Maize Plant Phenotyping: Comparing 3D Laser Scanning, Multi-View Stereo Reconstruction, and 3D Digitizing Estimates

High-throughput phenotyping technologies have become an increasingly important topic of crop science in recent years. Various sensors and data acquisition approaches have been applied to acquire the phenotyping traits. It is quite confusing for crop phenotyping researchers to determine an appropriate way for their application. In this study, three representative three-dimensional (3D) data acquisition approaches, including 3D laser scanning, multi-view stereo (MVS) reconstruction, and 3D digitizing, were evaluated for maize plant phenotyping in multi growth stages. Phenotyping traits accuracy, post-processing difficulty, device cost, data acquisition efficiency, and automation were considered during the evaluation process. 3D scanning provided satisfactory point clouds for medium and high maize plants with acceptable efficiency, while the results were not satisfactory for small maize plants. The equipment used in 3D scanning is expensive, but is highly automatic. MVS reconstruction provided satisfactory point clouds for small and medium plants, and point deviations were observed in upper parts of higher plants. MVS data acquisition, using low-cost cameras, exhibited the highest efficiency among the three evaluated approaches. The one-by-one pipeline data acquisition pattern allows the use of MVS high-throughput in further phenotyping platforms. Undoubtedly, enhancement of point cloud processing technologies is required to improve the extracted phenotyping traits accuracy for both 3D scanning and MVS reconstruction. Finally, 3D digitizing was time-consuming and labor intensive. However, it does not depend on any post-processing algorithms to extract phenotyping parameters and reliable phenotyping traits could be derived. The promising accuracy of 3D digitizing is a better verification choice for other 3D phenotyping approaches. Our study provides clear reference about phenotyping data acquisition of maize plants, especially for the affordable and portable field phenotyping platforms to be developed.

3D DIGITIZATION OF FEATURELESS DENTAL MODELS USING CLOSE RANGE PHOTOGRAMMETRY AIDED BY NOISE BASED PATTERNS

Development and improvement of 3D digitizing systems provide for the ability to digitize a growing number of materials and geometrical forms of greater complexity. This paper presents the application of 3D digitizing system using close range photogrammetry on the upper jaw cast in plaster in order to obtain its 3D model. Because of the low visual characteristics of gypsum, such as color and texture, many questions arise about the possibility of applying this particular method to this type of physical models. In order to overcome bad visual properties of gypsum, this paper analyzes the possibility of the photogrammetry method application supported by the projected light texture which is based on patterns in the form of noise-obtained mathematically modeled functions. In order to determine the selected image for light texture which gives the better results, an experiment was designed and carried out. Only two images were tested. One image is selected based on previous research and the other one was generated by the Matlab function for uniformly distributed random numbers. For validation and a comparative analysis of the results, an object of 3D digitization was generated with and without projected light texture. CAD inspection was applied for the analysis of the obtained 3D digitizing results. 3D model obtained by approved professional optical 3D scanner as a reference was used. The results in this paper confirm better accuracy of 3D models obtained with the use of light textures, but this approach requires additional hardware and setup adjustment for images acquisition.

Additive manufacturing of customized lower limb orthoses – A review

Additive manufacturing (AM) has been successfully applied in the healthcare and shows potential for modernization of lower limb orthoses manufacturing process. This study aims to analyze the scientific production of AM application in customized lower limb orthoses production (foot and ankle-foot orthoses) to identify possible research gaps. To reach the proposed objective, a systematic literature review was carried out, based on the construction of a bibliographic portfolio, a bibliometric study and on article content analysis. Some study gaps were identified as the cost of the 3D digitalizing and the additive manufacturing process employed. This review will be the basis for the development of research on the application of low cost 3D digitizing and 3D printing technologies in the development of lower limb orthoses.

3D Scanning and 3D Printing Technologies used in Albanian Heritage Preservation

In cultural heritage study of 3D modeling has become a very useful process to obtain indispensable data for documentation and visualization. 3D scanning and 3D printing suggest a vital solution in preserving and sustaining traditional folk costumes. 3D scanning and 3D digitizing is defined as the process of using metrological methods to ascertain the size and shape of a scanned object, which may often involve an optical device that rotates around the desired scanned model. In digital preservation, especially for three dimensional physical artifacts in various crafts, the geometric shape of an object is most important. The aim of this paper is to show 3D scanning technology that produces a high-precision digital reference document to provide virtual model for replication, and makes possible easy mass distribution of digital data. We also experimented with 3d Additive manufacturing or 3D printing to show a way to actualize digital forms of folk accessories for the experimental manufacturing and to show a way how to preserve nowadays the original object. The work includes scanning, modeling, and printing of waist coat and of coin handicrafts. Experiments will be carried out on 3d scanning, 3d modeling software, reconstruction and fabrication -rapid prototyping.

Photogrammetry and macro photography. The experience of the MUSINT II Project in the 3D digitizing process of small size archaeological artifacts

The MUSINT II project was created to publicize and promote the Minoan glyptic, a little-known archaeological heritage. Its contents were designed to involve both specialists and a general public (adults and children).The project focuses on the 3D digitalization of seventeen very small (about 15mm diameter) seals, stored in the archives of the National Archaeological Museum of Florence.The digitalization of these artifacts required a high-quality resolution technique capable of capturing their morphology and decorative motives and, at the same time, appeal to the educational targets.For this reason, the Structure from Motion (SfM) Photogrammetry was chosen. This technology makes it possible to obtain three-dimensional reproductions from random photographs made by non-dedicated devices, but the tiny-object survey required specific instruments and skills.A macrophotography technique was applied together with a specific workflow to obtain high quality photogrammetric models and to save time in acquiring and processing images. With this methodology, 3D models of high metric precision mesh and maximum color fidelity textures were obtained. This process delivers results of high level detail for low capital costs and minimal acquisition and processing time.