White Shading

Supported by ...

COLOR cameras only.  

Description

The White Shading feature provides control over the individual red, green and blue channel gains so that non-standard color balance can be achieved.  One-push Auto will attempt to white balance the gains (match the histogram peaks of the brightest area in each color channel) based on the image data in the current ROI.

Note: The auto white shading algorithm is based on a brightfield microscopy where the background is bright and white.  The algorithm balances the brightest areas of the image to white. When used in reflected light microscopy or in colored environments, the brightest areas in the image must be neutral in color.  If not, it is best to perform the auto white shading using a grey card.

Note: White Shading is sometimes referred to as White Balance. In Pixelink Capture for instance, the controls for this feature can be found under White Balance Settings.

White shading is performed prior to other image processing steps and is independent of the white balance (color correction) settings.

Setting a gain parameter to zero will effectively turn off that color channel – it will output a zero value.

Note: Setting a color channel gain to zero and also setting the saturation feature to zero will still result in values on that color channel. This is due to the fact that grey tones (from zero saturation) require equal output from all 3 color channels. The color channel gains affect the raw sensor data and any image processing performed on-board the camera, like the saturation adjustment, may modify the values on the color channels.

Note: If the FEAURE_AUTO_ROI has been set prior to performing an auto white shading, the white shading algorithm will be restricted to only using the portion of the image defined by the AUTO_ROI (which the user had previously defined on a ‘white’ area of the image).  

API Control

PxLGetFeature, PxLSetFeature

Feature Flags

Parameters