Robust Shape Fitting via Peeling and Grating Coresets

Shape Fitting and Morphometric Analysis of Open Curves Based on Discrete Cosine Transform

2020 IEEE International Conference on Mechatronics and Automation (ICMA) ◽

10.1109/icma49215.2020.9233864 ◽

2020 ◽

Author(s):

Shengmin Zhou ◽

Bingiue Li

Keyword(s):

Discrete Cosine Transform ◽

Morphometric Analysis ◽

Cosine Transform ◽

Shape Fitting

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A Two-Step Phenotypic Parameter Measurement Strategy for Overlapped Grapes under Different Light Conditions

Sensors ◽

10.3390/s21134532 ◽

2021 ◽

Vol 21 (13) ◽

pp. 4532

Author(s):

Yubin Miao ◽

Leilei Huang ◽

Shu Zhang

Keyword(s):

Edge Detection ◽

Parameter Measurement ◽

Average Error ◽

Projection Area ◽

Shape Fitting ◽

Multi Scale ◽

Image Pyramids ◽

Phenotypic Parameter ◽

Contour Fitting ◽

Image Edge

Phenotypic characteristics of fruit particles, such as projection area, can reflect the growth status and physiological changes of grapes. However, complex backgrounds and overlaps always constrain accurate grape border recognition and detection of fruit particles. Therefore, this paper proposes a two-step phenotypic parameter measurement to calculate areas of overlapped grape particles. These two steps contain particle edge detection and contour fitting. For particle edge detection, an improved HED network is introduced. It makes full use of outputs of each convolutional layer, introduces Dice coefficients to original weighted cross-entropy loss function, and applies image pyramids to achieve multi-scale image edge detection. For contour fitting, an iterative least squares ellipse fitting and region growth algorithm is proposed to calculate the area of grapes. Experiments showed that in the edge detection step, compared with current prevalent methods including Canny, HED, and DeepEdge, the improved HED was able to extract the edges of detected fruit particles more clearly, accurately, and efficiently. It could also detect overlapping grape contours more completely. In the shape-fitting step, our method achieved an average error of 1.5% in grape area estimation. Therefore, this study provides convenient means and measures for extraction of grape phenotype characteristics and the grape growth law.

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Repair of critical-size porcine craniofacial bone defects using a collagen-polycaprolactone composite biomaterial

10.1101/2021.04.19.440506 ◽

2021 ◽

Author(s):

Marley J Dewey ◽

Derek J Milner ◽

Daniel Weisgerber ◽

Colleen Flanagan ◽

Marcello Rubessa ◽

...

Keyword(s):

Bone Formation ◽

Bone Regeneration ◽

Fibrous Tissue ◽

Bone Defects ◽

Large Animal ◽

Collagen Scaffolds ◽

Shape Fitting ◽

Large Animal Models ◽

3D Printed ◽

Mineralized Collagen

Regenerative medicine approaches for massive craniomaxillofacial bone defects face challenges associated with the scale of missing bone, the need for rapid graft-defect integration, and challenges related to inflammation and infection. Mineralized collagen scaffolds have been shown to promote mesenchymal stem cell osteogenesis due to their porous nature and material properties, but are mechanically weak, limiting surgical practicality. Previously, these scaffolds were combined with 3D-printed polycaprolactone mesh to form a scaffold-mesh composite to increase strength and promote bone formation in sub-critical sized porcine ramus defects. Here, we compare the performance of mineralized collagen-polycaprolactone composites to the polycaprolactone mesh in a critical-sized porcine ramus defect model. While there were no differences in overall healing response between groups, our data demonstrated broadly variable metrics of healing regarding new bone infiltration and fibrous tissue formation. Abscesses were present surrounding some implants and polycaprolactone polymer was still present after 9-10 months of implantation. Overall, while there was limited successful healing, with 2 of 22 implants showed substantial levels of bone regeneration, and others demonstrating some form of new bone formation, the results suggest targeted improvements to improve repair of large animal models to more accurately represent craniomaxillofacial bone healing. Notably, strategies to increase osteogenesis throughout the implant, modulate the immune system to support repair, and employ shape-fitting tactics to avoid implant micromotion and resultant fibrosis. Improvements to the mineralized collagen scaffolds involve changes in pore size and shape to increase cell migration and osteogenesis and inclusion or delivery of factors to aid vascular ingrowth and bone regeneration.

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