integrate3d VEX function

This function will “integrate” the 3d image along the line specified by p0 and p1.

1. float integrate3d(string filename, string channel, vector p0, vector p1)

2. vector integrate3d(string filename, string channel, vector p0, vector p1)

3. vector4 integrate3d(string filename, string channel, vector p0, vector p1)

This function will “integrate” the 3d image along the line specified by p0 and p1.

You can specify additional keyword,value argument pairs to set options for the integration. These arguments must be defined at load time (literals or parameters).

To specify one of the additional arguments, pass the keyword as a string, with the next argument being the value for the keyword. For example ..., "wrap", "clamp", "border", {.1,1,1}).

value specified. This option should not be used if the 3d image contains both positive and negative values as the integration my terminate prematurely. Caveat: The vector forms of this function don’t deal with termination as precisely as the scalar form.

less than 1, limited filtering is done. If the accuracy is greater than 1 higher quality sampling is performed. The default value is 0. Please be cautioned that accurate filtering can be 10 times as expensive for even simple data sets.

the integration

Keyword	Value
maxlimit	Terminate the integration if the computed sum exceeds the
accuracy	Determine the accuracy of integration. If the accuracy is
iscale	Scale the value of the image by the value specified during
filter	Specifies the filter for evaluation (see colormap).
width	Specifies the filter width for accurate integration.

For example:

shadow_amount = integrate3d(file, "density", P, L, "maxlimit", 1, "iscale", shadow_density);