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The MATHS sub-menu contains commands which allow mathematical
operations to be applied to the pixels of the current region of interest.
The MATHS sub-menu is shown in Figure 27.
Figure 27:
The MATHS Sub-Menu Commands
![\begin{figure}
\begin{center}
\includegraphics [width=17cm]{fit2d_mathsmenu.ps}
\end{center}\end{figure}](img30.gif) |
The available commands and their functions are:
- EXIT: Leave MATHS sub-menu, and return to
IMAGE PROCESSING (GENERAL) main menu.
- SCALAR /:
Pixel by pixel division of the current region of
interest by an input scalar value. The user is prompted DIVISION
CONSTANT for the scalar which will be used for division.
- HELP: Detailed help text on the interface and the
available commands. The operation is performed in-place.
- LOG(10): Take the logarithm (base-10) of all the pixel values
in the current region of interest. If zero or negative values are
encountered the user is prompted LOWER THRESHOLD, and the value
entered will be used as the lowest value in the output. The operation is
performed in-place. (Note: This changes the data values, unlike the log
scaling option in the Z-SCALING menu, which only affects the
display.)
- SUBTRACT:
Subtracts pixel by pixel, the image in the ``memory'' from the image in
the current data array, within the current region of interest. The
``memory'' data must be defined throughout the current region of
interest or a warning message will be produced. The operation is in-place.
- ?: Help text with short explanation of commands.
- SCALAR *:
Pixel by pixel multiplication of the current region of
interest by an input scalar value. The user is prompted MULTIPLICATION
CONSTANT for the scalar which will be used for the multiplication.
- MULTIPLY:
Multiples pixel by pixel, the image in the ``memory'' and the image in
the current data array, within the current region of interest. The
``memory'' data must be defined throughout the current region of
interest or a warning message will be produced. The operation is in-place.
The original data is replaced by the result of the multiplication.
- THRESHOLD:
Allows minimum and maximum thresholding values to be set for the current
region of interest. The user is prompted MINIMUM THRESHOLD VALUE
and MAXIMUM THRESHOLD VALUE. Values outside of the set range are
replaced will the minimum or the maximum value. The original data is
replaced. Note: This operation is in general non-reversible.
- HELP: Detailed help text on the interface and the
available commands. The operation is performed in-place.
- ADD:
Add pixel by pixel, the image in the ``memory'' and the image in
the current data array, within the current region of interest. The
``memory'' data must be defined throughout the current region of
interest or a warning message will be produced. The operation is in-place.
The original data is replaced by the result of the addition.
- NORMALISE: Divide pixel by pixel by the largest value,
throughout the current region of interest. The original data is replaced
by the result of the division.
- X(n):
Calculate pixel by pixel xn where x is a user
specified constant, and n is the value of each input pixel. The user
is prompted ENTER POWER for the value of x. If x is 10.0 this
operation is the partial inverse of the LOG(10) operation. It is
only a partial inverse in the case that values have been thresholded
in the LOG(10) operation.
- SCALAR +:
Pixel by pixel addition of the current region of
interest with an input scalar value. The user is prompted ADDITION
CONSTANT for the scalar which will be used for the addition.
- DIVIDE:
Divides pixel by pixel, the image in the current data array by the image in
the ``memory'', within the current region of interest. The
``memory'' data must be defined throughout the current region of
interest or a warning message will be produced. The operation is in-place.
- STATISTICS:
Allows the user to define an arbitrary polygon region with graphical
coordinate input, and calculates a number of statistics in the region.
If only two coordinates are input, they define opposite corners of a
rectangular region for the calculation. The result is displayed in a
text window, and can be saved to an output file.
A typical result of the STATISTICS operation is shown below.
Extremes of polygon (X/Y min, X/Y max) =
704.85 993.16 761.94 1136.49
Number of pixels inside polygon = 3237
Smallest value = 1.0841 Largest value = 1.4180
Total intensity = 3688.0 (square root = 60.729 )
Average intensity = 1.1393
Root Mean Square (RMS) value = 1.1416
Standard Deviation = 7.15076E-02 Gain (?) = 4.48806E-03
Integrated intensity minus previous average = 61.607
Square root of above = 7.8490
The Integrated intensity minus previous average contains the
integrated sum of pixel values minus the previous average value. Thus,
if first a background region is defined, and then a peak is defined
a simple form of peak integration
is performed.
Next: Example of Dividing One Image
Up: The IMAGE PROCESSING (GENERAL) Interface
Previous: The GEOMETRIC Sub-Menu
Andy Hammersley
8/26/1998