• Aerospace Engineering and Technology
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• v.10 no.2
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• pp.101-104
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• 2011

For high resolution electro-optical payload, the alignment and assembly of the secondary mirror with respect to the primary mirror is the most important step of the whole camera assembly process. For the purpose of the secondary mirror alignment, Wave front sensor and Collimator would rather be useful than the interferometer because of its small size and easiness of handling. In this paper the brief alignment procedure and method of the secondary mirror of a high resolution electro-optical camera system was introduced.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.1
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• pp.87-94
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• 2005

This paper is about the compensation of phase angle error and amplitude difference in stationary 2 pole coordinates by the installation variation of sensor at low cost high resolution digital hybrid encoder. To solve the problem of amplitude difference at the existing hybrid encoder, we normalized the relative magnitude of the two analog signals. and also to solve the problem of installation variation when installed the sensor, we rotate the stationary 2 pole coordinates to compensate the location error of sensor. and we used and tested the QEP function and A/D port in DSP(TMS320F2812) to verify the mentioned proposed method.

• Korean Journal of Remote Sensing
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• v.38 no.5_1
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• pp.523-533
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• 2022

This paper presents a two-stage spatio-spectral fusion method (2SSFM) based on area-to-point regression kriging (ATPRK) to enhance spatial and spectral resolutions using multi-sensor satellite images with complementary spatial and spectral resolutions. 2SSFM combines ATPRK and random forest regression to predict spectral bands at high spatial resolution from multi-sensor satellite images. In the first stage, ATPRK-based spatial down scaling is performed to reduce the differences in spatial resolution between multi-sensor satellite images. In the second stage, regression modeling using random forest is then applied to quantify the relationship of spectral bands between multi-sensor satellite images. The prediction performance of 2SSFM was evaluated through a case study of the generation of red-edge and short-wave infrared bands. The red-edge and short-wave infrared bands of PlanetScope images were predicted from Sentinel-2 images using 2SSFM. From the case study, 2SSFM could generate red-edge and short-wave infrared bands with improved spatial resolution and similar spectral patterns to the actual spectral bands, which confirms the feasibility of 2SSFM for the generation of spectral bands not provided in high spatial resolution satellite images. Thus, 2SSFM can be applied to generate various spectral indices using the predicted spectral bands that are actually unavailable but effective for environmental monitoring.

• Journal of the Microelectronics and Packaging Society
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• v.27 no.2
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• pp.1-10
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• 2020

The technology and market size of image sensors continue to develop thanks to the release of image sensors that exceed 100 million pixels in 2019 and expansion of black box camera markets for vehicles in addition to existing mobile applications. We review the technology flow of image sensors that have been constantly evolving for 40 years since Hitachi launched a 200,000-pixel image sensor in 1979. Although CCD has made inroads into image sensor market for a while based on good picture quality, CMOS image sensor (CIS) with active pixels has made inroads into the market as semiconductor technology continues to develop, since the electrons generated by the incident light are converted to the electric signals in the pixel, and the power consumption is low. CIS image sensors with superior characteristics such as high resolution, high sensitivity, low power consumption, low noise and vivid color continue to be released as the new technologies are incorporated. At present, new types of structures such as Backside Illumination and Isolation Cell have been adopted, with better sensitivity and high S/N ratio. In the future, new photoconductive materials are expected to be adopted as a light absorption part in place of the pn junction.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1366-1370
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• 2010

This paper supposes the vector control algorithm to estimate the rotor position of permanent magnet synchronous traction motor using the hall-effect sensor. The hall-effect provides 60 electrical degrees resolution in rotor position sensing and it is very low resolution. The algorithm makes resolution high as optical encoders or electromagnetic resolver. If necessary, the reference rotor position angle is controlled by adjusting the variable. When a rotor position sensor such as either a optical encoder or a electromagnetic resolver is misalignment, it is useful to align with those. The method on adjusting the reference rotor position angle can compensate for misalignment error degrees by 60 electrical degrees.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.5
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• pp.523-529
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• 2009

Smart sensor is known as intelligent sensor, it is different with other conventional sensors in the case of intelligent system embedded on it. Smart sensor has many benefits e.g. low-cost in usage, self-decision and self-diagnosis abilities. This sensor consists of perception element(sensing element), signal processing and technology of communication. In this work, a bridge and structure of smart sensor has been investigated to be capable to condition monitoring routine. This investigation involves low power consumption, software programming, fast data acquisition ability, and authoritativeness warranty. Moreover, this work also develops smart sensor to be capable to perform high sampling rate, high resolution of ADC, high memory capacity, and good communication for data transfer. The result shows that the developed smart sensor is promising to be applied to various industrial fields.

• Agricultural and Biosystems Engineering
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• v.5 no.1
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• pp.10-20
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• 2004

Precision agriculture aims to minimize costs and environmental damage caused by agriculture and to maximize crop yield and profitability, based on information collected at within-field locations. In this process, quantification of soil physical properties, including soil strength, would be useful. To quantify and manage variability in soil strength, there is need for a strength sensor that can take measurements continuously while traveling across the field. In this paper, preliminary analyses were conducted using two datasets available with current technology, (1) cone penetrometer readings collected at different compaction levels and for different soil textures and (2) tillage draft (TD) collected from an entire field. The objective was to provide information useful for design of an on-the-go soil strength profile sensor and for interpretation of sensor test results. Analysis of cone index (CI) profiles led to the selection of a 0.5-m design sensing depth, 10-MPa maximum expected soil strength, and 0.1-MPa sensing resolution. Compaction level, depth, texture, and water content of the soil all affected CI. The effects of these interacting factors on data obtained with the soil strength sensor should be investigated through experiments. Spatial analyses of CI and TD indicated that the on-the-go soil strength sensor should acquire high spatial-resolution, high-frequency ($\ge$ 4 Hz) measurements to capture within-field spatial variability.

• Journal of Biomedical Engineering Research
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• v.10 no.3
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• pp.293-302
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• 1989

A Dual Sensor Wiener Filter technique was used to improve the image quality of the scanning type digital radiographic system (resolution and SNR). In this method, two images were acquried simultaneously using two sensors with high and low resolution and SNR values. Using the cross Power spectrum between dual sensor outputs of the same chest radiographic image. we design a new type of Wiener Filter and implement it with fast algorithm. We compared the performance of this new dual sensor filter with conventional single sensor filters (Wiener Filter and Parametric Projec- tion Filter) . In simulation studies, it is shown that this new method has SNR improvement of 1-3 dB better than conventional filters.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.145-148
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• 2007

The Korea Multi-Purpose Satellite-2 (KOMPSAT-2) was launched in July 2006 and The main mission of the KOMPSAT-2 is a high resolution imaging for the cartography of Korea peninsula by utilizing Multi Spectral Camera (MSC) images. The camera resolutions are 1 m in panchromatic scene and 4 m in multi-spectral imaging. KOMPSAT-2 measure the position, velocity and attitude data of satellite using by star sensor, gyro sensor, and GPS sensor. This paper provides an initial geometric accuracy assessment of the KOMPSAT-2 high resolution image, both geometric Cal/Val overview.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1445-1462
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• 2022

Compact Advanced Satellite 500-4 (CAS500-4), which is scheduled to be launched in 2025, is a mid-resolution satellite with a 5 m resolution developed for wide-area agriculture and forest observation. To utilize satellite images, it is important to establish a precision sensor model and establish accurate geometric information. Previous research reported that a precision sensor model could be automatically established through the process of matching ground control point (GCP) chips and satellite images. Therefore, to improve the geometric accuracy of satellite images, it is necessary to improve the GCP chip matching performance. This paper proposes an improved GCP chip matching scheme for improved precision sensor modeling of mid-resolution satellite images. When using high-resolution GCP chips for matching against mid-resolution satellite images, there are two major issues: handling the resolution difference between GCP chips and satellite images and finding the optimal quantity of GCP chips. To solve these issues, this study compared and analyzed chip matching performances according to various satellite image upsampling factors and various number of chips. RapidEye images with a resolution of 5m were used as mid-resolution satellite images. GCP chips were prepared from aerial orthographic images with a resolution of 0.25 m and satellite orthogonal images with a resolution of 0.5 m. Accuracy analysis was performed using manually extracted reference points. Experiment results show that upsampling factor of two and three significantly improved sensor model accuracy. They also show that the accuracy was maintained with reduced number of GCP chips of around 100. The results of the study confirmed the possibility of applying high-resolution GCP chips for automated precision sensor modeling of mid-resolution satellite images with improved accuracy. It is expected that the results of this study can be used to establish a precise sensor model for CAS500-4.