• Journal of Korean Society for Geospatial Information Science
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• v.10 no.2 s.20
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• pp.49-56
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• 2002

Many users of 3D virtual city are Utilize a texture image for the cognition of real object. In this study, building's facet images were achieved by a digital camera and adjusted its distortion by use of the 2D projective transformation method. After then, Images are mapped to a 3D building model by means of the OpenGL. Application program is able to offer an automation solution to construction process of the 3D virtual city.

• Korean Journal of Remote Sensing
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• v.30 no.1
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• pp.75-81
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• 2014

Until recently, photogrammetric applications for processing the satellite images and remotely sensed data have been used in different structure of functions and interfaces for sensor modeling by each developer. Thus, a standardized utilization procedure was necessary to solve the problems, such as expandability, cost, inefficiency of sources which were resulted from different approaches. Therefore, National Geospatial Intelligence Agency (NGA) provided unified interfaces by developing Community Sensor Model (CSM) to sensor models in same way. In this study, we suggested the method of design and analyzed main functions needed modeling for the frame sensor using CSM Application Program Interface (API) provided by NGA. We also applied the designed structure to the modeling. The implemented CSM was verified by groundToImage and imageToGround. In the future, the active R&D is expected with using CSM due to the cost saving effect of software development and remarkable expandability of sensor.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.4
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• pp.55-63
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• 2011

Having a wide angle of view, a fisheye lens is useful for obtaining images of the inside wall of a tunnel. A circular fisheye tunnel image can be transformed into a familiar rectangular image by applying the concept of cylindrical projection. This projection transformation causes several types of distortions in the projected image. This paper discusses the distortion on the boundary lines between smoothly curved wall and flat ground. We analyzed the cause of this boundary distortion, developed transformation model, and derived a correction formular. A distortion correction software programmed in Visual C++ applied to projected image. Consequently, boundary-corrected image could be obtained. Research into other distortions of projected image will helpful in obtaining tunnel image that resembles real tunnel from fisheye tunnel image.

• Journal of Korean Society for Geospatial Information Science
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• v.8 no.2 s.16
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• pp.89-99
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• 2000

The Quality and Accuracy of digital image is important factor for decision of accuracy in digital photogrammetry because all the inside works in digital photogrammetry are based on digital image. But it is still difficult to ensure quality assurance and appication of data because there is no distinct criterion about quality and accuracy of digital image when the works in digital photogrammetry is accomplished. This study presents optimal resolution of aerial photo through error analysis of image coordinate using auto inner orientation in digital photograrnrnetry workstation. In second step, we are valified to optimum resolution of aerial photo image with orientation analysis. Finally, we are established to validity optimal resolution of aerial photo image with production of ortho image and mosaic image using optimal resolution aerial photo image.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.1 s.6
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• pp.67-73
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• 1996

The objective of this research is to investigate the behavior of the $F\"{o}rstner$ interest operator, which has been widely used for detecting distinct points in the field of digital photogrammetry and computer vision, in scale space. Considering the hugh volume of digital image utilized in digital photogrammetry, the scale space (image pyramid) approach which appears to be a solution for enhancing image processing, began to gain its attention. The investigation of the $F\"{o}rstner$ interest operator in scale space generated by the Gaussian kernel shows its behavior and feasibility for being used in practice.

• Journal of Korean Society for Geospatial Information Science
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• v.14 no.1 s.35
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• pp.21-27
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• 2006

Among various image fusion methods, intensity-hue-saturation(IHS) technique is capable of quickly merging the massive volumes of data. For IKONOS imagery, IHS can yield satisfactory 'spatial' enhancement but may introduce 'spectral' distortion, appearing as a change in colors between compositions of resampled and fused multispectral bands. To solve this problem a fast IHS fusion technique with spectral adjustment is presented. The experimental results demonstrate that the proposed approach can provide better performance than the conventional IHS method, in both processing speed and image quality.

• Korean Journal of Remote Sensing
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• v.35 no.6_1
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• pp.945-957
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• 2019

In this study, we propose a coarse to fine image registration method for eliminating geometric error between images over agricultural areas acquired using Unmanned Aerial Vehicle (UAV). First, images of agricultural area were acquired using UAV, and then orthophotos were generated. In order to reduce the probability of extracting outliers that cause errors during image registration, the region of interest is selected by using the metadata of the generated orthophotos to minimize the search area. The coarse image registration was performed based on the extracted tie-points using the Speeded-Up Robust Features (SURF) method to eliminate geometric error between orthophotos. Subsequently, the fine image registration was performed using tie-points extracted through the Mutual Information (MI) method, which can extract the tie-points effectively even if there is no outstanding spatial properties or structure in the image. To verify the effectiveness and superiority of the proposed method, a comparison analysis using 8 orthophotos was performed with the results of image registration using the SURF method and the MI method individually. As a result, we confirmed that the proposed method can effectively eliminated the geometric errors between the orthophotos.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.2 s.8
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• pp.47-54
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• 1996

It needs more than two images which are obtained in real time to decide 3D positioning of dynamic object. Though we use digital camera which is became wide utilization, but it can't obtain sequential image. So, in this study, we constructed momentary image acquisition system using video camera. Also, we took a photograph of LCD timer and dynamic object together for real time stereo image, and we obtained independent digital image from sequential image using video editor. As a result of the study, we could obtain the independent image as true color digital image of $788{\times}550$pixels with 1/100sec accuracy in the same time. And it was good when we tested object target. For comparing 3D positioning accuracy, we could obtained negative with metric camera using B-shutter.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.587-593
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• 2019

The field of geospatial information is rapidly changing due to the development of sensor and data processing technology that can acquire location information. And demand is increasing in various related industries and social activities. The construction and utilization of three dimensional geospatial information that is easy to understand and easy to understand can be an essential element to improve the quality and reliability of related services. In recent years, 3D laser scanners are widely used as 3D geospatial information construction technology. However, 3D laser scanners may cause shadow areas where data acquisition is not possible when objects are large in size or complex in shape. In this study, 3D model of an object has been created by acquiring oblique images using an unmanned aerial vehicle and processing the data. The study area was selected, oblique images were acquired using an unmanned aerial vehicle, and point cloud type 3D model with 0.02 m spacing was created through data processing. The accuracy of the 3D model was 0.19m and the average was 0.11m. In the future, if accuracy is evaluated according to shooting and data processing methods, and 3D model construction and accuracy evaluation and analysis according to camera types are performed, the accuracy of the 3D model will be improved. In the point cloud type 3D model, Cross section generation, drawing of objects, and so on, it is possible to improve work efficiency of spatial information service and related work.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.6
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• pp.555-562
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• 2021

Recently, in the field of geospatial information construction, unmanned aerial vehicles have been increasingly used because they enable rapid data acquisition and utilization. In this study, photogrammetry was performed using fixed-wing, rotary-wing, and VTOL (Vertical Take-Off and Landing) unmanned aerial vehicles, and geospatial information was constructed using two types of unmanned aerial vehicle LiDAR (Light Detection And Ranging) sensors. In addition, the accuracy was evaluated to present the utility of spatial information constructed through unmanned aerial photogrammetry and LiDAR. As a result of the accuracy evaluation, the orthographic image constructed through unmanned aerial photogrammetry showed accuracy within 2 cm. Considering that the GSD (Ground Sample Distance) of the constructed orthographic image is about 2 cm, the accuracy of the unmanned aerial photogrammetry results is judged to be within the GSD. The spatial information constructed through the unmanned aerial vehicle LiDAR showed accuracy within 6 cm in the height direction, and data on the ground was obtained in the vegetation area. DEM (Digital Elevation Model) using LiDAR data will be able to be used in various ways, such as construction work, urban planning, disaster prevention, and topographic analysis.