Use this procedure to generate test images.

Syntax

ENVI_DOIT, 'GEN_IMAGE_DOIT', DATA_TYPE=value, /IN_MEMORY, MAX_VAL=value, MEAN=value, METHOD={0 | 1 | 2 | 3 | 4 | 5}, MIN_VAL=value, NB=integer, NL=integer, NS=integer, OUT_NAME=string, R_FID=variable [, SEED=value], SIGMA=value, VAL=value

Keywords

DATA_TYPE

Use this keyword to specify the IDL data type of the file, using the following IDL convention.

  • 1: Byte (8 bits)
  • 2: Integer (16 bits)
  • 3: Long integer (32 bits)
  • 4: Floating-point (32 bits)
  • 5: Double-precision floating-point (64 bits)
  • 6: Complex (2x32 bits)
  • 9: Double-precision complex (2x64 bits)
  • 12: Unsigned integer (16 bits)
  • 13: Unsigned long integer (32 bits)
  • 14: Long 64-bit integer
  • 15: Unsigned long 64-bit integer

IN_MEMORY

Set this keyword to specify that output should be stored in memory. If you do not set IN_MEMORY, output will be stored on disk and you must specify OUT_NAME (see below).

MAX_VAL

Use this keyword to specify the maximum value when METHOD=1, 2, 3 or 5.

MEAN

Use this keyword to specify the mean value when METHOD=4.

METHOD

Set this keyword to one of the following values to specify which type of test image to generate.

  • 0: Constant
  • 1: Horizontal ramp
  • 2: Vertical ramp
  • 3: Random noise (uniform)
  • 4: Random noise (normal)
  • 5: Gaussian point spread function

MIN_VAL

Use this keyword to specify the minimum value when METHOD=1, 2, 3 or 5.

NB

Use this keyword to specify the number of bands in the output image.

NL

Use this keyword to specify the number of lines in the output image.

NS

Use this keyword to specify the number of samples in the output image.

OUT_NAME

Use this keyword to specify a string with the output filename for the resulting data. If you set the keyword IN_MEMORY, you do not need to specify OUT_NAME.

R_FID

ENVI Classic library routines that result in new images also have an R_FID, or “returned FID.” This is simply a named variable containing the file ID to access the processed data. Specifying this keyword saves you the step of opening the new file from disk.

SEED (optional)

Use this keyword to specify a random number seed when METHOD=3 or 4.

SIGMA

Use this keyword to specify the Gaussian sigma value when METHOD=4 or 5. For METHOD=5, +/- one sigma is equal to the number of samples.

VAL

Use this keyword to specify the constant value for constant images.

API Version

4.2