Simple Line Patterns Research Articles

Automatic Data Selection and Boresight Adjustment of LiDAR Systems

This paper details a new automatic calibration method for the boresight angles between a LiDAR (Light Detection and Ranging) and an inertial measurement unit (IMU), based on a data selection algorithm, followed by the adjustment of boresight angles. This method, called LiDAR-IMU boresight automatic calibration (LIBAC), takes in input overlapping survey strips following simple line patterns over regular slopes. We first construct a boresight error observability criterion, used to select automatically the most sensitive points to boresight errors. From these points, we adjust the boresight angles. From a statistical analysis of the adjustment results, we derive the boresight angle precision. Results obtained with LIBAC on several LiDAR system integrated within drones are presented. We also give results about the reproducibility of the method.

Multibeam Echo Sounders-IMU Automatic Boresight Calibration on Natural Surfaces

ABSTRACTThis paper details a new boresight calibration method for multibeam echo sounder systems This method is based on an automatic data selection algorithm, followed by a boresight least squares adjustment This method, called MIBAC (MultiBeam-IMU Boresight Automatic Calibration), takes in input overlapping survey strips following a simple line pattern over a regular slope. We first construct a boresight error observability criterion, used to select automatically the most sensitive soundings to boresight errors. From these soundings, we perform a 3D adjustment of the boresight angle, thus taking into account the coupling between angles. From a statistical analysis of the adjustment results, we derive the boresight angle precision. Numerical results obtained with four different multibeam echo sounder systems are presented and compared to those of a patch test calibration method. Finally, we demonstrate the performances of MIBAC through a standard deviation along the surface normal approach computed by principal component analysis.

Simple micropatterning method for enhancing fusion efficiency and responsiveness to electrical stimulation of C2C12 myotubes.

Cultured myotubes induced in vitro from myoblast cell lines have been widely used to investigate muscle functional properties and disease-related biological phenotypes. Until now, several cell patterning techniques have been applied to regulate in vitro myotube structures. However, these previous studies required specific geometry patterns or soft materials for inducing efficient myotube formation. Thus, more simple and easy handling method will be promising. In this study, we aimed to provide a method to form C2C12 myotubes with regulated sizes and orientations in simple line patterns. We used a poly(dimethylsiloxane) (PDMS) stamp and a 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer solution to fabricate line patterns for myotube formation onto a culture dish. We confirmed that C2C12 myotubes of well-defined size and orientation were reproducibly formed. In particular, myotubes formed in the micropatterned lines showed the increased fusion efficiency. Then, functional dynamics in the micropatterned myotubes were detected and analyzed using a calcium imaging method. We confirmed micropatterning in line patterns enhanced the responsiveness of myotubes to external electrical stimulations. These results indicate that micropatterning myoblasts with the MPC polymer is a simple and effective method to form functional myotube networks.

Scan Projection Optical Lithography through a Slit onto Small Diameter Shafts

Scan projection optical lithography onto small diameter shafts were investigated. It will be useful for printing complicated patterns including cross points or elbow points instead of laser direct writing. A specimen shaft coated with a resist film was synchronously rotated during the continuous linear scan of a flat reticle. Because the shaft surface was curved in an arc, instantaneous exposure field should be limited to a narrow area near the top surface of the shaft, where the surface was regarded almost flat. Accordingly, an allowable width of the slit limiting the exposure area was discussed considering defocus, pattern position shift, and width swelling. Pattern width target was 50-100 μm onto 1 or 2 mm diameter shafts because an immediate application was to print helical shaft patterns for micro-axial pumps. The slit width had to be less than approximately 30% of the shaft diameter to print 100-?m wide patterns clearly. The cross patterns were printed as clearly as the simple line patterns, and width and pitch variations were sufficiently small.

Memories of a fruitfly

Despite its tiny size, the fruitfly brain is staggeringly intricate. So teasing apart how it remembers things — even a simple line pattern — is a daunting task. Progress is being made, thanks to genetic innovations. Like humans, Drosophila fruit flies recognize and remember visual landmarks, and they recognize patterns (such as vertical or oblique bars) independently of where they are projected on the retina at first encounter. In an experiment using genetic manipulation and a fruit-fly flight simulator, the nerve cells required for these feats of visual memory have been identified for the first time in an insect. Two groups of about 20 neurons are found in two narrow strata in the ‘fan-shaped body’, the largest component of the central complex that is characteristic of the arthropod brain. The main role of the central complex was thought to be to integrate information in the two brain hemispheres; this new study is the first to attribute well defined behavioural functions to this brain region.

Metrical information load of lines and angles in line patterns.

Acute angles and long lines are more complex than obtuse angles and short lines. This source of complexity is called metrical information, for which a measure was proposed by Leeuwenberg (1982). According to this measure, the metrical information of a static pattern is specified as the sum of the mechanical impulses necessary to move an object according to this pattern. The perceptual relevance of this metrical load was tested in an experiment in which judged complexities were gathered for a number of simple line patterns.

Mental imagery and dyslexia: A deficit in processing multipart visual objects?

Dyslexic and normal control subjects memorized simple line patterns inside a grid and subsequently judged whether an “X” would have fallen on the pattern had it been present in an empty grid. The patterns were letters and novel shapes. The grids were presented to the left visual field, to the right visual field, or in central vision. Dyslexic subjects had difficulty generating images of multipart patterns, but this deficit was limited to letters. The findings suggest that dyslexics may have selective difficulty integrating visual information stored in long-term memory.

On the spread of suppression and binocular rivalry

Suppression during rivalry between line patterns extends beyond the place of overlap of superposed lines. It spreads to encompass more distant portions of the non-dominant line. This spread of suppression was measured in simple line patterns. Its magnitude was found to vary with non-conjugate eye movements, but not to be entirely dependent upon them. An explanation of the contribution of eye movements was offered in terms of a time-lag in recovery from local suppression. Rivalry was found to occur when luminous areas were partially superposed but not when they were in register with each other.