scholarly journals Astrometry test of MSCRED IRAF software package

2005 ◽  
pp. 123-125
Author(s):  
R. Popescu ◽  
P. Popescu ◽  
P. Paraschiv ◽  
A. Nedelcu
Keyword(s):  
Coordinate System ◽  
Software Package ◽  
Open Cluster ◽  
Ccd Camera ◽  
Field Size ◽  
World Coordinate System ◽  
The World ◽  
Ccd Observations ◽  
Cassegrain Telescope

Astrometric properties of images obtained using MSCRED IRAF software package are investigated. CCD observations of M35 open cluster were taken in an observation run between October 10 and 17, 2004 at Belogradchick Observatory (Bulgaria) using the 60cm Cassegrain telescope endowed with a 1kX1k Apogee 47P CCD camera, ensuring to a field size of 6.16 square minutes, with a scale of 0.722arcsec/pixel in 2X2 binned mode. Dithered images are resampled and reansambled into a single larger image for which the World Coordinate System (WCS) solution is recomputed and investigated. .

scholarly journals A Novel AVM Calibration Method Using Unaligned Square Calibration Boards

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2265
Author(s):  
Jung Hyun Lee ◽  
Dong-Wook Lee
Keyword(s):  
Coordinate System ◽  
Reference Data ◽  
Side Information ◽  
Reference Sample ◽  
Likelihood Estimation ◽  
Calibration Method ◽  
World Coordinate System ◽  
Sample Data ◽  
The World ◽  
Left And Right

An around view monitoring (AVM) system acquires the front, rear, left, and right-side information of a vehicle using four cameras and transforms the four images into one image coordinate system to monitor around the vehicle with one image. Conventional AVM calibration utilizes the maximum likelihood estimation (MLE) to determine the parameters that can transform the captured four images into one AVM image. The MLE requires reference data of the image coordinate system and the world coordinate system to estimate these parameters. In conventional AVM calibration, many aligned calibration boards are placed around the vehicle and are measured to extract the reference sample data. However, accurately placing and measuring the calibration boards around a vehicle is an exhaustive procedure. To remediate this problem, we propose a novel AVM calibration method that requires only four randomly placed calibration boards by estimating the location of each calibration board. First, we define the AVM errors and determine the parameters that minimize the error in estimating the location. We then evaluate the accuracy of the proposed method through experiments using a real-sized vehicle and an electric vehicle for children to show that the proposed method can generate an AVM image similar to the conventional AVM calibration method regardless of a vehicle’s size.

Vilnius Multicolor CCD Photometry of the Open Cluster NGC 752

2011 ◽  
Vol 20 (1) ◽  
Author(s):  
S. Bartašiūtė ◽  
R. Janusz ◽  
R. P. Boyle ◽  
A. G. Davis Philip
Keyword(s):  
Open Cluster ◽  
Central Area ◽  
Ccd Camera ◽  
Advanced Technology ◽  
Ccd Photometry ◽  
Intermediate Band ◽  
Color Indices ◽  
Ccd Observations ◽  
Low Mass ◽  
Absolute Magnitudes

AbstractWe have performed multicolor CCD observations of the central area of NGC 752 to search for faint, low-mass members of this open cluster. Four 12’ x 12’ fields were taken on the 1.8 m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) using a 4K CCD camera and eight intermediate-band filters of the Strömvil (Strömgren + Vilnius) system. In this paper we present a catalog of photometry for 405 stars down to the limiting magnitude V = 18.5, which contains V magnitudes and color indices of the Vilnius system, together with photometric determinations of spectral types, absolute magnitudes M

scholarly journals Structured Light 3D Reconstruction System Based on a Stereo Calibration Plate

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 772
Author(s):  
Meiying Li ◽  
Jin Liu ◽  
Haima Yang ◽  
Wanqing Song ◽  
Zihao Yu
Keyword(s):  
Coordinate System ◽  
Structured Light ◽  
Primary Objective ◽  
Calibration Data ◽  
Complex Objects ◽  
World Coordinate System ◽  
Calibration Methods ◽  
The World ◽  
Stereo Calibration ◽  
Left And Right

Calibration is a critical step in structured light 3D imaging systems. However, in the traditional calibration process, since the calibration plate is based on a two-dimensional model, the flatness of the calibration plate and the angle of the photo will affect the subsequent stitching steps based on the feature points. The number of photos also affects the calibration results. To improve the calibration accuracy, multiple photos need to be taken. The primary objective of this study was to achieve the simple and fast calibration of system parameters, so a method obtaining a large number of calibration data by homography matrix is presented, and a corresponding stereo target is designed in symmetry. First, using the relationship between the corner coordinates of the left and right parts of the stereo calibration plate and the coordinates of the world coordinate system, the homography matrix of the left and right calibration plates from the image coordinates to the world coordinates is calculated. Second, all the pixels in the stereo calibration plate are matched to the world coordinate system by using the homography matrix. In addition, we also compared the results of this method with those of traditional calibration methods. The experimental results show that the 3D geometric surface of the reconstruction result is smooth, it avoids the missing parts and the visual effect is excellent. Furthermore, the error range of small and complex objects can be reduced to 0.03 mm~0.05 mm. This method simplifies the calibration steps, reduces the calibration costs and has practical application value.

scholarly journals Multicolor CCD photometry of the open cluster NGC 752

2009 ◽  
Vol 5 (S266) ◽  
pp. 361-364
Author(s):  
Stanislava Bartašiūtė ◽  
Robert Janusz ◽  
Richard P. Boyle ◽  
A. G. Davis Philip ◽  
Viktoras Deveikis
Keyword(s):  
Main Sequence ◽  
Open Cluster ◽  
Ccd Camera ◽  
Advanced Technology ◽  
Ccd Photometry ◽  
Intermediate Band ◽  
Individual Stars ◽  
Ccd Observations ◽  
Low Mass

AbstractWe obtained CCD observations of the open cluster NGC 752 with the 1.8m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) with a 4K CCD camera and eight intermediate-band filters of the Stromvil (Strömgren + Vilnius) system. Four 12′ × 12′ fields were observed, covering the central part of the cluster. The good-quality multicolor data made it possible to obtain precise estimates of distance moduli, metallicity and foreground reddening for individual stars down to the limiting magnitude, V = 17.5, enabling photometric identification of faint cluster members. The new observations provide an extension of the lower main sequence to three magnitudes beyond the previous (photographic) limit. A relatively small number of photometric members identified at fainter magnitudes seems to be indicative of actual dissolution of the cluster from the low-mass end.

An Orthogonal Wheel Odometer for Positioning in a Relative Coordinate System on a Floating Ground

2021 ◽  
Vol 11 (23) ◽  
pp. 11340
Author(s):  
Zhiguo Lu ◽  
Guangda He ◽  
Ruchao Wang ◽  
Shixiong Wang ◽  
Yichen Zhang ◽  
...  
Keyword(s):  
Coordinate System ◽  
Current Method ◽  
Maximum Error ◽  
Floating Platform ◽  
Time Data ◽  
Sensing System ◽  
World Coordinate System ◽  
Sliding Mechanism ◽  
The World ◽  
Omnidirectional Wheels

This paper introduces a planar positioning sensing system based on orthogonal wheels and encoders for some surfaces that may float (such as ship decks). The positioning sensing system can obtain the desired position and angle information on any such ground that floats. In view of the current method of using the IMU gyroscope for positioning, the odometer data on these floating grounds are not consistent with the real-time data in the world coordinate system. The system takes advantage of the characteristic of the orthogonal wheel, using four vertical omnidirectional wheels and encoders to position on the floating ground. We design a new structure and obtain the position and angle information of a mobile robot by solving the encoder installed on four sets of omnidirectional wheels. Each orthogonal wheel is provided with a sliding mechanism. This is a good solution to the problem of irregular motion of the system facing the floating grounds. In the experiment, it is found that under the condition that the parameters of the four omnidirectional wheels are obtained by the encoder, the influence of the angle change of the robot in the world coordinate system caused by the flotation of the ground can be ignored, and the position and pose of the robot on the fluctuating ground can be well obtained. Regardless of straight or curved motion, the error can reach the centimeter level. In the mobile floating platform experiment, the maximum error of irregular movement process is 2.43 (±0.075) cm and the RMSE is 1.51 cm.

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