CREFRAME - Generates a test two-dimensional NDF with a selection of several forms

Description:

This application creates a two-dimensional output NDF  containing artificial data of various forms (see Parameter MODE). The output NDF can, optionally, have a VARIANCE component describing the noise in the data array (see Parameter VARIANCE), and additionally a randomly generated pattern of bad pixels (see Parameter BADPIX). Bad columns or rows of pixels can also be generated.

Usage:

creframe out mode [lbound] [ubound]
$\left\{ {\begin{tabular}{l} mean=? \\ background=? distrib=? max=? min=? ngauss=? seeing=? \\ mean=? sigma=? \\ high=? low=? \end{tabular} } \right.$
mode

Parameters:

BACKGROUND = _REAL (Read)

Background intensity to be used in the generated data array. Must not be negative. (GS mode).

BADCOL = _INTEGER (Read)

The number of bad columns to include. Only accessed if Parameter BADPIX is TRUE. The bad columns are distributed at random using a uniform distribution. [0]

BADPIX = _LOGICAL (Read)

Whether or not bad pixels are to be included. See also Parameters FRACTION, BADCOL and BADROW. [FALSE]

BADROW = _INTEGER (Read)

The number of bad rows to include. Only accessed if Parameter BADPIX is TRUE. The bad rows are distributed at random using a uniform distribution. [0]

DIRN = _INTEGER (Read)

Direction of the ramp. 1 means left to right, 2 is right to left, 3 is bottom to top, and 4 is top to bottom. (RA mode)

DISTRIB = LITERAL (Read)

Radial distribution of the Gaussians to be used (GS mode). Alternatives weightings are:

• "FIX" -- fixed distance, and

• "RSQ" -- one over radius squared.

["FIX"]

FRACTION = _REAL (Read)

Fraction of bad pixels to be included. Only accessed if BADPIX is TRUE. [0.01]

HIGH = _REAL (Read)

High value used in the generated data array (RA and RL modes).

LBOUND( 2 ) = _INTEGER (Read)

Lower pixel bounds of the output NDF. Only accessed if Parameter LIKE is set to null (!).

LIKE = NDF (Read)

An optional template NDF which, if specified, will be used to define the bounds for the output NDF. If a null value (!) is given the bounds are obtained via Parameters LBOUND and UBOUND. [!]

LOGFILE = LITERAL (Read)

Name of a log file in which to store details of the Gaussians added to the output NDF (GS mode). If a null value is supplied no log file is created. [!]

LOW = _REAL (Read)

Low value used in the generated data array (RA and RL modes).

MAX = _REAL (Read)

Peak Gaussian intensity to be used in the generated data array (GS mode).

MEAN = _REAL (Read)

Mean value used in the generated data array (FL, RP and GN modes).

MIN = _REAL (Read)

Lowest Gaussian intensity to be used in the generated data array (GS mode).

MODE = LITERAL (Read)

The form of the data to be generated. The options are as follows.

• "RR" -- Uniform noise between 0 and 1.

• "RL" -- Uniform noise between specified limits.

• "BL" -- A constant value of zero.

• "FL" -- A specified constant value.

• "RP" -- Poisson noise about a specified mean.

• "GN" -- Gaussian noise about a specified mean.

• "RA" -- Ramped between specified minimum and maximum values and a choice of four directions.

• "GS" -- A random distribution of two-dimensional Gaussians of defined FWHM and range of maximum peak values on a specified background, with Poissonian noise. There is a choice of spatial distributions for the Gaussians: fixed, or inverse square radially from the array centre. (In essence it is equivalent to a simulated star field.) The x-y position and peak value of each Gaussian may be stored in a log file, a positions list catalogue, or reported on the screen. Bad pixels may be included randomly, and/or in a column or line of the array.

NGAUSS = _INTEGER (Read)

Number of Gaussian star-like images to be generated (GS mode).

OUT = NDF (Write)

The output NDF.

OUTCAT = FILENAME (Write)

An output catalogue in which to store the pixel co-ordinates of the Gausians in the output NDF (GS mode). If a null value is supplied, no output positions list is produced. [!]

SEEING = _REAL (Read)

Seeing (FWHM) in pixels (not the same as the standard deviation) (GS mode).

SIGMA = _REAL (Read)

Standard deviation of noise to be used in the generated data array (GN mode).

TITLE = LITERAL (Read)

Title for the output NDF. ["KAPPA - Creframe"]

UBOUND( 2 ) = _INTEGER (Read)

Upper pixel bounds of the output NDF. Only accessed if Parameter LIKE is set to null (!).

VARIANCE = _LOGICAL (Read)

If TRUE, a VARIANCE component is added to the output NDF representing the noise added to the field. If a null (!) value is supplied, a default is used which is TRUE for modes which include noise, and FALSE for modes which do not include any noise. [!]

Examples:

creframe out=file ubound=[128,128] mode=gs ngauss=5 badpix badcol=2 max=200 min=20 background=20 seeing=1.5

Produces a 128$\times$ 128 pixel data array with 5 gaussians with peak values of 200 counts and a background of 20 counts. There will be two bad columns added to the resulting data.

Notes:

• The Gaussian parameters (GS mode) are not displayed when the message filter environment variable MSG_FILTER is set to QUIET.

Implementation Status:

• The DATA and VARIANCE components of the output NDF have a numerical type of "_REAL" (single-precision floating point).

• This routine does not assign values to any of the following components in the output NDF: LABEL, UNITS, QUALITY, AXIS, WCS.