coming up through these cracks." according to Malin Waage, a postdoc at CAGE, Centre for Arctic Gas Hydrate, Environment and Climate, and the first author of the study.
This study aimed at evaluating the feasibility of combined images and LiDAR data for façade features detection and measurement. In particular the 3D representation of the crack propagation and geometrical formation. The approach acquires LiDAR data and 2D images independently, the images collected at optimal position and time for capturing the surface details. The transformation of 3D LiDAR point clouds to 2D structured depth images enables the implementation of existing computer vision algorithms developed for 2D color images. The depth map will be produced for every 2D image, resulting in an additional D-channel to the color (RGB) image channels. The algorithm is implemented on experimental data collected from the Treasury of Petra Ancient city in Jordan.
Although a large number of surface points and triangles are identified in the 3D model created by the laser scanner, outlines such as edges and cracks are lost beyond the resolution of the available laser information. Modeling these features can further reduce data sizes, allowing for advanced analysis of simplified models instead of bulkier point clouds. While many current cloud segmentation approaches have been shown to effectively segment TLS data, complex real-scene implementations still have significant shortcomings and challenges. Existing methods of segmentation require curvature and normal estimation before data analysis and grouping. Despite a number of solutions to adaptive neighborhood description, curvatures approximation on edges or rough surfaces such as the historic building can still be unreliable [40]. In order to clarify this problem in our data, we apply a mean curvature segmentation algorithm proposed by Alshawabkeh et al. [41]. The proposed algorithm efficiently estimate the mean curvature value at each sampled pixel using convolution distinct sizes of windows running across the image in only one direction. The algorithm classifies the edge points based on selected threshold values of the mean curvature. Using multiple-scale masks allows for reliability in estimating curvature values in the presence of noise problems, particularly in real scene environments. The findings of the experiment are shown in Fig. 4. Various mask sizes and threshold values are used, but the small surface features are still missing, the clear edges are only detected.
The integration of photogrammetric and LiDAR data has shown a significant promise in extracting the surface features from dense 3D point cloud data on the real scene façade. In heritage applications, automatic detection of the continuous extent of material displacements with digital measurements will reduce cost of field inspections and increase safety. The presented algorithm utilizes the intensity values of the color images with the LiDAR data to automatically detect and quantify façade linear features. Given an unstructured point cloud as input, a structured depth channel is sampled and projected to the color channels to compute (RGBD) layers. The linear features of the surface are initially extracted using the optical 2D imagery and subsequently, each pixel of the linear features is projected directly into 3D space. The proposed solution is flexible as it acquires point clouds and images separately, allowing the high visual quality of the scene features to be optimized in time and place. Experimental results from real data are used to evaluate the performance of the proposed methodology. The approach robustly defines façade features and provides better interpretation of spatial growth of weathering forms and severe cracks. Additionally, modeling these features significantly reduces the amount of data that can be viewed and fluently interact in 3D, allowing for surface analysis with simpler models. It is expected that the extracted features can be used in future researches to evaluate and monitor the architectural buildings structure. Although the current version of C++ algorithms does not yet run in real time, during improved application it is expected to be implemented in real time.
The bridge has been checked for the presence of bats by using an endoscope (a small camera on the end of a flexible cable) to check cracks and crevices. Ecologists also undertook dawn and dusk surveys where they used specialised listening equipment to identify any bat species arriving or leaving roosts within the bridge. This identified a possible emergence by a soprano pipistrelle. All bat species are protected under UK law, so precautionary measures are being put in place to mitigate the risk of disturbing bats or damaging their habitat.
Our crack team is working day and night to increase the accuracy of the software. Our professional development team is still busy seeing the machine and also processing the accuracy of the image and final output of the product.
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