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

• Spatial Information Research
• /
• v.10 no.2
• /
• pp.317-329
• /
• 2002

Coastal landforms such as sand beach and coastal sand dune are changing dynamically, and the research about them is being conducted. Conventionally the leveling method has been applied to measuring heights of dynamic morphological surface in coastal landforms. We applied the photograrmmetric method which was not considered to measure the heights on coastal sand dune’s profile to calculating the heights of coastal sand dune; that is, the heights of unknown points on coastal sand dune’s profile was reckoned from the digital photographs’stereo pairs through bundle adjustment and backward transform of collinearity condition equation. we used six GCPs to perform bundle adjustment. After backward transform the error of heights between surveyed value and computed value was estimated around 10cm. In general, the pole is not adamantly fixed on the surface of coastal sand dune because of its softness, and then the disturbance of coastal sand dune adjoining surveyed area can be made in small area. Digital photogrammetry can solve the problem which conventional leveling method has, and be replaced it.

• Journal of Korean Society for Geospatial Information Science
• /
• v.12 no.4 s.31
• /
• pp.61-68
• /
• 2004

In this paper, we suggest an automatic technique to obtain 3-D road information in complex urban areas using road pavement markings. This method is composed of following three main steps. The first step is extracting the pavement markings from aerial images, the second one is matching the same pavement markings in two aerial images, and the last one is obtaining the 3-D coordinates of those using EOP(exterior orientation parameters) of aerial images. Here, we focus on the first and second step because the last step can be performed by using the well hewn collinearity condition equation. We used geometric properties and spatial relationships of the pavement markings to extract the lane line markings on the images and extracted arrow lane markings additionally using template matching. And then, we obtained 3-D coordinates of the road using relational matching for the pavement markings. In order to evaluate the accuracy of extraction, we did a visual inspection and compared the result of this technique with those measured by digital photogrammetric system.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.35 no.6
• /
• pp.553-562
• /
• 2017

GPS (Global Positioning System) receiver among various sensors mounted on UAV (Unmanned Aerial Vehicle) helps to perform various functions such as hovering flight and waypoint flight based on GPS signals. GPS receiver can be used in an environment where GPS signals are smoothly received. However, recently, the use of UAV has been diversifying into various fields such as facility monitoring, delivery service and leisure as UAV's application field has been expended. For this reason, GPS signals may be interrupted by UAV's flight in a shadow area where the GPS signal is limited. Multipath can also include various noises in the signal, while flying in dense areas such as high-rise buildings. In this study, we used analytical photogrammetry and auto tracking total station technique for 3D positioning of UAV. The analytical photogrammetry is based on the bundle adjustment using the collinearity equations, which is the geometric principle of the center projection. The auto tracking total station technique is based on the principle of tracking the 360 degree prism target in units of seconds or less. In both techniques, the target used for positioning the UAV is mounted on top of the UAV and there is a geometric separation in the x, y and z directions between the targets. Data were acquired at different speeds of 0.86m/s, 1.5m/s and 2.4m/s to verify the flight speed of the UAV. Accuracy was evaluated by geometric separation of the target. As a result, there was an error from 1mm to 12.9cm in the x and y directions of the UAV flight. In the z direction with relatively small movement, approximately 7cm error occurred regardless of the flight speed.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.1
• /
• pp.31-43
• /
• 2015

This study had been aimed to conduct the camera calibration on VLBI antenna in the Space Geodetic Observation Center of Sejong City with a low-cost digital camera, which embedded in a mobile phone to determine the three-dimension position coordinates of the VLBI antenna, based on stereo images. The initial values for the camera calibration have been obtained by utilizing the Direct Linear Transformation algorithm and the commercial digital photogrammetry system, PhotoModeler $Scanner^{(R)}$ ver. 6.0, respectively. The accuracy of camera calibration results was compared with that the camera calibration results, acquired by a bundle adjustment with nonlinear collinearity condition equation. Although two methods showed significant differences in the initial value, the final calibration demonstrated the consistent results whichever methods had been performed for obtaining the initial value. Furthermore, those three-dimensional coordinates of feature points of the VLBI antenna were respectively calculated using the camera calibration by the two methods to be compared with the reference coordinates obtained from a total station. In fact, both methods have resulted out a same standard deviation of $X=0.004{\pm}0.010m$, $Y=0.001{\pm}0.015m$, $Z=0.009{\pm}0.017m$, that of showing a high degree of accuracy in centimeters. From the result, we can conclude that a mobile phone camera opens up the way for a variety of image processing studies, such as 3D reconstruction from images captured.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.5 no.2
• /
• pp.109-120
• /
• 1985

This thesis is a study on multiple close range photogrammetry, and the purpose of this study is to develop the most accurate adjustment method of three dimensional object coordinates. This was achieved by comparing the standard errors of actual data to the computed values from 2 photos and multiple photos. The conventional methods for multiple photos have been analyzed by using geometric model formation. But in this study, the equation of collinearity condition which has been applied to aerial photogrammetry was derived to be a basic principle of close range photogrammetry, and the algorithm for analyzing multiple photos was developed using simultaneous bundle adjustment. The method used in this study, showed more homogeneous accuracy in coordinate and more consistent variance of error than those of conventional methods. It was found that the cases using 3, 4, and 5 photos were more accurate than using 2 photos; the accuracies were improved to 15%, 35%, and 50%, for each case. Thus this study is expected to be useful in measuring the geometry of historic monuments and other structures requiring high accuracy. Also the combined case of multiple photos is considered to be effective for the precise analysis of the objects which are difficult to measure for obstacles.