TYPE: COP
TITLE: Gradient COP

This operation does a variety of gradient related effects.

Right click on the dialog '?' help for more help on VEX operations. 

Examples:
    UV Gradient - Computes the UV gradient of the image, which is a 2D vector
		  which points in the direction of greatest luminance increase.
		  The magnitude of the vector is the increase amount. Similar to
		  the results produced by the Bump COP.
    Normal Map  - Computes a normal map from the gradient. The normal and the
		  gradient are similar: the normal is a normalized 3D vector 
		  with the Z component set to 1 and  X & Y set to the U & V 
		  values of the gradient.
    Gradient Magnitude    - Computes the gradient magnitude, which appears as a 
			    luminance edge-detected image.
    Thresholded Magnitude - Computes the gradient magnitude and only accepts
                            values between the low and high threshold values.
			    If normalize is on, the values are mapped from low
			    to high to 0 to 1.

Parameters
    Gradient Type      - The channel used to compute the gradient.
    Output             - The type of output produce (see above). 
    Low/High Threshold - The low and high thresholds for thresholded magnitude
                         output.
    Normalize          - If UV Gradient output is used, this normalizes the 
                         gradient's magnitudes to 1.
                         If Thresholded Magnitude is used, this maps the
                         low to high range to 0 - 1.

Mask & Plane Scope, Frame Scope
    Overview - See extra help (Middle click on the dialog '?' help).

Local Variables:
    L   - Sequence length
    S   - Start of sequence
    E   - End of sequence
    IL  - Input sequence length
    SR  - Sequence frame rate
    NP  - Number of planes in sequence
    W,H - Width and height of image
    I   - Image index (0 at start frame)
    IT  - Image time (0 at start frame)
    AI  - Current plane array index
    PI  - Current plane index
    PC  - Num of channels in current plane
