fx

FX allows general arithmetic operations to be performed on an arbitrary number of input cubes. It works by loading whatever input files are specified, if any, then applying a user defined equation to those files and then writing the results to an output cube. For instance, if the user wanted to isolate all pixels in a cube that had a DN greater than 100, then an equation like "f1 * (f1 > 100)" could be applied to the cube.

The equation parser is case insensitive and all braces get converted to parenthesis. Whitespace is ignored. Currently, you must explicitly state all multiplication operations (e.g. 5x will not work, but 5*x will). The modulus (%), AND and OR operators are not implemented yet.

The following table shows all currently supported scalars/special tokens.

SCALARS
Scalar	Description	Example
F#	File operator	f3 denotes third file
# or #.# or .#	Any integer or double.	12, 3.14, .007 are all valid.
band	Current band number	f1 * band
line	Current line number	line + f1
sample	Current sample number	sample / line + f1
pi	Pi (3.14159...)	f1 > (e^pi)
e	Euler's number (2.71828...)	f1 == ln(e)

The following table shows all currently supported operators sorted by precedence (0 = highest precedence). All examples are valid equations that assume one or two files (F1, F2) are loaded.

OPERATORS
Precedence	Operator	Description	Example
0	{ [ ( ) ] }	Parenthesis, brackets, or braces	f2*(f1+[30-{line/pi}])
1	--	Negative sign	--f1 + f2
2	>	Greater than	f1 > f2
3	<	Less than	(f1 < f2) / f2
4	<=	Less than or equal	.505 <= f1
5	>=	Greater than or equal	f1 * (f1 >= 101)
6	==	Equal to	f1 == (f2/2)
7	!=	Not equal to	f1 != f2
8	abs	Absolute value	abs(f2 - f1)
9	min	Minimum	f1 + min(f2)
10	max	Maximum	20 * max(f1)
11	sin	Sine	f1 * sin(123/321)
12	cos	Cosine	cos(.02*50)
13	tan	Tangent	tan(f1/f2)
14	csc	Cosecant	12.3 + csc(f1)
15	sec	Secant	sin(pi/60) + (sec(f2))^2
16	cot	Cotangent	line + cot(f1) - 42
17	asin	Arcsine	0.006 ^ asin(f1*5)
18	acos	Arccosine	acos(1/[2*pi])
19	atan	Arctangent	atan(f1/e)
20	atan2	Arctangent2	atan2(--10 5.5)
21	sinh	Hyperbolic sine	55 + sinh(f2)
22	cosh	Hyperbolic cosine	cosh(sample^pi)
23	tanh	Hyperbolic tangent	tanh(f1)
24	log or ln	Natural log	ln(abs(1/[f2-f1]))
25	log10	Log base 10	99 + log10(f1-160)
26	sqrt	Square root	sqrt(abs[1000 - f2])
27	<<	Left shift. Note: pixel shift, not bitwise	f1 << 250
28	>>	Right shift. Note: pixel shift, not bitwise	f2 + (f1 >> 500)
29	^	Exponent	f1 ^ 3
30	*	Multiplication	10 * f1
31	/	Division	f2 / f1
32	+	Addition	123 + 0.004 + f1
33	-	Subtraction	10 - (--f1)

In this example, two images will be added to each other

fx f1=../isisTruth.cub+1 f2=../isisTruth.cub+2 to=../result.cub equation=f1+f2

FX Gui

Example Gui Screenshot of GUI with parameters filled in to perform a calculation on the input image.

Input image	Band 1 Parameter Name: F1 This is an input image for the FX example.
Input image	Band 2 Parameter Name: F2 This is an input image for the FX example.

Output image showing results of the FX application.

Output image Parameter Name: TO This is the 500 by 500 output image of the results.