In defining standard image geometry models and submodels, the OGC probably should cooperate with the International Society of Photogrammetry and Remote Sensing ISPRS. Several ISPRS
commissions are doing related work, including: Commission I: Sensors, Platforms and Imagery; Chair: G. Joseph India
Commission II: Systems for Data Processing, Analysis Presentation; Chair: I. Dowman Commission III: Theory and Algorithms; Chair: T. Schenk USA
Author’s Note: The following text discusses several important questions about how the OGC should proceed toward standardizing image geometry models and geometry model data formats.
For each of several needed technical decisions, the OGC TC might make the decision, before issuing the relevant RFP. Alternately, the OGC TC might ask teams responding to the relevant RFP
to recommend each decision. Similarly, the OGC TC might let teams submitting RFCs recommend each decision. The OGC TC would then accept the recommended decision when it approves an
Implementation Specification using that decision. This Section implies Arliss Whiteside’s opinion on many of these needed decisions.
The set of image geometry models or model types to be standardized by the OGC might be completely selected by the OGC Technical Committee TC. Probably better, specific image
geometry models to be standardized might be proposed by vendors, and adopted by the OGC. The types of image geometry submodels to be standardized by the OGC might be more completely
selected by the OGC TC. These submodels might be organized into categories, such as geometric model e.g. earth curvature, lens distortion, principal point of autocollimation and physical model
e.g. atmospheric refraction, radar or laser properties.
The specific image geometry models and submodels standardized might be largely specified by the OGC TC with the ISPRS, perhaps in the form of model equations. Probably better, specific
image geometry models might be specified by vendors in response to RFPs or in RFCs. Similarly, the forms used to transfer image geometry model data might be specified by the OGC TC or
proposed by vendors. The complete format details for transferring data for each image geometry model should be specified by vendors, in response to a RFP or in a RFC.
2.10.5. Proprietary Image Geometry Models
Although multiple image geometry models should be standardized by the OGC, there will probably also be proprietary image geometry models that are not standardized. These proprietary image
geometry models will be used only when the geometry model implementation software need not be interoperable. Although complete image geometry models may be proprietary, submodels are more
likely to be proprietary. For example, camera internal geometry models are more likely to be proprietary.
These proprietary image geometry models andor submodels are likely to be used by vendors who want to protect the nature of their image geometry andor image geometry model. For these
proprietary models, encryption of the model geometry data andor the implementation software might be used to further conceal the details of the image geometry model.
In order to be useful and used, software implementing the needed image coordinate transformation capabilities using a proprietary image geometry model or submodel probably must:
1. Be provided at no extra cost by the supplier of the images using the model, or by the supplier
of geometry model parameter data for specific images, so there is no need for competition between suppliers
2. Be available for all important computing platforms such as Windows and UNIX
3. Include capabilities and interfaces for all types of geometry model adjustment needed for
image registration, if any such adjustment is needed. These capabilities and interfaces for model adjustment could be designed to hide the specific nature of the model parameters being
adjusted.
4. Support standard interfaces for access to all provided image coordinate transformation
functions, so this software can be easily used with other geometry models and software To help ensure item 4 above, the OGC probably should work with prospective vendors of
proprietary models in the development of standard image geometry model APIs. The OGC should work to ensure that OGC standardized APIs can be used with all anticipated proprietary image
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geometry models. For example, the standardized APIs should allow vendors to tailor the accuracy, computation speed, and other properties of their proprietary model implementations.
To simplify use and implementation, such proprietary image coordinate transformation software might also be:
1. Coded in a programming language that can be executed in many computing environments
such as JAVA 2.
Available for automatic download when needed, over the Internet or other network like JAVA Applets
3. Available on a publicly accessible server for remote execution, over the Internet or other
network. A charge could be levied for such execution.
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3. Essential Model for Image Coordinate Transformation Services
