The distortion of images in remote sensing systems at arbitrary angles of sight

2021 ◽  
Vol 27 (3) ◽  
pp. 51-65
Author(s):  
V.G. Kolobrodov ◽  
◽  
N.I. Lykholit ◽  
V.M. Tiagur ◽  
B.Yu. Pinchuk ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Mathematical Model ◽  
Image Quality ◽  
Service Life ◽  
Movement Speed ◽  
High Price ◽  
Integration Time ◽  
Thermal Detector ◽  
Spatial Frequencies

Background. The main problem in launching space optical and electronic viewing systems (OEVS) for remote sensing of the Earth can be regarded as their high price, which even the leading countries of the world are not always ready to pay. Therefore, the quality of spacecraft systems imposed the most stringent requirements. One of the economically expedient options to increase the efficiency of space OEVS is scanning the Earth’s surface at arbitrary angles of sighting, which allows for the same time of service life to collect more information, but this in turn leads to image distortion. Therefore, analysis of the resulting image quality depending on the angles of sighting of the OEVS is an actual task that will assess the capabilities of the system and its conformance with the established requirements. Objective. Improving the physical and mathematical model of the modulation transfer function of the system “lens – matrix detector” and the study of the dependence of spatial and radiometric resolution on the angles of sight for the space OEVS when the sighting axis deviates from the nadir. Methods. Based on the analysis of signal generation models for television and thermal imaging space OEVS, it is proposed to use the concept – the contrast gray body. In the physical and mathematical model, it is proposed normalize to the spatial frequencies of objects at different angles of sight to the spatial frequencies in the nadir, and to calculate the radiometric resolution take into account the transmission and rarefied of the atmosphere, the image movement speed on the detector and its integration time. Results. Practical results of calculations of the offered physical and mathematical model for space OEVS showed that at deviation from nadir the effective spatial bandwidth worsens and at the specified parameters of system it is inexpedient scanning at angles of sighting greater than 30º. Accordingly, a comparative analysis of radiometric resolution for different type of detectors showed that the use of a photonic detector gives ~1.4 times better resolution in the nadir as opposed to the use of thermal detector and almost identical results are obtained at maximum angles of sighting. Also, a significant impact is made by a decrease a coefficient of atmospheric transmittance due to the rarefied of the atmosphere, which reaches from 26% to 45% that depends on the spectral range. Conclusions. Analysis of the results of the study confirms the possibility that photonic detectors can be replaced by modern thermal detectors with insignificant loss of image quality of the resulting image, which can significantly increase the service life of space OEVS.

Study Method for Testing Image Quality of Optical Remote Sensing Satellite of Vietnam

2018 ◽  
Vol 2 (9) ◽  
Author(s):  
Nghiem Van Tuan ◽  
◽  
Nguyen Minh Ngoc ◽  
Tran Van Anh ◽  
Do Thi Phuong Thao ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Image Quality ◽  
Optical Remote Sensing ◽  
Remote Sensing Satellite

Remote sensing image quality evaluation based on deep learning

2021 ◽  
pp. 1-9
Author(s):  
Tong Wang ◽  
Hemeng Yang ◽  
Ling Zhu ◽  
Yazhou Fan ◽  
Xue Yang ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Image Quality ◽  
Quality Evaluation ◽  
Remote Sensing Image ◽  
Human Vision ◽  
Remote Sensing Images ◽  
Image Quality Evaluation ◽  
Remote Sensing Technology ◽  
Sensing Technology

Remote sensing technology is an effective tool for sensing the earth’s surface. With the continuous improvement of remote sensing technology, remote sensing detectors can obtain more spectral and spatial information, including clear feature contours, complex texture features and spatial layout rules. This information was detected in mineral resources. Surface substance identification, water pollution information monitoring and many other aspects have played an important role. The coding algorithm and defects, storage algorithm and interference from atmospheric cloud radiation information during the imaging process lead to varying degrees of distortion and deterioration of remote sensing images during imaging, transmission and storage. This makes it difficult to process, analyze and apply remote sensing images. Therefore, the design of a reasonable remote sensing image quality evaluation method is not only conducive to the remote sensing image quality evaluation in the real-time processing system of remote sensing image, but also conducive to the optimization of remote sensing image system and image processing algorithm. The application is worthwhile. In this paper, the deteriorating features of remote sensing images will change the statistical distribution. We propose a method for evaluating the quality of remote sensing images in depth learning. Feature learning and blurring as well as noise intensity classification for image remote sensing using convolutional neural network are carried out. The evaluation model is modified by masking effect and perceptual weighting factor, and the quality evaluation results of remote sensing images are obtained according to human vision. The research shows that this method can effectively solve the problem of removing and evaluating the noise of remote sensing image, and can effectively and accurately evaluate the quality of remote sensing image. It is also consistent with subjective assessment and human perception.

Observability of Very Thick Specimen by Using Transmission Scanning Electron Microscope

1971 ◽  
Vol 29 ◽  
pp. 26-27
Author(s):  
K. Shibatomi ◽  
T. Yamanoto ◽  
H. Koike
Keyword(s):  
Electron Microscope ◽  
Image Quality ◽  
Scanning Electron Microscope ◽  
Chromatic Aberration ◽  
Image Contrast ◽  
Objective Lens ◽  
Thick Specimen ◽  
Transmission Electron ◽  
Scanning Electron

In the observation of a thick specimen by means of a transmission electron microscope, the intensity of electrons passing through the objective lens aperture is greatly reduced. So that the image is almost invisible. In addition to this fact, it have been reported that a chromatic aberration causes the deterioration of the image contrast rather than that of the resolution. The scanning electron microscope is, however, capable of electrically amplifying the signal of the decreasing intensity, and also free from a chromatic aberration so that the deterioration of the image contrast due to the aberration can be prevented. The electrical improvement of the image quality can be carried out by using the fascionating features of the SEM, that is, the amplification of a weak in-put signal forming the image and the descriminating action of the heigh level signal of the background. This paper reports some of the experimental results about the thickness dependence of the observability and quality of the image in the case of the transmission SEM.

Organ doses and subjective image quality of indirect digital panoramic radiography

2001 ◽  
Vol 30 (6) ◽  
pp. 308-313 ◽  
Author(s):  
F Gijbels ◽  
G Sanderink ◽  
C Bou Serhal ◽  
H Pauwels ◽  
R Jacobs
Keyword(s):  
Image Quality ◽  
Panoramic Radiography ◽  
Organ Doses ◽  
Subjective Image Quality ◽  
Digital Panoramic Radiography
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