The design of the sampling parameters for CMM of free-form surfaces

In order to improve the inspection accuracy of free-form surface by CMM, this paper adopted the different sampling parameters to research the influence of the measurement accuracy of free-form surface. Through the combination of area uniform block random sampling and Latin hypercube random sampling, the minimum sampling grid block area and ball diameter were taken as the research parameters. Firstly, this research analysed theoretically the influence of measurement accuracy of free-form surface by different sampling parameters. Secondly, carrying out experiments verified the analytical results. Then, the influence of two groups of sampling parameters on the normal deviation of free-form surface could be acquired by analysing the experimental data. Finally, this research could obtain the result of normal deviation of free-form surface. The research results showed that the minimum block area of sampling and the diameter of measuring ball become smaller, and the profile error become larger when the number of measuring points were the same, the more it can reflect the actual contour of the free-form surface, which proves that the measurement accuracy is higher.

Layer contour characterization in additive manufacturing through image binarization

On-Machine Measurement adoption will be key to dimensional and geometrical improvement of additively manufactured parts. One possible approach based on OMM aims at using digital images of manufactured layers to characterize actual contour deviations with respect to their theoretical profile. This strategy would also allow for in-process corrective actions. This work describes a layer-contour characterization procedure based on binarization of digital images acquired with a flat-bed scanner. This procedure has been tested off-line to evaluate the influence of two of the parameters for image treatment, the median filter size (S f ) and the threshold value (T), on the dimensional/geometrical reliability of the contour characterization. Results showed that an appropriate selection of configuration parameters allowed to characterize the proposed test-target with excellent coverage and reasonable accuracy.

Edge detection in Cassini astronomy image using Extreme Learning Machine

Edge detection is often performed on disc-like object in Cassini astronomy images to accurately obtain the object’s center position. The existing edge extraction methods usually produce lots of false edge pixels because of noise and the interior details in disc-like objects. In the paper, an edge detection algorithm based on Extreme Learning Machine (ELM) is proposed for Cassini astronomy images. In the ELM model, a 28-D feature vector of a pixel in Cassini image is constructed as input, which consists of first and second derivatives and some Haar-like features, and a binary classifier is obtained as output that tells if the pixel is in edge. The experimental result shows that its performance is much better than traditional operators. The detected edge is closer to the actual contour. Its average accuracy is 0.9379. The algorithm can be applied to edge detection of disc-like objects in astronomy images.

Dorsal Augmentation Using Autologous Costal Cartilage or Microfat-Infused Soft Tissue Augmentation

Costal cartilage grafting is increasing in popularity with increased demand for augmentation rhinoplasty and increased need for grafting material for structure rhinoplasty techniques. Use of costal cartilage for dorsal grafting is both art and science. The art is demonstrated in the act of carving a dorsal graft that will reflect the actual contour of the nasal dorsum. The science is linked to the methodology of how the grafts are contoured to match the patient's desires and how the graft is fixed to the bony dorsum to minimize the risk of warping and displacement. Variations in dorsal graft design and methods of fixation are described. Use of the perichondrial interface between dorsal graft and perforated/rasped nasal dorsum acts to ossify the dorsal graft to the underlying bone, creating an immobile and natural appearing nasal dorsum. The fixation of the dorsal graft limits movement and hence decreases the likelihood of warping or deformity. Use of microfat in rhinoplasty has tremendous potential for camouflage and to promote healing of compromised tissues. Using microfat-infused soft tissue augmentation (MISTA), the surgeon is able to deliver microfat to an open surgical field, promote healing, and provide soft tissue augmentation. In this technique, microfat is injected into soft tissue carriers (perichondrium, temporalis fascia, etc.) and then implanted into the surgical field. MISTA has tremendous potential utility in many areas of cosmetic and reconstructive surgery.

Research of ASM Object Tracking Method Combining Kalman Estimation

ASM is a statistical model applied to match contours of non-rigid object. The actual contour may much different from the initial contour and the result is likely to converge to an error contour. Kalman filter is adopted to track the current frame for the prediction and acts as the initial state of the ASM, and then applies the ASM to correct the contour of the object. Experimental results show that the method proposed in this paper allows the model to converge to the target contour quickly and accurately. It has good stability and robustness.

Lossless contour coding using elastic curves in multiview video plus depth

Multiview video plus depth is emerging as the most flexible format for three-dimensional video representation, as witnessed by the current standardization efforts by ISO and ITU. In particular, in depth representation, arguably the most important information lies in object contours. As a consequence, an interesting approach consists in performing a lossless coding of object contours, possibly followed by a lossy coding of per-object depth values. In this context, we propose a new technique for lossless coding of object contours, based on the elastic deformation of curves. Using the square-root velocity representation for the elements of the space of curves, we can model a continuous evolution of elastic deformations between two reference contour curves. An elastically deformed version of the reference contours can be sent to the decoder with a reduced coding cost and used as side information to improve the lossless coding of the actual contour. Experimental results on several multiview video sequences show remarkable gains with respect to the reference techniques and to the state of the art.

Design of the Disc Cam Profile with Negative Radius Translating Roller Follower

This paper is to study the force-locking and shape-locking conjugate cam mechanisms. problems of the theoretical and actual contour of the cams with negative radius translation roller follower are solved by the use of "definite proportion and division point" method. The results could lead an important foundation for further research of the new type cam mechanisms.

The Hydraulic Manifold Block Pore Checking CAD Explore

This paper presents hydraulic manifold block in the check of different surface channel relative position relations, according to the manifold pores the characteristics, the same face pores, the pro face pores, the opposite faces pores is divided into the holes in three forms, analysis of the cylindrical duct end taper hole data on pore flow quality influence. The cylindrical and conical surface of actual contour curve projection and intersection check channel on-off relationship; focus on the analysis of the pore wall thickness, pore flow quality.

Measurement of Structure’s Image Primitive Based on Power-Law

In industrial machine vision (MV) applications, it is a popular research direction to identify a structure mechanical part image primitive’s relationship with its background by extracting actual contour from a captured image. However, numerous nonlinear problems turn up in MV applications of measuring and inspecting mechanical parts. Those problems are brought by components of MV system including lens, cameras, lighting effect, and sheltered measured object. These nonlinear phenomena usually result in incomplete and inconsistent geometrical shape of a structure’s image primitive. Therefore, special primitive measurement theory and method are researched in the thesis, on the basis of analyzing fractal and structural features of mechanical parts. The method found that an important trait of mechanical parts image contour which can be used to reduce the impact of nonlinear phenomena and determine a closest contour of the image primitive by using different multi-scale rulers in measuring. The effect of the measurement method is proved by an example in cylindrical connectors’ inspection.