I2SP

Derive spectra from an image


EnvironmentsPYTHON :: EASI :: MODELER
Batch ModeYes
Quick linksDescription :: Parameters :: Parameter descriptions :: Details :: Related

Back to top

Description


I2SP derives an image spectrum from each band vector (that is, for each pixel) within an image region, or a single mean image spectrum from the mean band vector for the region, and outputs the individual image spectra or mean image spectrum to a spectra library file.
Back to top

Parameters


Name Type Length Value range
Target Name String 0 - 1 Default: no target name specified
Mean Spectrum String 0 - 1 YES | NO
Default: YES
Input Window Integer 0 - 4  
InputBitmap: Input bitmap Bitmap port 0 - 1  
Spectral Library Format String 0 - 1 SPCB | XLS | TXT
Default: SPCB
Input image channel: Input raster channel(s) Raster port 0 - 1024  
Wavelength Interval Float 0 - 2  
Valid Bands Only String 0 - 1 YES | NO
Default: NO
Radiometric Transformation Level Integer 0 - 1  
Back to top

Parameter descriptions

Target Name

Specifies the contents of the Target field in the spectrum output.

For example, if this parameter is specified as "limestone", the string "limestone" will be included in the Target field of each output spectrum. The default value is "no target name specified".

Mean Spectrum

Specifies whether or not the mean spectrum for the specified image region is to be derived and output. The default value is "YES".

Input Window

Specifies the rectangular image region (Xoffset, Yoffset, Xsize, Ysize) read from the input channels, from which the individual spectra or a mean spectrum will be derived.

Either an input window (DBIW) or an input bitmap (DBIB) must be specified. If an input bitmap is specified, this parameter is ignored.

Xoffset, Yoffset define the upper-left starting pixel coordinates of the window. Xsize is the number of pixels that define the window width. Ysize is the number of lines that define the window height.

If neither an input window (DBIW) or an input bitmap (DBIB) is specified, the entire image is processed.

InputBitmap: Input bitmap

Specifies the bitmap channel in the input file that indicates the region from which the individual spectra or a mean spectrum will be derived.

Either an input bitmap (DBIB) or an input window (DBIW) must be specified. If an input window is specified, this parameter is ignored.

Spectral Library Format

Specifies the type of the output spectral library file.

Supported file types are:
Note: If the "TXT (text file) type is specified, a file with a ".gav" extension is also generated; this file contains the schema for the file.

Input image channel: Input raster channel(s)

Specifies the input image channel(s) that contain a subset of the input data set bands from which to derive the individual spectra or mean spectrum.

The input file may contain channels that do not store data set bands; the image metadata indicates which channels do. The default is all data set band channels.

Wavelength Interval

Specifies that the selected bands are to be restricted to those whose center wavelength is either inside or outside a closed interval, specified in nanometers. The default is no restriction.

The wavelength interval may be specified as follows:

This parameter has no effect if the input file contains no band center wavelength metadata.

Valid Bands Only

Specifies whether the selected bands are to be restricted to those with "plot" or "bmask" (begin mask) quality values. The default value is NO (no restrictions).

This parameter has no effect if the input file contains no band-validity metadata.

Radiometric Transformation Level

Specifies the radiometric transformations associated with the data set be applied to the stored pixel values before they are used to derive individual spectra or mean spectrum. The default is to apply the full sequence of transformations.

This parameter has no effect if the input file metadata contains no radiometric transformation parameter values.

Back to top

Details

The image metadata from the I2SP input data set must contain a response profile for each band.

Note: If you run I2SP to generate individual spectra (MEANSP = "NO"), keep in mind that the disk space required by the spectra greatly exceeds that required by the same data in image format. I2SP is designed with the assumption that an input window (DBIB) or input bitmap (DBIW) will generally be used to restrict the processing to a small subset of the image.

The output spectra or spectrum can be restricted to those bands whose center wavelength values are either inside or outside a user-specified wavelength interval, are valid (that is, they have "plot" or "bmask" quality values, and are stored in a user-defined set of output channels.

The individual or mean spectra may be generated from image values that are the result of applying all or part of the sequence of radiometric transformations stored in the data set's image metadata.

Band Quality

A band quality value attached to each band allows certain bands to be excluded from plotting (plots of band value versus wavelength) or from processing.

Bands with a quality value of either "plot" or "bmask" are considered to be valid in the sense that their values should not excluded from plotting or processing on the basis of noise content. The user is not prevented, however, from omitting such bands from a user-defined band selection based on wavelength or storage channel.

Bands with a quality value of either "skip" or "mask" are excluded from processing if the VALONLY (Valid Bands Only) parameter is set to YES, specifying that only valid bands are to be processed.

Bands with a "mask" quality value are commonly removed from the data set. A valid band that immediately precedes a mask band has a "bmask" (for "begin mask") quality value. When mask bands are removed, remaining bmask bands indicate where the removal occurred.

Parent topic: I to J
Next topic: IDINT
Related functions
SP2RT

© PCI Geomatics Enterprises, Inc.®, 2024. All rights reserved.