• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.26 no.4
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• pp.351-357
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• 2008

An aerial multi-looking camera system equips itself with five separate cameras which enables acquiring one vertical image and four oblique images at the same time. This provides diverse information about the site compared to aerial photographs vertically. The geometric relationship of oblique cameras and a vertical camera can be modelled by 6 exterior orientation parameters. Once the relationship between the vertical camera and each oblique camera is determined, the exterior orientation parameters of the oblique images can be calculated by the exterior orientation parameters of the vertical image. In order to examine the exterior orientation of both a vertical camera and each oblique cameras in the multi-looking camera relatively, calibration targets were installed in a lab and 14 images were taken from three image stations by tilting and rotating a non-metric digital camera. The interior orientation parameters of the camera and the exterior orientation parameters of the images were estimated. The exterior orientation parameters of the oblique image with respect to the vertical image were calculated relatively by the exterior orientation parameters of the images and error propagation of the orientation angles and the position of the projection center was examined.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.3
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• pp.369-375
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• 2010

Since multi-view images can be utilized for 3D visualization and surveying as well, a system calibration is an essential procedure. The cameras in the system are mounted to the holder and their locations and attitudes are relatively fixed. Therefore, the locations and the attitudes of the perspective centers of the four oblique looking cameras can be calculated using the location and attitude of the nadir looking camera and the boresight values between the cameras. In this regard, this research is focusing on the analysis of the relative location and attitude between the nadir and oblique looking cameras based on the results of the exterior orientation parameters after the aerial triangulation of the real multiview images. We acquired high standard deviations of the relative locations between the nadir and oblique cameras. Standard deviations of the relative attitudes between the cameras were low when only the exterior orientations of the oblique looking cameras were allowed to be adjusted. Moreover, low standard deviations of the relative attitudes came when we considered not all the exterior orientations of the cameras but the attitudes of them only.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.621-629
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• 2011

According to the development of technologies for generating the 3D spatial information, the needs for producing and updating the precise 3D objects with LoD 4 level are increased. On the other hand, the needs for real-time updating of 2D digital maps are expanded, based on the execution of various GIS projects. These 2D informations can be extracted from precisely constructed 3D spatial information, to do this the feasibility studies on extraction of the 2D information from the 3D spatial information is needed. In this study, 3D objects are modeled using multi-oblique images, and the objects are stereo-plotted using digital airborne images, as well. Then the two data sets are compared and analyzed. The results show that the accuracy assessments fulfill the 1/1,000 digital map accuracy standard of regulations for photogrametric surveying of National Geographic Information Institute, but the shapes and the areas of building objects are different between two data sets because of the portrayal standards. Consequently, researchers can conclude that it is possible to generate the building layer of large scale topographic map using multi-oblique images, but additional researches is needed to resolve the problems on differences of the portrayal standards.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.2
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• pp.261-271
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• 2009

Due to the recent rise of a need for 3 dimensional geospatial information on urban areas, general interest in aerial multi-view cameras has been on an increase. The conventional geospatial information system depends solely upon vertical images, while the multi-view camera is capable of taking both vertical and oblique images taken from multiple directions, thus making it easier for the user to interpret the object. Through our research we developed a prototype of a multi-view camera system that includes a camera system, GPS/INS, a flight management system, and a control system. We also studied and experimented with the camera viewing angles, the synchronization of image capture, the exposure delay, the data storage that must be considered for the development of the multi-view camera system.

• Journal of the Korean Solar Energy Society
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• v.33 no.5
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• pp.51-59
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• 2013

It is usual to evaluate the performance of the cool roof by measuring in-site rooftop temperature using thermal infra-red camera. The principal advantage of rooftop thermal infrared image acquired in oblique vantage point of super high-rise building as a remote sensor is to provide, in a cost-effective manner, area-wide information required for a scattered rooftop target with different colors, utilizing wide view angle and multi-temporal data coverage. This research idea was formulated by incorporating the concept of traditional remote sensing into rooftop temperature monitoring. Correlations between infrared image of super high-rise building and in-situ data were investigated to compare rooftop surface temperature for a total of four different rooftop locations. The results of the correlations analyses indicate that the rooftop surface temperature by the infrared images of super high-rise building alone could be explained yielding $R^2$ values of 0.951. The visible permanent record of the oblique thermal infra-red image was quite useful in better understanding the nature and extent of rooftop color that occurs in sampling points. This thermal infrared image acquired in oblique vantage point of super high-rise made it possible to identify area wide patterns of rooftop temperature change subject to many different colors, which cannot be acquired by traditional in-site field sampling. The infrared image of super high-rise building breaks down the usual concept of field sampling established as a conventional cool roof performance evaluation technique.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.53-56
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• 2010

An aerial multi-looking camera system equips itself with five separate cameras which enables acquiring one vertical image and four oblique images at the same time. This provides diverse information about the site compared to aerial photographs vertically. However, multi-looking Aerial Camera for building a 3D spatial information don't use a large-size CCD camera, do uses a medium-size CCD camera, if acquiring forward, backward, left and right imagery of Certain objects, Aerial photographing set overlap and sidelap must be considered. Especially, Sideward-looking camera set up by the sidelap to determine whether a particular object can be acquisition Through our research we analyzed of sideward footprint and aerial photographing efficiency of Multi-view imagery by sidelap changing.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.3
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• pp.145-154
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• 2014

The road network becomes more complex and extensive. Therefore, the inconveniences are caused in accordance with the time delay of the restoration of damaged roads, demands for excessive costs on information collection, and limitations on acquisition of damage information of the roads. Recently, road centric spatial information is gathered using mobile multi sensor system for road inventory. But expensive MMS(Mobile Mapping System) equipments require high maintenance costs from beginning and takes a lot of time in the data processing. So research is needed for continuous maintenance by collecting and displaying the damaged information on a digital map using low cost mobile camera system. In this research we aim to develop the techniques for mosaic with a regular ground sample distance using successive image from oblique camera on a vehicle. For doing this, mosaic image is generated by estimating the homography of high resolution oblique image, and the ground sample distance and appropriate overlap are analyzed using high resolution aerial oblique images which contain resolution target. Based on this we have proposed the appropriate overlap and exposure interval for mobile road inventory system.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.19-22
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• 2002

A process of 3-D particle image velocimetry, called here, as '3-D stereo PIV' was developed for the measurement of a section field of 3-D complex flows. The present method includes modeling of camera by a calibrator based on the homogeneous coordinate system, transfromation of oblique-angled image to transformed image, identification of 2-D velocity vectors by 2-D cross-correlation equation, stereo matching of 2-D velocity vectors of two cameras, accurate calculation of 3-D velocity vectors by homogeneous coordinate system and finally 3-D animation as the post processing. In principle, as two frame images only are necessary for the single instantaneous analysis of a section field of 3-D flow, more effective vectors are obtainable contrary to the previous multi-frame vector algorithm. An experimental system was also used for the application of the proposed method. Three analog CCD cameras and an Argon-Ion Laser(300mW) for illumination were adopted to capture the wake flow behind a bluff obstacle.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.741-747
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• 2009

For construction of 3D virtual city models, airborne digital cameras, laser scanners, multi-oblique photograph systems and other devices are currently being used. With such advanced techniques, precise 3D spatial information can be collected and high quality 3D city models can be built in a considerably large area. The 3D spatial information to be built has to provide the latest information that quickly reflects the causes of any change due to urban development. In this study, a UAV photogrammetric method using low cost UAV and digital camera was proposed to acquire and update 3D spatial information effectively on small areas where information continuously change. In the proposed UAV photogrammetric method, the elements of interior orientation were acquired through camera calibration and the vertical and oblique photographs were taken at 9 points and the 3D drawing of ground control points and buildings was performed using 20 images among the pictured images. This study also analyzed the accuracy of the proposed method comparing with ground survey data and digital map in order to examine whether the method can be used in on-demand 3D spatial information update on relatively small areas.

• Korean Journal of Remote Sensing
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• v.34 no.6_1
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• pp.941-951
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• 2018

Utilization and demand of UAV (unmanned aerial vehicle) for the generation of 3D city model are increasing. In this study, we performed an experiment to adjustment position/orientation of UAV with incomplete attitude information and to extract point cloud data. In order to correct the attitude of the UAV, the rotation angle was calculated by using the continuous position information of UAV movements. Based on this, the corrected position/orientation information was obtained by applying IBA (Incremental Bundle Adjustment) based on photogrammetry. Each pair was transformed into an epipolar image, and the MDR (Multi-Dimensional Relaxation) technique was applied to obtain high precision DSM. Each extracted pair is aggregated and output in the form of a single point cloud or DSM. Using the DJI inspire1 and Phantom4 images, we can confirm that the point cloud can be extracted which expresses the railing of the building clearly. In the future, research will be conducted on improving the matching performance and establishing sensor models of oblique images. After that, we will continue the image processing technology for the generation of the 3D city model through the study of the extraction of 3D cloud It should be developed.