3D Point Cloud Reconstruction Using Inversely Mapping and Voting from Single Pass CSAR Images

3D reconstruction has raised much interest in the field of CSAR. However, three dimensional imaging results with single pass CSAR data reveals that the 3D resolution of the system is poor for anisotropic scatterers. According to the imaging mechanism of CSAR, different targets located on the same iso-range line in the zero doppler plane fall into the same cell while for the same target point, imaging point will fall into the different positions at different aspect angles. In this paper, we proposed a method for 3D point cloud reconstruction using projections on 2D sub-aperture images. The target and background in the sub-aperture images are separated and binarized. For a projection point of target, given a series of offsets, the projection point will be mapped inversely to the 3D mesh along the iso-range line. We can obtain candidate points of the target. The intersection of iso-range lines can be regarded as voting process. For a candidate, the more times of intersection, the higher the number of votes, and the candidate point will be reserved. This fully excavates the information contained in the angle dimension of CSAR. The proposed approach is verified by the Gotcha Volumetric SAR Data Set.

Use of the Modified Unilateral Cleft Lip Repair Technique to Establish a Cupid’s Bow With a Natural Structure

Introduction: There are several surgical techniques for unilateral cleft lip repair. In most of these techniques, the points where the postoperative scars cross the vermilion border are on the peak of the Cupid’s bow. These scars make the shape of Cupid’s bow indistinct. To maintain the natural shape of the Cupid’s bow, we modified the surgical technique. Methods: We modified the modified Millard’s surgical technique (Onizuka’s surgical technique). The main point of this modification was as follows: we combined a small triangular flap and a vermilion triangular flap (described by Noordhoff). We maintained the projection point on the lateral side of cleft lip which was coordinated to the peak of the Cupid’s bow. Results: We could preserve the shape and symmetry of the peak of the Cupid’s bow. Conclusion: To keep the projection point on the affected side of cleft lip and the surrounding vermilion border as one curve structure is important in maintaining the natural shape of the Cupid’s bow.

Point Orthogonal Projection onto a Spatial Algebraic Curve

Point orthogonal projection onto a spatial algebraic curve plays an important role in computer graphics, computer-aided geometric design, etc. We propose an algorithm for point orthogonal projection onto a spatial algebraic curve based on Newton’s steepest gradient descent method and geometric correction method. The purpose of Algorithm 1 in the first step of Algorithm 4 is to let the initial iteration point fall on the spatial algebraic curve completely and successfully. On the basis of ensuring that the iteration point fallen on the spatial algebraic curve, the purpose of the intermediate for loop body including Step 2 and Step 3 is to let the iteration point gradually approach the orthogonal projection point (the closest point) such that the distance between them is very small. Algorithm 3 in the fourth step plays an important double acceleration and orthogonalization role. Numerical example shows that our algorithm is very robust and efficient which it achieves the expected and ideal result.

A Three-Dimensional Guidance Logic for Continuous Curvature Path Following

A new simple and practical guidance logic is proposed for a vehicle to follow a general continuous curvature path defined in a three-dimensional space. The proposed guidance logic is formulated in such a way that the guidance law is to generate the command acceleration such that a vehicle pursues the designed moving virtual target, and this eventually makes a vehicle to follow a desired path. The position and velocity of the virtual target are specified explicitly by introducing the concept of the projection point and the tangentially receding distance. Numerical simulations are conducted to evaluate the precise path-following capability of the proposed guidance logic.

The Eustachian Tube as a Landmark for Early Identification of the Abducens Nerve During Endonasal Transclival Approaches

BACKGROUND Expanded endonasal approaches have the potential to injure the abducens nerve (cranial nerve [CN] VI). The nerve's root entry zone (REZ) and cisternal segment (CS) are particularly prone to injury during the clivus resection and dural incision of transclival approaches. OBJECTIVE To investigate the role of the eustachian tube (ET) as a surgical landmark for the REZ and CS of CN VI. METHODS Transclival expanded endonasal approaches were performed bilaterally in 6 fresh-frozen cadaveric specimens (12 sides). Anatomic relationships between ET and CN VI were documented with neuronavigation. RESULTS The mean vertical distance from the inferior brainstem point to the horizontal projection of CN VI REZ, CS midpoint, and interdural segment (ID) were 26.38 mm (95% confidence interval [CI] 17.36-35.4), 38.61 mm (95% CI 25.61-51.61), and 42.68 mm (95% CI 30.14-55.22), respectively. The relative vertical distance from the ET to the horizontal projections of the REZ, CS midpoint, and its ID were 6.43 mm (95% CI 3.25-9.61), 18.66 mm (95% CI 11.52-25.8), and 22.72 mm (95% CI 16.02-29.42), respectively. In the axial plane the angles between the ET and (1) the REZ and its midline horizontal projection point, (2) the midpoint and its midline horizontal projection point, and (3) ID and its midline horizontal projection point were 9.81 ± SD 5.20°, 18.50 ± SD 4.87°, and 24.71 ± SD 6.21°, respectively. CONCLUSION The ET may serve as a constant landmark to reliably predict the position of the REZ and CS of CN VI.

Design of Three-Dimensional Path Following Guidance Logic

This paper presents a three-dimensional path following guidance logic. The proposed guidance logic is composed of the guidance law and the motion strategy of virtual target along the desired path. The guidance law makes a vehicle purse the virtual target, and the motion strategy explicitly specifies the motion of virtual target by introducing the concept of the projection point and the tangentially receding distance. The proposed logic is simple and efficient and yet provides precise path following. Numerical simulations are performed to demonstrate the effectiveness of the proposed guidance logic.

Depth from Defocus via Active Multispectral Quasi-random Point Projections using Deep Learning

A novel approach for inferring depth measurements via multispectralactive depth from defocus and deep learning has been designed,implemented, and successfully tested. The scene is activelyilluminated with a multispectral quasi-random point pattern,and a conventional RGB camera is used to acquire images of theprojected pattern. The projection points in the captured image ofthe projected pattern are analyzed using an ensemble of deep neuralnetworks to estimate the depth at each projection point. A finaldepth map is then reconstructed algorithmically based on the pointdepth estimates. Experiments using different test scenes with differentstructural characteristics show that the proposed approachcan produced improved depth maps compared to prior deep learningapproaches using monospectral projection patterns.