Channel-to-Wavelength Matching
Channel-to-Wavelength Matching assigns physical wavelength values to image channels when the current hyperspectral cube contains channels or band indices that do not yet have a reliable wavelength axis.
Overview
Channel-to-Wavelength Matching assigns physical wavelength values to image channels when the current hyperspectral cube contains channels or band indices that do not yet have a reliable wavelength axis.
IDCubePro provides two matching workflows: Fast Matching and Accurate Matching.
- A dataset contains spectral channels but the wavelength vector is missing, incomplete, or unreliable.
- A reduced or compressed spectral dataset needs to be mapped back to physical wavelength values.
- A wavelength-calibration workflow is required after channel reduction or resampling.
Do not use this tool when the current dataset already contains a correct physical wavelength vector.
Fast Matching uses the standard ChannelToWavelength workflow.
- A routine or approximate channel-to-wavelength assignment is sufficient.
- You want a quicker calibration workflow.
- The wavelength relationship is expected to be relatively straightforward.
Fast Matching is generally the preferred first choice when speed is more important than maximum alignment precision.
Accurate Matching uses the ChannelToWavelengthCropping workflow.
Choose Accurate Matching when:
- Wavelength alignment accuracy is more important than speed.
- A more detailed cropping-based matching workflow is appropriate.
- The spectral/channel correspondence requires closer manual or spatial refinement.
Accurate Matching may require more user interaction than Fast Matching.
1. Open Match Channels to Wavelengths from the Preprocessing Center.
2. Choose Fast Matching or Accurate Matching.
3. Follow the matching workflow that opens.
4. Review the resulting wavelength assignment.
5. Continue analysis only after confirming that the wavelength axis is reasonable for the dataset.
When matching completes successfully, the current working dataset should contain an updated wavelength vector associated with its spectral channels.
The spectral axis can then be displayed and interpreted in physical wavelength units instead of channel or band indices, provided the selected matching workflow successfully establishes a physical wavelength mapping.
IDCubePro remains Ready while you are choosing a matching method.
When a matching workflow is launched, the main application status changes to Processing and returns to Ready after the matching function finishes.
If matching fails, IDCubePro reports an error and then returns to Ready.
Wavelet / Reduced-spectrum Workflows
Channel matching can also be used after spectral reduction workflows when the output channels no longer correspond directly to the original physical wavelength grid.
For example, the Wavelet Reduced Spectrum workflow can optionally call Fast Matching or Accurate Matching after the reduced cube has been created.
Band Index Vs Physical Wavelength
A band index such as 1, 2, 3, ... identifies channel position only.
A physical wavelength axis contains calibrated wavelength values such as 450 nm, 550 nm, or 700 nm.
Do not interpret band indices as physical wavelengths unless a calibration or matching step has established that relationship.
After wavelength matching, verify that:
- Wavelength values are finite.
- The number of wavelength values matches the number of spectral channels.
- The wavelength ordering is physically reasonable.
- The wavelength range is consistent with the instrument or source data.
- Known spectral features occur at approximately expected wavelengths when such references are available.
Channel-to-wavelength matching cannot recover wavelength information that is fundamentally absent from the source data without an appropriate reference, calibration, or matching basis.
The quality of the final wavelength axis depends on the information available to the selected matching workflow.
Channel matching operates on the current working dataset. It does not automatically overwrite the original source file on disk.
Use the normal IDCubePro Save / Export workflow if you want to save the matched dataset.
Choosing Between The Two Methods
Use Fast Matching first for routine work.
Use Accurate Matching when the Fast result is insufficient or when higher alignment precision is required.
Channel-to-Wavelength Matching Close Channel-to-Wavelength Matching help.