ABX: Analyze Pixel Statistics in an Image

           
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.