ABSTRACT:

Kite aerial photography (KAP) involves large kites for lifting cameras 50-150 m above the ground. Either soft (airfoil) or rigid (delta, rokkaku) kites may be utilized in wind ranging from 10 to 40 km/h. Various film, digital, or video imaging devices are employed in single- or dual-camera rigs for acquiring individual images, multiband photos, or stereopairs. Camera pan, tilt, and shutter are operated by radio control from the ground. Photographs may be obtained in visible and near-infrared portions of the spectrum using different film/filter combinations. Photographs can be taken in any position--vertical, low- and high-oblique, and in any orientation relative to the sun and ground object. Vertical digital KAP typically has pixel resolution of 5-10 cm, and about ½ to 1 hectare ground area is depicted in a single scene.

Kite aerial photography is highly portable and can be operated in almost any situation with an open flying field. A crew of two is sufficient normally, one to fly the kite, the other to operate radio controls and take pictures. Low cost makes this method feasible for routine operation by small organizations, and the method is convenient for frequent photography to document environmental changes. We have utilized kite aerial photography for diverse research and commercial applications including assessment of forests and wetlands, investigations of fluvial and glacial landforms, depiction of multiview-angle reflectance phenomena, and surveys of property and construction sites. KAP has proven valuable for bridging the scale and resolution gap between ground observations and conventional airphotos and satellite images.

KEY WORDS: IKONOS, Sensor, Multispectral, Radiometric, Calibration, Stellar

ABSTRACT:

Radiometric calibration of remote sensing satellites has traditionally been accomplished by means of vicarious ground calibration techniques. These methods employ extensive modelling algorithms to describe the ground reflectance, atmospheric absorption, etc. The agile-body IKONOS satellite has the capability to maneuver the vehicle such that celestial scenes can be imaged. Hence, several radiometrically characterized stellar sources have been imaged, on three separate occasions at one-year intervals. The data has been used to develop a radiometric calibration that simply correlates the detector counts in the imagery to the energy presented at the telescope aperture. While the results do not yet fully agree with vicarious ground calibration techniques, the stellar data is highly repeatable, easily predictable, the collection activities are easily scheduled and repeatable, and the results extremely linear. This method has established excellent long-term stability. It promises future absolute radiometric calibration.

KEY WORDS: SPOT5, Geometric Calibration, In-flight, Commissioning, HRG, HRS

ABSTRACT:

SPOT5 Location model calibration addresses five main issues. The first issue is to get best relative and absolute location performances. It consists of relative orientation calibration for HRG, HRS and stellar location unit reference frames. Such a calibration started in-house, using theodolites; it ends in-flight using GCPs. The second issue is to get a model of THR pairs relative shifts good enough to deliver the best 2.5m sampled image. The first ever, true HRG images have been acquired during satellite design, a few months before launch. Such images contributed to THR processing validation and allowed ground calibration of THR detection lines relative shifts, way before launch. In-flight measures confirmed that such ground measures are reliable. Third issue is to turn HRS stereo pairs parallax in a precise enough altitude estimate. That means that HRS location models have to include an accurate model of objectives distortion. A fourth issue consists of HRG's steering mirror mechanism calibration, in order to get the same location performance, whatever the HRG mirror viewing angle is. Final issue deals with optimisation of time delay between two HRG off nadir images acquisition. Such time delay depends on mirror damping speed. For a given viewing angle, called "Autotest", one can acquire HRG images of a designed pattern located in the focal plane. A straightforward processing of this kind of images indicates if the mirror command can be improved. This new calibration process is available in flight as well as on ground. After the two months commissioning phase, objectives are met: images location models are accurate enough to meet all requirements. Absolute location performances provided by the stellar unit are such that new phenomena, never seen on initial SPOT satellites, appear. Initial results show performances trends that we should be able to model, once confirmed through further images acquisition. We specially think about orbital and/or seasonal effects. Work is still carried on.

KEY WORDS: Galileo, GPS, IMU, INS, attitude determination, trajectory determination, Internet computing, WebTop computing.

ABSTRACT:

Since 1999 the Institute of Geomatics has been involved in research and experimental advanced development in the area of integrated inertial/GPS kinematic positioning, attitude determination and gravity measurement. In this paper, a general description of the related hardware and software systems developed by the Institute is given. The systems deal with inertial/GPS data acquisition and processing. The paper discusses, as well, the current ongoing work on distributing geo-processing systems through the Internet. Considering the remarkable progress in the area of integrated systems for airborne Earth observation made in the last years by commercial integrators, the paper will not describe any particular technical details but the overall concept and the development policies behind the systems.

KEY WORDS: IKONOS, satellite, high resolution, imagery, metric, photogrammetry, algorithms, accuracy.

ABSTRACT:

The ground-to-image relationship of an IKONOS image is described by its nominal RPC camera geometry supplemented with bias and drift parameters. Experimental data shows that the RMS bias is 4-meters and the RMS drift is 50 PPM. Residual errors after bias and drift correction are 0.5 meters RMS. A mathematical model to estimate ground coordinates from block-adjusted imagery is developed. Experimental results for this point measurement process will be presented at the conference.

KEY WORDS: Photogrammetry, Calibration, Camera, Satellite, IKONOS, Accuracy, Geometric, High resolution

ABSTRACT:

Since its launch in September of 1999, the IKONOS satellite has been consistently providing high quality 1-meter panchromatic and 4-meter multispectral images. Accurate interior and exterior orientation enable IKONOS to achieve high geometric accuracy with or without ground control. Exterior orientation is determined by on-board GPS receivers, star trackers, gyros, and interlock angles. Post-processing of GPS data with software incorporating sophisticated filtering and orbital modeling algorithms results in accurate ephemeris. Kalman filtering of gyro and star tracker data results in optimal combination of lower frequency star tracker attitude data exhibiting high absolute accuracy with high frequency gyro data being very accurate over short time intervals. Interlock angles relate the attitude and the camera coordinate systems and have been calibrated both pre-launch and in-flight. Initial interior orientation parameter values were determined by pre-launch measurements and later refined by in-flight calibration. In this paper, we shall first demonstrate the high accuracy of such calibrations based on test range data. Later, we shall quantify the geometric accuracy of the IKONOS camera using large IKONOS stereo image blocks with and without ground control, thus validating the exterior and the interior orientation calibrations.

KEY WORDS: Algorithms, Bathymetry, Compression, Digitization, Laser scanning, LIDAR, Mapping

ABSTRACT:

Current discussions in lidar technology often focus on the ability to report multiple returns from each laser pulse. For example, three or more data parameters can be reported from a single pulse (e.g., ranges and intensity). Lidar systems capable of reporting five or more returns are now commercially available. This presentation however, takes the position that merely increasing the number of pulse returns is of limited, and even questionable utility. Instead, an entirely different approach is presented: Waveform Digitization, a technology with far greater potential to add value to the information in the lidar data set. Full waveform analysis has clear advantages over a multiple return approach. The laser pulse's waveform reveals useful information for classifying the surface target. A pulse reflecting off a vertical wall, for example, shows an extended waveform caused by the elliptical "footprint" of the laser spot. From this waveform "signature," the angle of the reflecting surface with respect to the laser beam can be inferred. Waveform characteristics such as "stretching" and "flattening" reveal surface qualities of roughness and smoothness. Multi-peaks and bottoms indicate target characteristics such as density and shape complexity, aiding in point classification. As far back as 1984 Optech Incorporated introduced a bathymetric lidar system with waveform digitization that extracted bottom surface classification information based on the amplitude of bottom returns. Waveform digitization in the Scanning Hydrographic Operational Airborne Lidar Survey (SHOALS) enables it to identify fish, plankton, algae, turbid materials, etc. Flying at altitudes of 200 - 400 m, SHOALS can locate a bottom elevation to within 25 cm (1.... ) accuracy. This degree of accuracy is all the more striking when the phenomenon of backscatter in the water column is considered. What SHOALS demonstrates in water is directly applicable to terrain mapping because it proves that the elevation of the target of interest can be accurately measured even in the presence of ground fog. Waveform digitization however, produces voluminous data. To avoid exceeding storage capacity an Intelligent Waveform Digitizer (IWD) is proposed. Based on intelligent algorithms for lossless data compression the IWD stores data only from "trigger event" to "event end." Unlike a general purpose digitizer which operates indiscriminately, the IWD stores data only from the area of interest. In a forest survey, for example, the IWD stores forest data only, discarding redundant zeroes from non-forest targets. Technical limitations also make it difficult for indiscriminate waveform digitizers to operate at the frequencies common among today's laser systems (...50 kHz). Building upon the success of waveform digitization used in its bathymetric lidar systems, Optech Incorporated proposes to offer IWD in all its lidar systems.

KEY WORDS: Straight line, Self-Calibration, Bundle Adjustment and Digital Cameras

ABSTRACT:

Recent developments of digital cameras in terms of size of Charged Coupled Device (CCD) arrays and reduced costs are leading to their applications to traditional as well as new photogrammetric, surveying, and mapping functions. Digital cameras, intended to replace the conventional film based mapping cameras, are becoming available along with many smaller format digital cameras capable of precise measurement applications. All such cameras require careful assessment to determine their metric characteristics, which are essential to carry out photogrammetric activities. These characteristics include estimates of the calibrated focal length, location of the principal point relative to the array coordinate system, lens distortion, and the short and long-term stability of these quantities. These characteristics are known collectively as the Interior Orientation Parameters (IOP). Current calibration methods are based on traditional test fields with numerous distinct targets, which have to be professionally surveyed prior to the calibration procedure in order to precisely determine their three-dimensional coordinates. Establishing, surveying, and maintaining traditional calibration test fields are very expensive and not easy tasks for non-photogrammetric users of digital cameras. This paper relates to the development of a new laboratory calibration procedure that requires an easy-to-establish calibration test field (group of straight lines). In addition, the whole calibration process can be automatically carried out with minimal human interaction. It is expected that this calibration procedure would provide a good tool for studying the short and long-term stability of off-the-shelf digital cameras. In addition, it will give a great push to using those cameras in large scale mapping applications as well as various close range photogrammetric activities.

KEY WORDS: high-resolution satellite imagery, Ikonos Geo imagery, sensor orientation, high-accuracy geopositioning

ABSTRACT:

An investigation into the use of alternative sensor orientation models and their applicability for block adjustment of high-resolution satellite imagery is reported. Ikonos Geo imagery has been employed in the investigation, and since the explicit camera model and precise exterior orientation information required to apply conventional collinearity-based models is not provided with Ikonos data, alternative sensor orientation models are needed. The orientation models considered here are bias-corrected rational functions (with vendor-supplied rational polynomial coefficients) and the affine projection model. Test results arising from the application of the alternative image orientation/triangulation models within two multi-strip, stereo blocks of Geo imagery are reported. These results confirm that Geo imagery can yield three-dimensional geopositioning to pixel and even sub-pixel accuracy over areas of coverage extending well beyond the nominal single scene area for Ikonos. The accuracy achieved is not only consistent with expectations for rigorous sensor orientation models, but is also readily attainable in practice with only a small number of high-quality ground control points.

KEYWORDS:

ABSTRACT:

Only few space images do have a perspective geometry like aerial cameras. But also the Russian perspective photos do have not negligible systematic image errors. By this reason special mathematical models have to be used for a correct handling of the space images. Polynomial models, often used for remote sensing purposes, are no economic solutions because they do mix the influence of the sensor geometry with the influence of the object elevation and require a high number of control points and do have problems with the identifications of blunders. Different mathematical models have to be used for the correct handling of perspective images together with the identification of systematic image errors, the handling of panoramic cameras like CORONA and KFA 1000, for satellite line scanner cameras and rectification derived from satellite line scanner cameras like the IKONOS Geo-images.

The different mathematical models are explained together with achieved results and problems of the sensors. The solution for the upgrade of IKONOS Geo-images based on a DEM and control points without using rational functions from SpaceImaging (SI) is described. The achieved results are better than specified by SI for the CARTERRA Precision plus.

KEYWORDS:

ABSTRACT:

The determination of the exterior orientation by a combination of an inertial measurement system (IMU) with relative kinematic GPS-positioning - the direct georeferencing - has a growing number of applications for standard photogrammetric projects. One mayor problem is the determination of the relation between the camera and the IMU - the boresight misalignment. The rigorous mathematical model requires the computation and use of it in an orthogonal coordinate system like a tangential system in relation to the earth ellipsoid. But the final data acquisition usually shall be made directly in the national coordinate system. The procedure to use the boresight misalignment without loss of accuracy in the national coordinate system in any location will be explained. Results of the stability of the misalignment over the time will be shown.

If the results of the boresight calibration shall be used for different image scales, also the inner orientation has to be determined together with the boresight misalignment. This has to be done with 2 different flying heights over a calibration site. Another problem is the limited accuracy of the model set up, today the direct sensor orientation is often not accurate enough to guarantee a model set up without a disturbing size of the y-parallaxes. This can be solved with a combined adjustment of the direct sensor orientation together with image coordinates of tie points, but without control points.

KEY WORDS: Calibration, Geometric, Global, Mapping, Orthorectification, Photogrammetry

ABSTRACT:

In order to facilitate a unique georectification approach implemented for Multi-angle Imaging SpectroRadiometer (MISR) data, a specific calibration datasets need to be derived during flight. In the case of the spaceborne MISR instrument with its unique configuration of nine fixed pushbroom cameras, continuous and autonomous coregistration and geolocation of image data are required prior to application of scientific retrieval algorithm. In-flight generated calibration datasets are required to: a) assure accuracy, b) reduce processing load, and c) support autonomous aspect of the processing algorithm. The Camera Geometric Model (CGM) is the first in-flight generated calibration dataset. It is designed to deal with the static pointing errors. However, calibrated CGM is not sufficient to constantly reach required accuracy and provide means for an on-line georectification quality assessment Therefore an off-line geometric accuracy assessment is implemented and will be operated until all of the required calibration datasets are generated and utilized. An overview of the in-flight geometric calibrations and quality assessment along with the current status and discussion of the operational results is presented.

KEY WORDS: Digital Aerial Camera, Aerial Film Camera, Color Sensing, Film Scanning

ABSTRACT:

Aerial film cameras are highly standardized measuring systems. The race is on to find a digital successor applicable as a photogrammetric measuring device with clear advantages over film, meeting accepted standards, covering a large field-of-view, maximizing the geometric resolution of terrain surface detail, minimizing the number of flight lines. Some of today's digital cameras have a small format at a relatively low resolution for special applications. High expectations are associated with the ADS40 by Leica Geosystems (Leica, 2002) using multiple linear arrays in a push-broom mode in analogy to multi-spectral satellite remote sensing systems. Finally there exists the DMC by Z/I Inc. with multiple square arrays CCDs which are assembled into a large "virtual image" as explained by Z/I Inc (2002). We argue that these digital camera concepts are not replacing the existing film cameras. They have limitations as "photogrammetric measuring sensors" and they require a workflow that deviates from the established photogrammetric processes. We argue that the desired digital aerial camera will produce metric imagery as if it had been obtained from a traditional film camera and photogrammetric precision scanner, but at advantageous radiometric performance, advantages in the image acquisition and without the cost of film or film scanning.

KEY WORDS: Digital, Photogrammetry, Calibration, Accuracy, Orthoimage

ABSTRACT:

Space Imaging's Digital Airborne Imaging System (DAIS-1™) is a 12-bit multispectral imaging platform for the generation of orthomosaics at ground sample distances ranging from 0.3 to 2 meters. At the core of the system is a custom-built four-camera assembly utilizing narrow field-of-view sensors, with exterior orientation parameters provided by an onboard GPS/IMU navigation platform. Because all data collection is digital and no ground control is needed, seamless orthomosaics suitable for 1:4800 base mapping and land cover classification are generated within a very short time of overflight. Before the system was brought online, rigorous calibration procedures were required to ensure geometric accuracy and radiometric balancing of the final image product. This paper describes the DAIS platform and discusses the laboratory and field calibration required to prepare the system for production of accurate, tonally balanced orthomosaics.

KEY WORDS: Aerial Mapping, Direct Sensor Orientation, Digital, Exterior Orientation, Photogrammetry,

ABSTRACT:

Quality Control (QC) is a critical step in the mapping process when using Applanix POS AV system in the direct georeferencing mode or in the aerotriangulation mode of mapping. Therefore, in this paper, the necessary steps of quality control of direct georeferencing data is presented in some detail. This is presented through Applanix PSOPAC software package using real mapping data sets. First, a brief description of the quality control steps of POS data is introduced. Then a description of the simultaneous use of navigation/imagery data is presented through the DLC TM Concept.

KEY WORDS: orthoimage, direct georeferencing, geometric rectification, airborne and spaceborne line scanner

ABSTRACT:

For high quality direct georeferencing it is important that all geometric parameters influencing the rectification process are taken into account. These parameters are the exterior and interior orientation of the imaging system, the digital terrain model, the boresight misalignment and the mapping coordinate reference system. For airborne scanner images covering an area of only some miles extension simplifying assumptions can be made without noticeable loss of accuracy; e.g. the position and attitude data can be directly related to the geographic reference system. In airborne applications a high precision navigation sensor system (IMU, DGPS) aligned to the scanner system was used to obtain the parameters of the exterior orientation. Orthoimages were generated with 1-2 pixel accuracy from pushbroom and whiskbroom scanner images.

To rectify space imagery it is necessary to use orthogonal coordinate systems (e.g. Local Topocentric Systems) in an intermediate processing step before finally the result are transformed to a map projection system. Orthoimages were produced from images of the German space camera MOMS-2P.

The software package RECTIFY was developed by DLR and serves as a generic geometry processor for data of different sensor types and navigation systems. It supports all well known coordinate- and map projection systems as well as different geodetic datums. Methods and theory underlying the software package and application examples of airborne and spaceborne imagery will be presented.

KEY WORDS: Coastal Zone, Environment, Marine, Multisensor, Mini Satellite, Hyper spectral, Imaging Spectrometer

ABSTRACT:

Recently, applicational and technological studies have been performed by a group of scientists and industry, led by DLR, basing on experiences with ocean-colour sensor MOS-IRS. The result is a new low-cost mission concept with special emphasis on coastal-zone remote sensing, which will be able to fill an imported gap in Earth observation data, i.e. to detect the strongly needed data for a better understanding of the rapid changes of coastal areas and to provide a tool for monitoring catastrophical hazards.

The proposed low-budget mission ECOMON (Regional Ecological Research and Monitoring) will provide visible to the thermal infrared data with relatively high spectral (1.4 nm) and spatial resolution (100 m). The VISŒSWIRŒTIR spectral region will be covered by 16 selectable channels in the visible, four channels in the SWIR, and one in the TIR. The swath width will be 400 km and a off-nadir tilting possibility ensures a high repetition rate of two days (for latitudes > 30°). Using mainly compact off-the-shelf technology and carrying this payload on a mini-satellite can ensure a low-budget mission with adequate performance for coastal zone observation.

KEY WORDS: Orientation, Modelling, GPS/INS, Integration, Triangulation, Three-Line

ABSTRACT:

This paper describes a general model for CCD linear array sensors with along-track stereo viewing. The sensor external orientation, which is different for each image line, is modelled with time-dependent piecewise polynomial functions and integrated in the standard photogrammetric triangulation, resulting in an indirect georeferencing model. The continuity of the functions and their first and second derivatives between adjacent segments is imposed. In case of sensors carried on airplane, the sensor position and attitude observed by GPS/INS instruments are included in the piecewise polynomial functions. Using Ground Control Points (GCPs) and, additionally, Tie Points (TPs), the function parameters and the ground coordinates of the TPs are estimated in a least-squares adjustment.

The model was tested on imagery acquired by TLS and MOMS-02 sensors, which were carried on helicopter and satellite respectively, using different numbers and distributions of GCPs. The Japanese TLS (Three-Line Sensor) scans along-track in 3 directions with a one-lens optical system. The sensor external orientation for each image line was available by GPS/INS instruments, together with 46 GCPs measured in the images. An absolute accuracy of 4-13 cm in planimetry and 6-16 cm in height was achieved (ground pixel size: 10 cm).

MOMS-02 sensor was carried on the Russian MIR station. The stereopairs used for the test were acquired during the Priroda mission in 1997 and had ground resolution of 18m. The preliminary results showed an absolute accuracy of 6.3-9.3 m in planimetry and 3.0-12.3 m in height.

KEY WORDS: Vegetation, Monitoring, Small/micro satellites, Sensor, Multitemporal, Optical, Proposal

ABSTRACT:

Frequent cloud cover over the Amazon region is the greatest limitation to monitor, via optical remote sensing systems, ongoing activities that are threatening the greatest rainforest of the world. Current optical remote sensing satellites do not have sufficient temporal and spatial resolution in order to be used as operational monitoring system. For instance, with the Landsat system it has been possible to cover the entire Brazilian Amazon with 229 cloud free scenes, only once a year. It is of high relevance to have an efficient monitoring system, from space, to assist the management of natural resources and to protect the Amazon environment. The SSR system presents an innovative solution through a small remote sensing satellite placed in a low equatorial orbit, providing synoptic images of the entire Amazon region, several times a day. The SSR will be a 400 kg satellite using the Brazilian multimission platform for small satellites, which is being developed under INPE's coordination and manufactured by the Brazilian industry. The SSR imaging system consists of a VIS/NIR sensor and a MIR sensor. The VIS/NIR sensor is a pushbroom CCD camera with three optical heads and five spectral bands: blue, green, red, NIR and an additional water vapor content band for atmospheric correction purpose. The MIR sensor is a pushbroom camera with two optical heads and one band in the 3.4 - 4.2 mm region. The spatial resolution at nadir should be 40 m for the VIS/NIR bands and 500 m for the MIR band.

KEY WORDS: Small Satellites, Payload, Platforms, Modulation Transfer Function, Pixelcoregistration

ABSTRACT:

The BIRD (Bispectral Infra-Red Detection) is a small satellite mission of the German Aerospace Centre which was succesfully launched in October 2001as piggyback on the Indian PSLV rocket. High technological and scientific performance could be demonstrated under low budget constraints. The satellite is a three-axis stabilised spacecraft with a mass of 92 kg including over 30% of the total mass for the scientific instrumentation. The primary mission objectives are the test of a new generation of infrared array sensors for detection and scientific investigation of High Temperature Events (HTE) such as forest fires and volcanic activities. Together with a VIS/NIR-sensor with stereo capability as a redesign of the MARS-96 mission the diagnostics of vegetation and the discrimination of smoke and water vapor is possible. Due to the highly compact design a strong interaction of interfaces within a small volume leads to special platform technologies mainly driven by optical and thermal requirements.Therefore the calibration of the three image-forming sensors of BIRD in geometrical, radiometrical and spectral way had to be considered from a very early design phase on. The pixelcoregistration of four sensors working in different spectral ranges requires a very complex calibration facility.

KEY WORDS: Mapping, Change Detection, DEM/DTM, Radar, Satellite

ABSTRACT:

The Canadian Space Agency (CSA) is currently involved in the development of active membrane antenna technology for SAR applications. To qualify this new technology, it is proposed to develop a small satellite L-band SAR demonstrator. Such a demonstrator could be placed on the same orbit than the ALOS satellite for a tandem interferometric mission. The paper describes the initial science objectives and mission definition based on the proposed concept.

KEY WORDS: Radiometry, Hyper spectral, Multispectral, Calibration, Spectral, Measurement, Agriculture, Sensor

ABSTRACT:

This paper presents processes and performance for ground-based measurements used by The Boeing Company and RESOURCE21 for vicarious calibration tests of airborne and satellite multispectral and hyperspectral sensors. We highlight our methodology for measuring downwelling irradiance and scene radiance and reflectance from 400 to 2500 nm, and describe in-house enhancements made to commercial spectroradiometry hardware and software, developed over a period of four years, that facilitate data management and interpretation. Results from tests of the measurement protocols are presented. We present our web-based approach to file management and access, data processing, and quality assessment. Finally, "lessons learned" and issues associated with ground truthing for vicarious sensor tests are discussed.

KEY WORDS: Radiometry, Radiometric calibration, Accuracy, Satellite sensor, Aerial sensor

ABSTRACT:

Since the early 1990s, the availability of remote sensing imagery in the solar reflective (400 to 2500 nm) has seen a dramatic increase. Airborne- and satellite-based sensors now cover this spectral range with a variety of spectral resolutions (from the multispectral to hyperspectral) and spatial resolutions ranging from better than 0.3 m for some airborne systems (and better than 1 m for satellite-based sensors) to 1 km. A critical component to the successful use of data from these systems is the pre-flight and in-flight radiometric calibration of the sensors. This paper provides an overview of currently-used calibration approaches for the inflight calibration using terrestrially-based sites. These methods are colloquially known as vicarious calibration and, alternatively referred to as radiance validations. This discussion focuses on reflectance-based and cross-comparison approaches that can be used at a range of spatial and spectral resolutions. An example of the application of the in-flight and pre-flight calibrations is demonstrated showing results from ALI, ASTER, Hyperion, ETM+, Ikonos, and MODIS.

KEY WORDS: GPS, IMU, Direct Sensor Orientation, Integrated Sensor Orientation

ABSTRACT:

During recent years the direct sensor orientation with GPS and IMU has gained popularity. These systems allow the determination of all exterior orientation elements without using ground control points. This technology opens several new applications for photogrammetry and remote sensing. One precondition for direct sensor orientation with GPS and IMU is the correct sensor calibration. The related parameters as well as the relation between the IMU and the aerial camera (boresight misalignment) have to be determined by conventional bundle block adjustment. During this process a camera self calibration (focal length, principal point, additional parameters etc.) may be performed under operational conditions. To achieve the full accuracy potential of direct sensor orientation, the compensation of systematic errors with the correct mathematical model and an optimum number of parameters for sensor calibration is required. A series of tests was conducted and showed the good accuracy potential of direct GPS/IMU sensor orientation. First investigations showed also problems with y-parallaxes of stereo models based on direct sensor orientation.

Future developments in GPS and IMU sensors and data processing may reduce this problem. Just now we do need another save solution. A promising one is the integration of GPS/IMU and (automatic) aerial triangulation (AAT) into bundle block adjustment, also called integrated sensor orientation. This paper presents the sensor calibration based on data from test flights in large image scales. Furthermore it demonstrates the accuracy potential at independent check points in object and in image space for direct and integrated sensor orientation.

KEY WORDS: Photogrammetry, GPS, Navigation, Direct, Sensor, Orientation, DEM

ABSTRACT:

The direct sensor orientation based on the combination of an inertial measurement system (IMU) and relative kinematic GPS-positioning has reached a high accuracy potential. By this reason it can be used not only for the generation of ortho images, but also for the georeferencing of models for the generation of digital elevation models (DEM). With the data set of the test 'Integrated Sensor Orientation' of the European Organization for Experimental Photogrammetric Research (OEEPE), the generation of DEM's has been investigated. The reached ground accuracy is in the range of ~ 10cm for X and Y, and ~ 10 - 20cm for Z is sufficient for several applications. A mayor problem are y-parallaxes appearing in the set up of the models which has been investigated in detail. This can be reduced by a combined adjustment of the image orientations from direct sensor orientation together with image coordinates of tie points, but without control points. The effect of remaining orientation discrepancies to the model orientation and the resulting model deformation was analyzed.

ABSTRACT:

ADS40 is an airborne digital sensor with 3 panchromatic and 4 multispectral (RGB and near infrared) CCD line sensors developed and supplied by the LH Systems, LLC. Each panchromatic sensor is set to collect forward, nadir and backward views, and it is able to acquire the same ground area 3 times at different angles. The exterior orientation parameters are calculated from the direct geocoordinate system that uses GPS, inertial measurement unit (IMU) and photogrammetric bundle adjustment. We conducted a study to estimate the mapping accuracy by utilizing the panchromatic images of ADS40 for the Tsukuba City in Ibaraki Prefecture, Japan. The control and check points, distributed throughout the study area, were used to evaluate the accuracy.

KEY WORDS: Accuracy, Calibration, Camera, Imagery, Multispectral, Radiometric, Targets

ABSTRACT:

We have characterized and calibrated in absolute radiance units (W/m2 sr mm) a four spectral band imaging radiometer for airborne applications. The characterizations consisted of setting the focus and co-aligning the four cameras in the system, setting the sensitivity via an F/number adjustment in each camera, and verifying the linearity versus both integration time and radiance level. The absolute radiance calibration of each camera was then performed with a large aperture integrating sphere whose calibration is traceable to NIST (National Institute of Standards and Technology). The final step was a verification of the calibration by the measurement of the radiance of a solar irradiated target. The camera radiance values were compared to those made with a portable, non-imaging spectroradiometer that had been calibrated at the same time as the imaging radiometer. The results of the calibration verification indicated the presence of a substantial amount of scattered light that did not affect the quality of the images but require correction for accurate radiometric results.

KEYWORDS: digital camera, calibration, verification

ABSTRACT:

The Digital Mapping Camera (DMC) is the well-known new digital aerial camera system of Z/I Imaging. Analogue aerial cameras manufactured by Carl Zeiss have been successfully used around the world for many decades due to their outstanding photogrammetric performance. The DMC will continue this success and uses therefore an optical design based on CCD-matrix sensors to achieve high geometrical resolution and accuracy together with multi-spectral capabilities. It comprises 8 synchronously operating CCD cameras. Four parallel cameras can generate multi-spectral imagery for the acquisition of colour composites. Four panchromatic images from converging cameras are mosaicked digitally to form a single high resolution image with a large ground coverage. The paper describes this key post processing mosaiking procedure to transform the four individual high-resolution panchromatic images into one virtual image, which can be considered being of a normal perspective projection, usable by all existing exploitation systems. Additionally, results of the geometric calibration and a test with DMC flight data are presented.