Self-Calibrating Triangulation of Airborne Linear Array CCD Cameras (original) (raw)
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Sensor Modeling for Aerial Triangulation with Three-Line-Scanner (TLS) Imagery
Photogrammetrie - Fernerkundung - Geoinformation
This article describes the sensor modeling and the photogrammetric triangulation procedure for the TLS (Three-Line-Scanner) system. This system is a new airborne digital sensor, developed by STARLABO Corporation, Tokyo jointly with the Institute of Industrial Science, University of Tokyo. It utilizes the Three-Line-Scanner principle to capture digital image triplets in along-strip mode. The imaging system contains three times three (RGB) one-dimensional CCD arrays, with 10 200 pixels of 7µm each, mounted parallel to each other in the focal plane. They produce seamless high-resolution images (5-10 cm footprint on the ground) with three viewing directions (forward, nadir and backward). In order to get precise attitude data and high quality image data from an aerial platform, a high quality stabilizer stabilizes the camera and outputs attitude data at 500 Hz. A Trimble MS750 serves as Rover GPS and collects L1/L2 kinematic data at 5 Hz and another Trimble MS750 serves as Base GPS on the ground. The position and attitude elements measured by the on-board GPS/INS do not refer to the perspective center of the imaging camera. Additionally, there is a boresight misalignment between the axes of the INS and the camera. These translational and rotational offsets have been taken into account in our sensor model and triangulation procedures. In our experiments, the following 3 trajectory model are evaluated: (a) Direct georeferencing with stochastic exterior orientations (DGR), (b) Piecewise Polynomials with kinematic model up to second order and stochastic first and second order constraints (PPM) and (c) Lagrange Polynomials with variable orientation fixes (LIM). With different numbers and distributions of control points and tie points, 4.9-6.3 cm and 8.6-9.4 cm absolute accuracy in planimetry and height is achieved using the DGR model under the condition that the GPS/camera displacement corrections have been applied. Moreover, with different numbers of spline sections or orientation fixes, 2.6-6.0 cm and 4.9-11.7 cm absolute accuracy in planimetry and height is attained using the PPM and LIM models. These results show that a ground point determination of 0.5-1.2 pixel accuracy in planimetry and 0.7-2.1 pixel accuracy in height has been achieved. The orientation parameter determination using the DGR model has the advantage of stability and needs less control points, but the obtained accuracy is better with the PPM and LIM models. This however is penalized by the need to have more well-distributed control and tie points. Photogrammetrie, Fernerkundung, Geoinformation, 2003/2, pp. 85-98.
Sensor Integration And Calibration Of Digital Airborne Three-Line Camera Systems
The determination of the exterior orientation parameters is an essential pre-requisite for the evaluation of any imagery from terrestrial, airborne or satellite based sensors. Normally, this georeferencing processing is solved indirectly by using a number of well known ground control points and their corresponding image coordinates. Using a mathematical model for the relation between image and object space the exterior orientations can be calculated and the local image coordinates are related to the global ground coordinate system. In principle this approach can be applied for georeferencing of push-broom line scanner imagery, but this process is highly inefficient. Due to the large number of unknowns a large number of tie and control points is necessary for orientation determination. To allow an operational processing the direct measurement of exterior orientation using GPS and INS and additional information is inevitable. Within this article the geometric processing of high resolu...
The registration and geometric rectification of airborne scanner imagery is a prerequisite for the processing and analysis of this type of images. Within the paper the geometric processing of scanner imagery acquired from the Digital Photogrammetric Assembly (DPA), which is an airborne camera consisting of three pan--chromatic line arrays for stereo imaging and four line arrays for multi--spectral imaging will be described. The sensor system is completed by a module consisting of a differential GPS receiver configuration and an Inertial Navigation System (INS). Within the paper the georeferencing by an integrated GPS/INS component in combination with an aerial triangulation based on the three--line principle of the camera is presented. Additionally, the generation of DTM and ortho images from this type of imagery is demonstrated. 1 INTRODUCTION Up to now digital full frame cameras with an image format comparable to conventional analog photogrammetric cameras do not exist. Alternativ...
FPGA-Based On-Board Geometric Calibration for Linear CCD Array Sensors
Sensors (Basel, Switzerland), 2018
With increasing demands in real-time or near real-time remotely sensed imagery applications in such as military deployments, quick response to terrorist attacks and disaster rescue, the on-board geometric calibration problem has attracted the attention of many scientists in recent years. This paper presents an on-board geometric calibration method for linear CCD sensor arrays using FPGA chips. The proposed method mainly consists of four modules-Input Data, Coefficient Calculation, Adjustment Computation and Comparison-in which the parallel computations for building the observation equations and least squares adjustment, are implemented using FPGA chips, for which a decomposed matrix inversion method is presented. A Xilinx Virtex-7 FPGA VC707 chip is selected and the MOMS-2P data used for inflight geometric calibration from DLR (Köln, Germany), are employed for validation and analysis. The experimental results demonstrated that: (1) When the widths of floating-point data from 44-bit ...
Block Triangulation using Three-line Images
1995
The most advanced camera concept makes use of 3 linear CCD arrays. Stereo images are acquired quasi simultaneously while the camera platform is moving. The mathematical model of photogrammetric point determination is based on a polynomial approach in case of airborne imagery, whereas orbital constraints should be utilized in case of spaceborne imagery. Computer simulations on point determination have turned out that the most accurate results can be obtained by simultaneous block adjustment of multiple overlapping and additional crossing strips. The usefulness of the 3-line camera concept and the applicability of the proposed mathematical models of point determination have been proven with practical airborne MEOSS and spaceborne MOMS-02 imagery. For both MEOSS and MOMS-02 imagery, empirical accuracies in object space of 1 pixel or better in planimetry and height were obtained as verified by independent check points. 1. THREE-LINE CAMERAS
Robust plane-based calibration for linear cameras
2017 IEEE International Conference on Image Processing (ICIP), 2017
A linear, or 1D, camera is a type of camera that sweeps a linear sensor array over the scene, rather than capturing the scene using a single impression on a 2D sensor array. They are often used in satellite imagery, industrial inspection, or hyperspectral imaging. In satellite imaging calibration is often done through a collection of ground points for which the 3D locations are known. In other applications, e.g. hyperspectral imaging, such known points are not available and annotating many different points is onerous. Hence we will use a checkerboard for calibration. The state-of-the-art method for linear camera calibration with a checkerboard becomes unstable when the checkerboards are parallel to the image plane. Our proposed method 1 yields more accurate camera calibrations without suffering from this shortcoming.
Calibration Of Directly Measured Position And Attitude By Aerotriangulation Of Three-Line Airborne
The registration and geometric rectification of airborne scanner imagery is a prerequisite for the processing and analysis of this type of images. Within the paper the geometric processing of scanner imagery acquired from the Digital Photogrammetric Assembly (DPA), which is an airborne camera consisting of three pan--chromatic line arrays for stereo imaging and four line arrays for multi--spectral imaging will be described. The sensor system is completed by a module consisting of a differential GPS receiver configuration and an Inertial Navigation System (INS). Within the paper the georeferencing by an integrated GPS/INS component in combination with an aerial triangulation based on the three--line principle of the camera is presented. Additionally, the generation of DTM and ortho images from this type of imagery is demonstrated.
Processing of 3-line imagery on a digital photogrammetric workstation
1997
One of the main topics in photogrammetry is the development of automatic processing techniques, e.g. for aerotriangulation and stereo restitution, both starting from digital aerial imagery. On the other hand digital cameras and sensors gain more and more importance. One of the most promising sensor concept makes use of three linear CCD arrays. This paper deals with the special geometry of 3-line imagery and the consequences for the processing on a digital photogrammetric workstation.
Operational Use and Empirical Results of Automatic Aerial Triangulation
1995
Aerial triangulation isn't only a major photogrammetric task but it also provides the exterior orientation for aerial photographs. Therefore it is generally required for the most other photogrammetric tasks. In the last time the automation of aerial triangulation with the help of digital techniques has reached an operational level. This paper describes a software system for automatic aerial triangulation. Pilot projects of conventional photogrammetric blocks and digital imagery from 3-line CCD cameras are already processed with this software.