geometric correction
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2021 ◽  
pp. 1651-1663
Author(s):  
Abdul Subhani Shaik ◽  
Ram Kumar Karsh ◽  
Merugu Suresh ◽  
Vinit Kumar Gunjan

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Wei Sun ◽  
Lijun Li

With the development of modern science and technology and more and more image processing systems, related technologies are becoming more and more complex. The application of image processing technology can be seen in various fields of society, such as medical field, aerospace field and life, and entertainment field. Due to the increasing amount of information on the picture, the requirements for the speed and clarity of image processing are also increasing. The existence of various external factors will lead to the production of image products and objects between the error and distortion problems. In order to make the process product design more authentic and reliable, this paper studies the process product design based on image processing multimode interaction. It uses radiometric correction and geometric correction to process distorted images and uses GPU parallel computing technology to accelerate the correction process. In this paper, this technology is applied to the visual recognition of welding robot, and the experiment shows that the product produced by the image processed by this module can obviously reduce the error.


2021 ◽  
Vol 13 (21) ◽  
pp. 4278
Author(s):  
Ying Zhang ◽  
Zhaohui Chi ◽  
Fengming Hui ◽  
Teng Li ◽  
Xuying Liu ◽  
...  

Ice Pathfinder (Code: BNU-1), launched on September 12, 2019, is the first Chinese polar observation microsatellite. Its main payload is a wide-view camera with a ground resolution of 74 m at the subsatellite point and a scanning width of 744 km. BNU-1 takes into account the balance between spatial resolution and revisit frequency, providing observations with finer spatial resolution than Terra/Aqua MODIS data and more frequent revisits than Landsat-8 OLI and Sentinel-2 MSI. It is a valuable supplement for polar observations. Geolocation is an essential step in satellite image processing. This study aims to geolocate BNU-1 images; this includes two steps. For the first step, a geometric calibration model is applied to transform the image coordinates to geographic coordinates. The images calibrated by the geometric model are the Level1A (L1A) product. Due to the inaccuracy of satellite attitude and orbit parameters, the geometric calibration model also exhibits errors, resulting in geolocation errors in the BNU-1 L1A product. Then, a geometric correction method is applied as the second step to find the control points (CPs) extracted from the BNU-1 L1A product and the corresponding MODIS images. These CPs are used to estimate and correct geolocation errors. The BNU-1 L1A product corrected by the geometric correction method is processed to the Level1B (L1B) product. Although the geometric correction method based on CPs has been widely used to correct the geolocation errors of visible remote sensing images, it is difficult to extract enough CPs from polar images due to the high reflectance of snow and ice. In this study, the geometric correction employs an image division and an image enhancement method to extract more CPs from the BNU-1 L1A products. The results indicate that the number of CPs extracted by the division and image enhancements increases by about 30% to 182%. Twenty-eight images of Antarctica and fifteen images of Arctic regions were evaluated to assess the performance of the geometric correction. The average geolocation error was reduced from 10 km to ~300 m. In general, this study presents the geolocation method, which could serve as a reference for the geolocation of other visible remote sensing images for polar observations.


2021 ◽  
Vol 33 (5) ◽  
pp. 1155-1168
Author(s):  
Kenta Tanaka ◽  
Motoyasu Sano ◽  
Yumi Horimai ◽  
Hideyoshi Horimai ◽  
Yusuke Aoki ◽  
...  

In recent years, there has been an increasing need for larger screens and higher definition displays, while projectors are becoming smaller and cheaper. Furthermore, an ultra-short-throw projector that can display on a large screen while significantly reducing the distance between the projector and screen is being developed. However, ultra-short-throw projectors are required to be precisely aligned with the screen, and if the screen is not flat, the projected image becomes distorted. Therefore, geometric correction projection technology is attracting attention for projection on curtains and the walls of living rooms instead of screens for realizing the correction of distortion during projection with ultra-short-throw projectors, projection mapping, signage, etc. We focused on developing a hologram with perfect command of the ray. Conventional geometry-correction systems are expensive systems that require a personal computer and a camera. In this study, we developed a geometric correction method applying holographic ray direction control technology to control a holographic ray at a low cost and in real time. In this paper, we studied the exposure technology and proposed a ray-direction control technology that combines a scanning laser projector that uses a hologram and a micro electro mechanical systems mirror. We also proposed and demonstrated the basic principle of a holographic surface projector (HSP), which uses hologram geometry correction technology. Finally, we constructed a geometrically corrected hologram exposure system using a depth camera and conducted geometrically corrected projection experiments.


2021 ◽  
Vol 13 (16) ◽  
pp. 3329
Author(s):  
Bowen Bie ◽  
Yinghui Quan ◽  
Kaijie Xu ◽  
Guangcai Sun ◽  
Mengdao Xing

This paper proposes an imaging algorithm for synthetic aperture radar (SAR) mounted on a high-speed maneuvering platform with squint terrain observation by progressive scan mode. To overcome the mismatch between range model and the signal after range walk correction, the range history is calculated in local polar format. The Doppler ambiguity is resolved by nonlinear derotation and zero-padding. The recovered signal is divided into several blocks in Doppler according to the angular division. Keystone transform is used to remove the space-variant range cell migration (RCM) components. Thus, the residual RCM terms can be compensated by a unified phase function. Frequency domain perturbation terms are introduced to correct the space-variant Doppler chirp rate term. The focusing parameters are calculated according to the scene center of each angular block and the signal of each block can be processed in parallel. The image of each block is focused in range-Doppler domain. After the geometric correction, the final focused image can be obtained by directly combined the images of all angular blocks. Simulated SAR data has verified the effectiveness of the proposed algorithm.


Measurement ◽  
2021 ◽  
pp. 109703
Author(s):  
Sepideh Akhbarifar ◽  
Nicholas A. Mecholsky ◽  
Marek Brandys ◽  
Werner Lutze ◽  
Ian L. Pegg

2021 ◽  
pp. 939
Author(s):  
Winhard Tampubolon ◽  
Wolfgang Reinhardt ◽  
Franz Josef Behr

Due to its large area Large Scale Topographic Mapping (LSTM) for Indonesia requires acceleration strategies that must be innovative enough to take into account the production efficiency. Satellite-based technologies are still a preferable choice especially in conjunction with the security clearance and weather. Standards for the Very High-Resolution Satellite Imagery (VHRS) utilization are essential, especially in a situation where there are so many available sensors and processing methods implemented. Hence, the selection of a proper geometric correction method is fundamental in order to utilize the VHRS imagery as one source of geospatial data especially for LSTM production and updating purposes. For CSRT geometric correction, an orthorectification process is required, where this process requires input data from the Ground Control Point (TKT) and the Digital Elevation Model (DEM). Therefore, the Least Square Adjustment (LSA) method is implemented to be able to include 8-9 GCPs per-scene (orbital and sensor parameters) and the DEM with a maximum resolution 4 times of the VHRS imagery’s Ground Sampling Distance (GSD) in the process of producing VHRS orthoimages. In addition, the role of orbital and sensor parameters is also essential for the geometric correction because its relation to the Direct Georeferencing (DG) of each pixel by Rigorous Sensor Model (RSM) approach. However, in the situation where the reliable orbital and sensor parameters are not available, the Rational Function Model (RFM) can be used as an alternative solution for the geometric correction of VHRS imagery. This paper discusses the VHRS utilization with a comprehensive approach that can be implemented in a local coordinate system i.e. the Indonesian Geospatial Reference System for the production of the reliable VHRS imageries.


2021 ◽  
Author(s):  
Zhili Zhou ◽  
Jianyu Zhu ◽  
Yuecheng Su ◽  
Meimin Wang ◽  
Xingming Sun

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