The Planned ISO TC 211 Standard Project on Radiometric Calibration and Validation of Remote Sensing

1
The Planned ISO TC 211 Standard Project on
Radiometric Calibration and Validation of Remote
Sensing Data

• Liping Di
• Laboratory for Advanced Information Technology
  and Standards (LAITS)
• George Mason University
• 9801 Greenbelt Road, Suite 316-317
• Lanham, MD 20706
• lpd_at_rattler.gsfc.nasa.gov

2
Introduction

• Remote sensing is one of the major methods for
  collecting geospatial data.
• Both public and private sectors have been
  involved in the remote sensing activities.
• Remote sensing data have been widely used in all
  aspects of human socio-economic activities,
  ranging from the global change research to
  decision making.
• Those research and applications normally requires
  data collected by multiple sensors and provided
  by different data providers.
• Those data are normally analyzed by users through
  GIS/Image process systems to derive useful
  information.
• Without basic standards for remote sensing data
  and system, it is very difficult to
• integrate data from multiple sources,
• share data among the data providers and users,
• interoperate between data systems.

3
The ISO TC211

• A technical committee of the International
  Organization for Standardization (ISO),
  responsible for setting international standards
  on geographic information.
• Since 1997, ISO TC 211 has been worked on
  developing international standards in the area of
  the imagery and gridded data, which includes
  remote sensing data.
• ISO 19121-Imagery and Grid Data
• ISO 19124-Imagery and gridded data components
• ISO 19129-Imagery, gridded and coverage data
  framework
• ISO 19130-Sensor and data models for imagery and
  gridded data
• ISO 19115.2-Metadata Extensions for imagery and
  gridded data
• ISO 19101.2-Reference Model Imagery
• Planned new TC211 projects on remote sensing
• Radiometric calibration and validation for remote
  sensing data.
• Rules for encoding imagery and gridded data.

4
Categories of remote sensing data

• There are two major types of properties in remote
  sensing data.
• Geometric.
• Contents.
• Based on geometric properties, remote sensing
  data can be classified into two major categories
• Georeferenceable ungeorectified remote sensing
  data such as swath data.
• Georectified (include ortho-rectified).
• Based on their contents, remote sensing data can
  be categorized into
• Images the cell value subject to interpretation
  for its geographic/geophysical meanings.
• Thematic gridded data-geographic meaning
  assigned.
• The ISO 19130 standardizes the geometric aspects
  of georeferenceable remote sensing data.
• Defined sensor models and data model.

5
ISO 19130-Sensor and Data Models for Imagery and
Gridded Data

• It specifies a sensor model describing the
  physical and geometrical properties of each kind
  of photogrammetric, remote sensing and other
  sensors that produces imagery type of data.
• It defines a conceptual data model that
  specifies, for each kind of sensor, the minimum
  content requirement and the relationship among
  the components of the content for the raw data
  that was measured by the sensor and provided in
  an instrument-based coordinate system, to make it
  possible to geolocate and analyze the data.
• The standard defines the ways for providing the
  geolocation information, but not the geolocation
  methods itself.
• Currently experts from eleven countries and five
  international organizations form the project
  team.
• Australia, Canada, France, Germany, Japan,
  Malaysia, Saudi Arabia, South Africa, South
  Korea, Thailand, USA.
• OGC, CEOS, IHO, DGIWG, and ISPRS.
• The FGDC Swath Standard is the basis for the data
  model part of the standard.

6
Data Model for Georefereable Dataset

• ISO 19130 defines a data model for georefereable
  datasets. The top level UML model is shown

7
The needs for the radiometric standard

• Standardizing the description of radiometric
  properties of remote sensing data is very
  important for data utilization and sharing.
• Both in ISO 19115- Geographic metadata and in ISO
  19130 sensor and data models, there is a
  placeholder for radiometric class.
• No further definitions were specified.
• There is no standard in ISO to specify the
  radiometric properties and radiometric
  calibrations of remote sensing data.
• The ISO TC 211 WG 6 realized the importance of
  standardizing the radiometric properties of
  remote sensing data
• It started to discuss the needs for such
  standards in Year 2002.
• WG6 briefed the plan for an ISO standard project
  on radiometric calibration and validation of
  remote sensing data at ISO TC211 Plenary in May
  2003.
• WG6 authorized the ISO 19130 project team to
  start the preparatory work on the subject at the
  same time.

8
The Preparatory Work

• An ISO standard project typically has the
  following stages
• Proposal, Working Draft (WD), Committee Draft
  (CD), Draft International Standard (DIS), Formal
  Draft International Standard (FDIS), and
  International Standard (IS).
• The main tasks for the preparatory work are
• Prepare a new work item proposal (NWIP) for the
  new project.
• Inform the possible stakeholders the planned new
  ISO project.
• Dr. Liping Di of GMU, the chair of ISO 19130,
  took the lead for preparing the new work item
  proposal.
• A draft NWIP has been prepared and was briefed at
  the ISO TC WG6 meeting in Berlin in October 2003.
• It is planned the proposal will be submitted to
  ISO TC 211 by U.S. national body as a U.S.
  Contribution.
• A project team will be formed once the proposal
  is approved by ISO TC 211.
• The project team consists of a project chair, an
  editor, and experts nominated by the members and
  liaison organizations of the TC.
• It is expected the U.S. will submit the proposal
  to ISO TC 211.

9
The Scope

• The tentative title for the new ISO standard
  project is Geographic Information- Radiometric
  calibration and validation of remotely sensed
  data.
• The standard covers two groups of remote sensing
  data
• Radiometrically un-calibrated data (e.g., data
  still in sensor reading as DN)
• Radiometrically calibrated data (e.g., radiance),
  but not the thematic data.
• For the un-calibrated data,
• For each type of remote sensing sensors, the
  standard defines all necessary parameters
  required to quantitatively derive physical values
  from raw sensor measurements and evaluate their
  quality.
• The standard specifies the information that is
  needed to define the response of the system to
  input signals.
• For calibrated data,
• The standard defines the ways for reporting the
  methods for the radiometric calibration/correction
  , the accuracy and precision of the calibration,
  and the methods for determining the accuracy and
  precision.

10
Purpose

• The purpose of this International Standard is to
  define standard content that is necessary for the
  radiometric calibration of sensors measurements
  and the validation of the results.
• An essential aspect of deriving geographical
  information from sensor measurements is the
  conversion of the raw data values into physical
  variables that can be interpreted in the context
  of geographical information. To be able to do so,
  the instrument must be calibrates its
  radiometric properties and its response to input
  signals must be known. This standard will define
  the precise information that must be provided if
  this process is to be carried out for different
  kinds of measuring systems.

11
The Content of the Standard

• The current thoughts on the content of the
  standards envision two parts.
• The first part will define, for each type of
  sensors, the terms and definitions for the
  parameters and their quality measurements
  required for the radiometric correction of raw
  remote sensing data products acquired by the type
  of sensors.
• The second part will define the methodology for
  reporting the radiometric correction and
  validation procedures and the radiometric
  fidelity of radio-metrically corrected remote
  sensing data.

12
Sensor classification

• For the purpose of this standard, remote sensors
  are grouped into two groups
• active sensors
• passive sensors
• Each group of sensors will further classify into
  five types based on the wavelength the sensor
  works
• visible/near infrared (optical), thermal
  infrared, microwave, radio wave, sound wave.
• A remote sensing instrument may have multiple
  bands working on different wavelength, each band
  is considered as a sensor.
• The standard will focus on optical, thermal, and
  microwave, both active and passive.

13
Cooperative development of the standard

• A standard setting process is a
  consensus-building process.
• A successful standard should be developed by as
  many stakeholders as possible.
• Because of the importance of this planned
  standard to the remote sensing, the international
  remote sensing community should participate fully
  in the development of standard.
• The International Society for Photogrammetry and
  Remote Sensing (ISPRS),
• The Committee on Earth Observation Satellites
  (CEOS).
• The IEEE Geoscience and Remote Sensing Society
  (IGARSS)
• The International workshop on Radiometric and
  Geometric Calibration organized by the ISPRS/CEOS
  joint task force is the important venue for
  reporting the best international practices on
  radiometric and geometric calibration.
• ISOTC 211 expects that results of this workshop
  will serve as one of the information sources for
  drafting the international standards. It also
  expect the above mentioned international
  organizations will be the major force for
  setting the standard.