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  >  Docs Center  >  ENVI API  >  Processing  >  ENVICalculateQUACGainOffsetTask

ENVICalculateQUACGainOffsetTask

ENVICalculateQUACGainOffsetTask

This task calculates the gain and offset for QUick Atmospheric Correction (QUAC)® on multispectral or hyperspectral imagery.

Note: This function requires a separate license for the ENVI Atmospheric Correction Module; contact your sales representative for more information.

Example


; Start the application
e = ENVI()
 
; Open an input file
File = Filepath('qb_boulder_msi', Subdir=['data'], $
  Root_Dir=e.Root_Dir)
Raster = e.OpenRaster(File)
 
; Get the task from the catalog of ENVITasks
Task = ENVITask('CalculateQUACGainOffset')
 
; Define inputs
Task.INPUT_RASTER = Raster
 
; Run the task
Task.Execute
 
; Print the bad bands list, gains, and offsets
Print, 'Bad bands: ',Task.BBL
Print, 'Gains: ',Task.GAIN
Print, 'Offsets: ',Task.OFFSET

Result:

Bad bands: 1 1 1 1
Gains: 0.0012088706   0.00075686112   0.00098287757   0.00099052524
Offsets: -0.18737493     -0.13812715    -0.093373366    -0.053983625

Syntax


Result = ENVITask('CalculateQUACGainOffset')

Input properties (Set, Get): INPUT_RASTER, SENSOR

Output properties (Get only): BBL, GAIN, OFFSET

Properties marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Properties marked as "Get" are those whose values you can retrieve but not set.

Methods


This task inherits the following methods from ENVITask:

AddParameter

Execute

Parameter

ParameterNames

RemoveParameter

Properties


This task inherits the following properties from ENVITask:

COMMUTE_ON_DOWNSAMPLE

COMMUTE_ON_SUBSET

DESCRIPTION

DISPLAY_NAME

NAME

REVISION

TAGS

This task also contains the following properties:

BBL

This is the bad band list, returned as a byte array in the form of [number of bands]. A value of 1 indicates a good band, and 0 indicates a bad band.

GAIN

This parameter contains the data gain values that can be applied to the raster, returned as a double-precision array in the form of [number of bands].

INPUT_RASTER (required)

Specify a raster to calculate the gain and offset for QUick Atmospheric Correction (QUAC).

OFFSET

This parameter contains the data offset values that can be applied to the raster, returned as a double-precision array in the form of [number of bands].

SENSOR (optional)

Specify one of the following strings, indicating the sensor type of the input raster:

Generic / Unknown Sensor
Highly Vegetated Scenes
AISA-ES
ALI
ASAS
AVIRIS
CAP ARCHER
CASI
COMPASS
HYCAS
HYDICE
HyMap
Hyperion
Landsat TM/ETM/OLI
LASH
MARS
MODIS
QuickBird
RGB
WorldView-2
Near Infrared (NIR)
Near-Shortwave Infrared (NIR-SWIR)
  • If SENSOR is not set, then the task uses the Generic/Unknown Sensor option to guess the best sensor type, based on the number of input bands and their wavelengths.
  • Select the Highly Vegetated Scenes option if the image is highly vegetated.
  • Select the Near Infrared (NIR) option if the input raster has more than 70 bands and the wavelengths span the near-infrared region.
  • Select the Near-Shortwave Infrared (NIR-SWIR) option if the input raster has more than five bands and the wavelengths span the near-shortwave infrared region.

Version History


ENVI 5.3

Introduced

API Version


3.2

See Also


ENVITask, ENVITask::Parameter, ENVIGainOffsetWithThresholdRaster, ENVIQUACRaster, ENVIQUACTask



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