• Journal of Institute of Control, Robotics and Systems
• /
• v.22 no.2
• /
• pp.139-146
• /
• 2016

Recently, popularity of 3D technology has been growing significantly and it has many application parts in the various fields of industry. In order to overcome the limitations of 2D machine vision technologies based on 2D image, we need the 3D measurement technologies. There are many 3D measurement methods as such scanning probe microscope, phase shifting interferometry, confocal scanning microscope, white-light scanning interferometry, and so on. In this paper, we have used the extended depth of focus (EDF) algorithm among 3D measurement methods. The EDF algorithm is the method which extracts the 3D information from 2D images acquired by short range depth camera. In this paper, we propose the EDF algorithm using the edge informations of images and the average values of all pixel on z-axis to improve the performance of conventional method. To verify the performance of the proposed method, we use the various synthetic images made by point spread function(PSF) algorithm. We can correctly make a comparison between the performance of proposed method and conventional one because the depth information of these synthetic images was known. Through the experimental results, the PSNR of the proposed algorithm was improved about 1 ~ 30 dB than conventional method.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.48 no.11
• /
• pp.27-33
• /
• 2011

Recently many display devices support the digital display interface as display market growth. DisplayPort is a next generation display interface at the PC, projector and high definition content applications in more widely used connection solution development. This paper implements multiple streams based on the behavior of the main link that is suitable for the display port v1.1a standard. The limit point of Displayport, interface between the Sink Device and Sink Device is also implemented. And two or more differential image data are enable to output the result through four Lanes stated in display port v1.1a, of two or more display devices without the addition of a separate Lane. The Multiple Video Streaming Controller is implemented with 6,222 ALUTs and 6,686 register, 999,424 of block memory bits synthesized using Quartus II at Altera Audio/Video Development board (Stratix II GX FPGA Chip).

• Smart Structures and Systems
• /
• v.25 no.2
• /
• pp.135-153
• /
• 2020

There has been a sustained interest towards the non-contact structural displacement measurement by means of videogrammetric technique. On the way forward, one of the major concerns is the spurious image drift induced by temperature variation. This study therefore carries out an investigation into the temperature effect of videogrammetric technique, focusing on the exploration of the mechanism behind the temperature effect and the elimination of the temperature-caused measurement error. 2D videogrammetric measurement tests under monotonic or cyclic temperature variation are first performed. Features of measurement error and the casual relationship between temperature variation and measurement error are then studied. The variation of the temperature of digital camera is identified as the main cause of measurement error. An excellent linear relationship between them is revealed. After that, camera parameters are extracted from the mapping between world coordinates and pixels coordinates of the calibration targets. The coordinates of principle point and focal lengths show variations well correlated with temperature variation. The measurement error is thought to be an outcome mainly attributed to the variation of the coordinates of principle point. An approach for eliminating temperature-caused measurement error is finally proposed. Correlation models between camera parameters and temperature are formulated. Thereby, camera parameters under different temperature conditions can be predicted and the camera projective matrix can be updated accordingly. By reconstructing the world coordinates with the updated camera projective matrix, the temperature-caused measurement error is eliminated. A satisfactory performance has been achieved by the proposed approach in eliminating the temperature-caused measurement error.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.9
• /
• pp.1723-1729
• /
• 2016

Digital watermarking is tried to get an optimum tradeoffs between its performance characteristics, robustness, transparency and capacity. This paper is, therefore, suggesting a watermarking technique that builds multiple barcodes in various frequency bands to implement embedded watermarks that is imperceptible and robust against various attacks. Even though a watermark technique with duplicated barcode watermarks embedded in various frequency bands can satisfy robustness as there is high possibility that watermarks embedded in an image remains after various attacks, the duplicated barcode data can weaken imperceptibility. Thus, to satisfy the conflicting characteristic requirements of watermarks, robustness and imperceptibility, different barcode data is embedded in each frequency band. The test shows that ownership authentication with the technique suggested in this thesis does not require specialized hardware, and extracted watermarks can be easily identified through a mobile barcode scanner app, which allows low complexity, low cost and swift identification.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.39 no.2
• /
• pp.7-13
• /
• 2002

When a USB digital camera is used for PC video-conference applications, motion picture data need to be transferred to the PC through the USB port. Due to the mismatch between the data rates of the USB and the motion picture, data compression should be performed before the transmission from the USB. While many motion picture compression algorithms require large intermediate memory space, the JPEG algorithm does not need to store an entire frame for the compression. Instead, a relatively small buffer is required at the input of the JPEG compression engine to resolve the inconsistency between the orders of the inputted data and the consumed data. Data reordering can be easily implemented using a double buffering scheme, which still requires a considerable size of memory. In this paper, a novel memory management scheme is proposed to avoid the double buffering. The proposed memory architecture requires a small amount of memory and a simple address generation scheme, resulting in overall cost reduction.

• Journal of Biomedical Engineering Research
• /
• v.24 no.2
• /
• pp.83-89
• /
• 2003

The gas electron multiplier placed in the drift volume of conventional gas detectors, is a conceptually simple device for producing a large gas gain by concentrating the drift electric field over a very short distance to the point that electron avalanching occurs(〉 10$^4$ V/cm), greatly increasing the number of drifting electrons. This device consists of a thin insulating foil of several tens of urn in thickness. covered on each side with a thin metal layer(Cu), with tiny holes, usually 100 ${\mu}{\textrm}{m}$ or less in diameter. and with a spacing of 100-200 ${\mu}{\textrm}{m}$ through the entire foil. perforated by using chemical etching or high-powered laser beam technique In this study, we have investigated its operating properties with various experimental conditions, and demonstrated the possibility of using this device as a digital X-ray imaging sensor, by acquiring X-ray images based on the scintillation properties of the gas electron multiplier with standard CCD camera.

• Journal of the Korean Geosynthetics Society
• /
• v.5 no.3
• /
• pp.45-52
• /
• 2006

The collapsed cases are more and more increasing at the large scaled structures because of increasing of the risk due to natural disasters. The measuring instrument such as inclinometer, total station on reinforced-soil retaining wall has been used that displacement, settlement for stability assessment, maintenance and management of it. But because these has gotten many instability measuring factors for stability analysis of RRW, new system needs to complement disadvantage of existing system. In this study, we considered a application of Visual Monitoring System (VMS) to measure a displacement in face of wall through Lab. test about block assembly of segmental retaining wall during load test.

• Journal of the Korean Geographical Society
• /
• v.35 no.5
• /
• pp.745-754
• /
• 2000

Both Geographic Information System and Remote Sensing fields have been nearly neglected or ignored by historical geographers.This paper intends to show the potentiality of satellite images of various spatial reslutions to explore and to express themes of historical geography. Old Chinese maps and atlas were also used to relate the digital values and historical facfors. Advanced Very High Resolution Radiometer data might be used as a real image for a contintal scale to show changes in coastal shoreline. Landsat Thematic Mapper Imagery of Beijing showed some of boundaries of old palace. Finally IKONOS images of one meter resolution showed detailed information of landcover and landuse of the City, Beijing. The potential capability and limitation to apply satellite imagery in application of historical geography are also discussed.

• 한국HCI학회:학술대회논문집
• /
• 2008.02a
• /
• pp.697-702
• /
• 2008

Mobile display panel is small so that users are often difficult to perceive images clearly. About image we perceive much through colors and therefore we propose color fitting approach for clear perception even on the small and low quality LCD panels. Various color modifications have been studied and used in commercial software packages. For mobile usage, our approach instantly enhances color images by modifying colors in a way to contrast differences of them. The method includes tone enhancements (which contrast dark and bright sides) and color enhancements (which reduce saturation for pure colorants). Based on color theory, our method also modifies color values towards specified complementary and preference colors. We term this color fitting. This approach enables displaying photos, multimedia messages, videos and digital media broadcasting (DMB) for better perception in real-time on mobile devices. Index Terms.) color fitting, visualization on small display, mobile graphics, visual perception.

• International Journal of Fluid Machinery and Systems
• /
• v.10 no.2
• /
• pp.146-153
• /
• 2017

Sediment flow through hydropower components causes hydro-abrasive erosion resulting in loss of efficiency, interruptions in power production and downtime for repair/maintenance. Online instruments are required to measure/capture the variations in sediment parameters along with collecting samples manually to analyse in laboratory for verification. In this paper, various sediment parameters viz. size, concentration (TSS), shape and mineral composition relevant to hydro-abrasive erosion were measured and discussed with respect to a hydropower plant in Himalayan region, India. A multi-frequency acoustic instrument was installed at a desilting chamber to continuously monitor particle size distribution (PSD) and TSS entering the turbine during 27 May to 6 August 2015. The sediment parameters viz. TSS, size distribution, mineral composition and shape entering the turbine were also measured and analysed, using manual samples collected twice daily from hydropower plant, in laboratory with instruments based on laser diffraction, dynamic digital image processing, gravimetric method, conductivity, scanning electron microscope, X-ray diffraction and turbidity. The acoustic instrument was able to capture the variation in TSS; however, significant deviations were found between measured mean sediment sizes compared to values found in the laboratory. A good relation was found for turbidity ($R^2=0.86$) and laser diffraction ($R^2=0.93$) with TSS, which indicated that turbidimeter and laser diffraction instrument can be used for continuous monitoring of TSS at the plant. Total sediment load passed through penstock during study period was estimated to be 15,500 ton. This study shall be useful for researchers and hydropower managers in measuring/monitoring sediment for hydro-abrasive erosion study in hydropower plants.