Junichi Takaku

PRISM On-Orbit Geometric Calibration and DSM Performance

The Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) carried by the Advanced Land-Observing Satellite was designed to generate worldwide topographic data with its high-resolution and stereoscopic observation. For this objective, the on-orbit geometric performance of PRISM sensors has been widely assessed and calibrated since the launch in January 2006 as an activity of the calibration and validation team of the Japan Aerospace Exploration Agencys Earth Observation Research Center. This ongoing activity has generated various geometric performance data over two and a half years of on-orbit operation. A suite of geometric model parameters was calibrated to express the geometric characteristics of the PRISM sensors. These include static interior parameters (charge-coupled device camera parameters) and dynamic exterior parameters (orbit data, attitude data, and sensor alignment). The interior parameters were calibrated using test-field self-calibration with test sites of dense ground control points (GCPs). The exterior parameters were calibrated by adaptive orientation with test sites of worldwide GCPs. These parameters are correlated to the direct geolocation accuracy of the PRISM sensors and are monitored and validated to maintain performance. The performance of the digital surface model (DSM) derived from these geometric model parameters was analyzed. The detailed characteristics of the triangulation results were analyzed by GCPs, and the height accuracy was evaluated based on comparisons with high-accuracy high-resolution reference DSM data sets derived from Lidar and aerial photo matching of various terrain features.

Calibration of PRISM and AVNIR-2 Onboard ALOS “Daichi”

The Advanced Land Observing Satellite [(ALOS); nicknamed ldquoDaichirdquo] was successfully launched on January 24, 2006, and it continues to work very well. This paper describes the calibrations of two optical instruments onboard ALOS, which are the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and Advanced Visible and Near-Infrared Radiometer type 2 (AVNIR-2). PRISM consists of three panchromatic radiometers and is used to derive a digital surface model (DSM) with high spatial resolution, which is an objective of the ALOS mission. AVNIR-2 has four radiometric bands from blue to near infrared, which are used for investigating regional environment issues such as land-use and land-cover classifications, and disaster monitoring. In this paper, we introduce the calibration and validation plan, methodologies, accuracy assessments of the standard products, image quality evaluations for PRISM and AVNIR-2, and their results. Geometric calibration is important in generating a precise DSM by a stereo pair image of PRISM. The relative geometric calibrations of both PRISM and AVNIR-2 are conducted by evaluating accuracies within one scene and evaluating sensor alignments as absolute calibration. For absolute geometric accuracies, we achieved 8.1 m for nadir-looking images and 9.3 m for forward- and backward-looking images of PRISM; we also achieved 114.2 m for AVNIR-2. PRISM is also radiometrically calibrated both relatively and absolutely. PRISM relative radiometric calibration is accomplished by using acquired images over homogeneous targets, such as oceans, deserts, ice, and snow areas, as well as nighttime observation. Simultaneously observed images with calibrated AVNIR-2 are used for absolute radiometric calibration by cross-calibration. The absolute radiometric accuracy of the PRISM nadir-looking radiometer is similar to that of AVNIR-2.

High resolution dsm generation from alos prism - processing status and influence of attitude fluctuation -

Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) carried at Advanced Land Observing Satellite (ALOS) was designed to generate worldwide topographic data in respects of its high resolution and stereoscopic land observation. Following accumulations of the on-orbit data since the launch, the characteristics of its sensor geometry and the capabilities to generate the Digital Surface Model (DSM) have been widely validated in Japan Aerospace Exploration Agency. This paper reports on the DSM processing status, over the four-year period of operations, including a mosaicking process and analysis of error characteristics. We especially focused on an occasional waving noise of the DSM caused by an attitude fluctuation of the satellite. Detailed analysis and correction methods on the waving noise are presented in this paper with inspection of satellite attitude data as well.

High resolution DEM generation from ALOS PRISM data - simulation and evaluation

The Advanced Land Observing Satellite (ALOS) has been developed to contribute to the fields of mapping, precise land coverage observation, disaster monitoring, and resource surveying. The Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM), carried on ALOS satellite is expected to generate worldwide Digital Maps in respects of its high resolution and stereoscopic observation. The development and evaluation of the software for generating Digital Elevation Model (DEM), based on this aim of ALOS operation, is now undertaking for the purpose of equipping the system which producing DEM semi-routinely in the Earth Observation Research and application Center (EORC). In this paper, the softwares outline of functions, the algorithm and the current status of its development and evaluation are described. PRISM consists of three panchromatic radiometers for forward, nadir, and backward views and acquires each image in the same orbit at almost the same time. It enables to generate more precision DEM frequently than usual stereoscopic observations. For this specific stereo image configuration, the triplet images matching algorithm is applied for the DEM generation. To evaluate the algorithm, Three Line Scanner (TLS) data is used as the PRISM simulation data and the Lider DEM is used as the reference data. The absolute accuracy of generated DEM is estimated in this simulation

High resolution DSM generation from ALOS PRISM — Status updates on over three year operations

Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) carried by Advanced Land Observing Satellite (ALOS) was designed to generate worldwide topographic data in respects of its high resolution and stereoscopic observation. Japan Aerospace Exploration Agencys (JAXAs) Earth Observation Research Center (EORC) has widely assessed the on-orbit geometric performance of PRISM sensors since the launch in January 2006. This ongoing activity has generated various geometric performance data over three year on-orbit period of operations. EORC also performed the data analysis of digital surface model (DSM) derived from these geometric performance data. The detailed characteristics of triangulations for PRISM stereo-geometry were evaluated by ground control points (GCPs) and height accuracies of the DSM were also evaluated from the comparison with reference DSM data sets. DSMs are being routinely processed on a scene basis at EORC and mosaicked for global standardized datasets. The preliminary result of the mosaicking process was given with their accuracy analysis.

RPC generations on ALOS PRISM and AVNIR-2

The Rational Polynomial Coefficients (RPC) is being widely used for representing the physical sensor models of satellite optical images. The Remote Sensing Technology Center of Japan (RESTEC) has already released the RPC data sets for Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) and Advanced Visible and Near Infrared Radiometer type 2 (AVNIR-2) onboard Advanced Land Observing Satellite (ALOS) with respect to their physical sensor models calibrated by Japan Aerospace Exploration Agencys (JAXAs) Earth Observation Research Center (EORC). Though the RPC data of PRISM / AVNIR-2 have been widely used in public users since the release, the research on them has not been published. This paper reports on the processing method and accuracy assessment results of the RPC data for PRISM / AVNIR-2. Their adjustment models to ground control points are presented with some experimental results as well as the triangulation accuracies and DSM generations for PRISM.

High resolution DSM generation from ALOS PRISM data - pre-launch simulation and assessment plans

The Advanced Land Observing Satellite (ALOS) has been developed to contribute to the fields of mapping, precise land coverage observation, disaster monitoring, and resource surveying and will be launched in 2005. The Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) carried at ALOS satellite is expected to generate worldwide Digital Maps in respects of its high resolution and stereoscopic observation. The development and evaluation of the software for generating digital surface model (DSM), based on this aim of ALOS operation, is now undertaking for the purpose of equipping the system which producing DSM semi-routinely in the Earth Observation Research and Application Center (EORC). In this paper, the statuses of pre-launch simulations and DSM assessment plans are described. PRISM consists of three panchromatic radiometers for forward, nadir, and backward views and acquires each image in the same orbit at almost the same time. It enables to generate more precision DSM frequently than usual stereoscopic observations. For this specific stereo image configuration, the triplet images matching algorithm is applied for the DSM generation. To evaluate the algorithm, three line scanner (TLS) data is used as the PRISM simulation data. The DSM generation using the JERS-1 OPS stereo images is being performed as the operational simulation. The basic functions of the software such as bundle adjustment, DSM mosaic, mask operation, etc. are evaluated in those simulations. The accuracy assessment of generated DSM is planned to be performed using the LIDAR DSM data, SRTM data, GCP etc.

High resolution DEM generation from ALOS PRISM data -algorithm development and evaluation

The Panchromatic Remote sensing Instrument for Stereo Mapping (PRISM) sensor that will be carried on the Advanced Land Observing Satellite (ALOS) includes creation of digital elevation maps as one of its purposes. PRISM is capable of high spatial resolution and along-track stereoscopic observation. In order to provide software to create a Digital Elevation Model (DEM) semi-routinely at the Earth Observation Research Center (EORC), development of a DEM generation algorithm and software was carried out. The authors considered the basic function of DEM generation software, various processing algorithms for DEM generation were examined, and a trial production and evaluation which used test data was performed This paper reports the resulting processing method, and evaluation of results, of DEM generated from test data consisting of the nadir and forward images from JERS-1/OPS.

Status of “ALOS World 3D (AW3D)” global DSM generation

The Japan Aerospace Exploration Agency is generating the global digital elevation/surface model (DEM/DSM) and ortho-rectified image (ORI) using the archived data of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS, nicknamed “Daichi”), which was operated from 2006 to 2011. The overview and the processing status of the global DSM/ORI dataset generation project called “ALOS World 3D” (AW3D) is introduced in this paper. It is necessary to consider data processing strategies, since the processing capabilities of the level 1 standard product and AW3D products must be developed both hardware and software to achieve the project aims. The processing strategies and an initial validation of generated DSM dataset are described. As an initial validation results, 4.10 m of height accuracy as root mean square error was confirmed. The generation and distribution of a lower resolution AW3D DSM dataset is also introduced.

High resolution DSM generation from ALOS PRISM - Archiving and mosaicking

Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) carried by Advanced Land Observing Satellite (ALOS) was designed to generate worldwide topographic data with its high resolution and stereoscopic observation. According to this aim, we developed the software of generating Digital Surface Model (DSM) data. Following the accumulations of PRISM stereoscopic observation data during over five year operations, the capabilities of the matching-algorithm for stereo images, as well as the characteristics of processed DSMs, were widely validated. This paper reports on the latest validation results, archiving status, and the mosaicking results of the DSM.