This task performs a difference analysis on a specific band in two images.
Example
This example performs a difference analysis between two images from different dates. The images represent NCEP-Reanalysis 2 air temperatures (K) at the 1000-isobar level, at 0600 hours Zulu time. The first image is from 29 December 2012, and the second is from 31 December 2012. Each image has one band. This example uses sample data from the ENVI installation path.
e = ENVI()
TimeSeriesDir = Filepath('', Subdir=['data','time_series'], $
Root_Dir = e.Root_Dir)
files = File_Search(TimeSeriesDir, 'AirTemp*.dat')
numRasters = N_Elements(files)
rasters = ObjArr(numRasters)
FOR i=0, (numRasters-1) DO $
rasters[i] = e.OpenRaster(files[i])
Task = ENVITask('BuildTimeSeries')
Task.INPUT_RASTERS = rasters
Task.Execute
SeriesFile = Task.OUTPUT_RASTERSERIES
SeriesFile.Set, 0
Image1 = SeriesFile.Raster
SeriesFile.Set, 8
Image2 = SeriesFile.Raster
Task = ENVITask('ImageBandDifference')
Task.INPUT_RASTER1 = Image1
Task.INPUT_RASTER2 = Image2
Task.Execute
DataColl = e.Data
DataColl.Add, Task.OUTPUT_RASTER
View = e.GetView()
Layer = View.CreateLayer(Task.OUTPUT_RASTER)
Syntax
Result = ENVITask('ImageBandDifference')
Input parameters (Set, Get): INPUT_RASTER1, INPUT_RASTER2, OUTPUT_RASTER_URI
Output parameters (Get only): OUTPUT_RASTER
Parameters marked as "Set" are those that you can set to specific values. You can also retrieve their current values any time. Parameters marked as "Get" are those whose values you can retrieve but not set.
Input Parameters
INPUT_RASTER1 (required)
Specify the first raster on which to perform the image band difference.
INPUT_RASTER2 (required)
Specify the second raster on which to perform the image band difference. It must have the same number of columns, rows, and bands as INPUT_RASTER1.
OUTPUT_RASTER_URI (optional)
Specify a string with the fully qualified filename and path of the associated OUTPUT_RASTER.
- If you do not specify this parameter, or set it to an exclamation symbol (!), ENVI creates a temporary file.
- If you set it to the hash symbol (#), ENVI creates a file in the temporary directory, but this file will not be deleted when ENVI closes.
Output Parameters
OUTPUT_RASTER
This is a reference to the output raster of filetype ENVI. It inherits the same map information (projection, datum, pixel size, image rotation) and wavelengths as INPUT_RASTER1.
Methods
Execute
Parameter
ParameterNames
Properties
DESCRIPTION
DISPLAY_NAME
NAME
REVISION
TAGS
Version History
See Also
ENVITask, SAMImageDifference Task, Masking Support in ENVITasks