Brightness Node

The Brightness node enables you to vary the brightness of an image by assigning a value to the Brightness parameter.

The Brightness node allows you to specify an offset for the brightness value. The following illustration shows the change to the color range when the Brightness parameter is changed from 1.0 to 2.0 and the Offset parameter is changed from 0 (the default) to 0.2.

The Brightness node performs the following computation:

V = ((V - Offset) * Brightness) + Offset

For Brightness settings greater than 1, the Brightness node boosts values above the offset and attenuates values below it. For Brightness settings less than 1, the Brightness node attenuates values above the offset and boosts values below it.

For integer data, the Brightness node clamps values at the maximum for the colorspace (255 or 65535). Float values are not clamped.

Brightness Parameter Tab

Brightness

You set the Brightness parameter by keying in a numerical value between 0 and 10.0 (inclusive) or by using the mouse to set the tuner to the desired value. The default value is 1.0, indicating no change to the image.

Offset

You set the Offset parameter by keying in a numerical value between -1.0 and 1.0 (inclusive) or by using the mouse to set the tuner to the desired value. This value determines the offset point for the brightness adjustment. (See the illustration at the top of this node description).

Channel Mask

The Channel Mask parameter enables you to inhibit the modification of any channel by deselecting the Red, Green, Blue, Alpha, or Other channel icons.

Control Image Parameters

The Control Action and Control Channel menus enable you to specify how an optional control image input will govern the node operation, as explained in "Using Control Images with Filter Nodes ."




Table of Contents | Index



Copyright 1996-1999 by Silicon Grail Corporation