- Form:ABX source [boxes] [ALL] [W=w1,w2] [SILENT]
[MASK]
-
- [TOTAL=var] [MEAN=var] [HIGH=var]
- [LOW=var] [HIGH_ROW=var] [HIGH_COL=var]
- [LOW_ROW=var] [LOW_COL=var] [SIGMA=var] (redirection)
- [AREA=farea] [P=var]
- source
- specifies the object.
- boxes or BOX=b1,b2...
- list boxes to be used in the analysis.
- ALL
- tells the program to analyze the entire image or spectrum.
- W=w1,w2
- limits the analysis to the wavelength interval w1 to w2 for
wavelength-calibrated spectra.
- SILENT
- do not print output.
- MASK
- ignore masked pixels.
- AREA=farea
- Determine the pixel position where the total reaches
the value farea.
- var
- the name of a variable.
ABX analyzes the statistics of an image or spectrum. It computes the total,
mean, and standard deviation about the mean. It also finds the locations
and values of the highest and lowest pixels. The output of this program
can be redirected.
To analyze the object in regions defined by boxes, give the NUMBERS of the
boxes on the command line. If you give no numbers, the entire image will
be analyzed. Alternatively, specify any number of boxes using the
BOX=b1,b2,... keyword. Examples:
- ABX 3
- Finds the properties of object 3 in the entire image
- ABX 3 1
- Finds the properties of object 3 in box 1
- ABX 2 3 4 5 6
- Analyzes object 2 in boxes 3, 4, 5, and 6
- ABX 2 BOX=3,4,5,6
- Analyzes object 2 in boxes 3, 4, 5, and 6
Note that in ABX, boxes are specified by integers, and not by BOX= keyword,
as is usual in other commands. See BOX to see how to define boxes.
To analyze the entire image or spectrum, use the keyword ALL or simply do
not specify a box number. Any box specifiers on the command line are
ignored. To analyze part of a wavelength-calibrated spectrum, use W= to
specify the part in Angstroms.
ABX finds the image mean, total count over all pixels, values of the
highest and lowest pixels, location of the highest and lowest pixels, and
the standard deviation of the counts in the pixels about the mean. A table
of the results is printed on the output device.
ABX will store the values for the various properties of the image in
variables if certain keywords are included on the command line:
- TOTAL=var
- Stores the total count of all the pixels in 'var'
- MEAN=var
- Stores the average of the image
- HIGH=var
- Stores the VALUE of the pixel with the highest count
- LOW=var
- Stores the VALUE of the pixel with the lowest count
- HIGH_ROW=var
- Stores the row number in which the highest-valued
pixel is located
- HIGH_COL=var
- Stores the column number in which the
highest-valued pixel is located
- LOW_ROW=var
- Stores the row number in which the lowest-valued
pixel is located.
- LOW_COL=var
- Stores the column number in which the lowest-valued
pixel is located.
- SIGMA=var
- Stores the standard deviation of the pixel values
about the mean.
- P=var
- Stores the pixel where the total reaches farea
(using AREA=farea) keyword.
Examples of storing information in variables are:
- ABX 1 3 MEAN=M3 SIGMA=SIG3
- Analyzes image 1 in box 3, storing
the mean in variable M3 and the standard deviation in SIG3.
- ABX 2 7 HIGH_ROW=HR HIGH_COL=HC
- Analyzes image 2 in box 7,
storing the location of the highest-valued pixel in HR and HC
The use of the variable-setting keywords should be used only when you
analyze an image one box at a time, as the values will be loaded into the
variables only for the last box analyzed.
SILENT is used to prevent printing of the output. This is helpful in
procedures when variables are set.