• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.471-474
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• 2004

Not all CCD pixels generate uniform value for the uniform radiance due to the different process of manufacture and each pixel characteristics. And the image data compression is essential in the real time image transmission because of the high line rate and the limited RF bandwidth. This pixel's nonuniformity and the loss compression make CCD pixel correction necessary in on-orbit condition. In the MSC system, the NUC unit, which is a part of MSC PMU, is charge of the correction for CCD each pixel. The correction is performed with the gain and the offset table for the each pixel and the each TDI mode. These correction tables are generated and programmed in the PMU Flash memory through the various image data tests at the ground test. Besides, they can be uploaded from ground station after onorbit calibration. This paper describes the principle of the table generation and the test way of the non-uniformity after NUC

• Publications of The Korean Astronomical Society
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• v.11 no.1
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• pp.147-161
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• 1996

The development of universal CCD camera control software for all BOAO CCD camera systems is proposed. The new software, running under Sun SPARCstation and motif based X window system with SunOS 4.1.3 operating system, replaces existing control software based on NeXTstation color and NeXTstep 2.1 operating system which is no more produced now. Several new features of the new software is introduced, some of which are 1) the image contrast is enhanced by color manipulation and display, 2) image zooming and trimming, 3) any size of image can be displayed in the scrolled window, and 4) the offset between telescope pointing position and CCD center is easily calculated by alt-azi map. Along with the above new features, the new software has advantages including ease of maintenance and upgrading and elimination of risk caused by hardware damage. Since September 1, the software beta version is being used by observers and there is not seen severe problem regarding the software itself, but several requests to equip more features to the software will be mirrored to future release.

• Proceedings of the KSRS Conference
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• 2007.10a
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• pp.504-507
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• 2007

The KOMPSAT-2 satellite is a push-broom system with MSC (Multi Spectral Camera) which contains a panchromatic band and four multi-spectral bands covering the spectral range from 450nm to 900nm. The PAN band is composed of six CCD array with 2528 pixels. And the MS band has one CCD array with 3792 pixels. Raw imagery generated from a push-broom sensor contains vertical streaks caused by variability in detector response, variability in lens falloff, pixel area, output amplifiers and especially electrical gain and offset. Relative radiometric calibration is necessary to account for the detector-to-detector non-uniformity in this raw imagery. Non-uniformity correction (NUC) is that the process of performing on-board relative correction of gain and offset for each pixel to improve data compressibility and to reduce banding and streaking from aggregation or re-sampling in the imagery. A relative gain and offset are calculated for each detector using scenes from uniform target area such as a large desert, forest, sea. In the NUC of KOMPSAT-2, The NUC table for each pixel are divided as HF NUC (high frequency NUC) and LF NUC (low frequency NUC) to apply to few restricted facts in the operating system ofKOMPSAT-2. This work presents the algorithm and process of NUC table generation and shows the imagery to compare with and without calibration.

• Journal of Biosystems Engineering
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• v.25 no.1
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• pp.55-62
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• 2000

Autonomous farm operation needs to be developed for safety, labor shortage problem, health etc. In this research, an autonomous tractor for tillage was investigated using machine vision and a fuzzy logic controller(FLC). Tractor heading and offset were determined by image processing and a geomagnetic sensor. The FLC took the tractor heading and offset as inputs and generated the steering angle for tractor guidance as output. A color CCD camera was used fro the image processing . The heading and offset were obtained using Hough transform of the G-value color images. 15 fuzzy rules were used for inferencing the tractor steering angle. The tractor was tested in the file and it was proved that the tillage operation could be done autonomously within 20 cm deviation with the machine vision and the FLC.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.40-43
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• 1997

This paper presents a 3D object recognition method for generation of 3D environmental map or obstacle recognition of mobile robots. An active light source projects a stripe pattern of light onto the object surface, while the camera observes the projected pattern from its offset point. The system consists of a laser unit and a camera on a pan/tilt device. The line segment in 2D camera image implies an object surface plane. The scaling, filtering, edge extraction, object extraction and line thinning are used for the enhancement of the light stripe image. We can get faithful depth informations of the object surface from the line segment interpretation. The performance of the proposed method has demonstrated in detail through the experiments for varies type objects. Experimental results show that the method has a good position accuracy, effectively eliminates optical noises in the image, greatly reduces memory requirement, and also greatly cut down the image processing time for the 3D object recognition compared to the conventional object recognition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.8
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• pp.1759-1764
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• 2012

This paper describes FPGA design and realization using the shading correction algorithm for a CCD scan image enhancement. The shading algorithm is used by LUT (Look-up Table). The image enhancement results from that the histogram minimum value and maximum with respect to all pixels of the CCD image should be extracted, and the shading LUT is constructed to keep constant histogram with offset data. The output of sensor be converted to corrected LUT image in preprocessing, and the converting system is realized by FPGA to be enabled to operate in real time. The result of the experimentation for the proposed system is showed to take the scanning time 2.4ms below. The system is presented to be based on a low speed processor system to scan enhanced images in real time and be guaranteed to be low cost.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.591-595
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• 1990

This paper describes a method of aisle following of a mobile robot using machine vision. As a navigation guide, Black strip painted on the lower part of wall of aisle is used. The offset of the vehicle position from the center of aisle and the heading angle are determined from the binary image of guide strip captured by a CCD camera. To remove the effect of noise. i.e. break of guide strip for the door or reflection of light, pixel sampling method together with consistency check of the incline for the sampled pixels is used.

• Journal of Mechanical Science and Technology
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• v.16 no.12
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• pp.1702-1709
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• 2002

This paper analyzes heterogeneous distribution of branch-like structure at the downstream region of the spray. The liquid and vapor phase of the spray are obtained using a 35㎜ still camera and CCD camera in order to investigate spray structure of evaporating diesel spray. There have been many studies conducted on diesel spray structure but have yet only focused on the analyses of 2-D structure. There are a few information which is concerned with 3-D structure analysis of evaporating spray. The heterogeneous distribution of droplets in inner spray affects the mixture formation of diesel spray and the combustion characteristics of the diesel engines. In this study, the laser beam of 2-D plane was used in order to investigate 3-D structure of evaporating spray The incident laser beam was offset on the central axis of the spray. From the analysis of images taken by offset laser beam, we will examine the formation mechanism of heterogeneous distribution of the diesel spray by vortex flow at the downstream of the spray. The images of liquid and vapor phase of free spray are simultaneously taken through an exciplex fluorescence method. Through this, the branch-like structure consisting of heterogeneous distribution of the droplets forms high concentrated vapor phase at the periphery of droplets and at the spray tip.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.604-607
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• 2005

All CCD pixels do not react uniformly even if the light of same radiance enters into the camera. This comes from the different camera optical characteristics, the read-out characteristics, the pixel own characteristics and so on. Usually, the image data of satellite camera can be corrected by the various image-processing methods in the ground. However, sometimes, the in-orbit correction is needed to get the higher quality image. Especially high frequency pixel correction in the middle of in-orbit mission is needed because the in-orbit data compression with the high frequency loss is essential to transmit many data in real time due to the limited RF bandwidth. In this case, this high frequency correction can prevent have to have any unnecessary high frequency loss. This in-orbit correction can be done by the specific correction table, which consists of the gain and the offset correction value for each pixel. So, it is very important to get more accurate correction table for good correction results. This paper shows the new algorithm to get accurate pixel correction table. This algorithm shall be verified theoretically and also verified with the various simulation and the test results.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.25.3-25.3
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• 2009

To search for the quasars at z > 7 in early universe, we are developing a optical camera which has a $1k\times1k$ deep depletion CCD chip, with later planned upgrade to HAWAII-2RG infrared array. We are going to attach the camera to the cassegrain focus of Otto Struve 2.1m telescope at McDonald observatory of University of Texas at Austin, USA. We present the design of a hardware interface to attach the CCD camera to the telescope. It consists of focal reducer, filter wheel, and guiding camera. Focal reducer is needed to reduce the long f-ratio (f/13.7) down to about 4 for wide field of view. The guiding camera design is based on that of DIAFI offset guider which developed for the McDonald 2.7m telescope.