This method allows you to improve images in which the quality has been impaired by uneven illumination or vignetting.

If you want to perform shading correction before an experiment (recommended), you have to use the shading correction function in the Camera tool, in the Post Processing Section.

Parameter

Description

Shading Mode

Selects which shading correction should be applied.

-

Channel Specific

For multichannel references, the information from each channel is applied individually to the input image. The number and type of channels must be the same between input image and shading reference image. This is the correct setting when using a reference image which was created by the Shading Reference for Processing function (e.g. for Axioscan images).

-

Averaged

For multichannel references, an average over all channels is calculated and then applied equally to each tile of each channel. This should ensure that a good result can still be achieved with an unequal number of channels or different channel characteristics.

-

Tile Specific

In case a shading reference has more than one tile, the tiles of the reference and the tiles of the image that should be corrected are mapped to each other. The tiles must be identical in number and XY position. This can be the case, for example, when using an Axiozoom where shading is primarily determined by the sample mounting situation rather than the optical system.

Automatic

Activated: The function automatically calculates the reference image for shading correction from the input image.

Shading Reference

Only available in Batch mode and if Global Shading is selected, or Camera Shading is selected and Automatic is deactivated.

Enables you to select a reference image for the shading correction.

Display Mode

-

Additive

In this mode the normalized reference image is subtracted from each camera frame. This influences the brightness of the image.

-

Multiplicative

In this mode each camera frame is divided by the normalized reference image. This influences the contrast of the image. This is the default setting.
The simulated/auto reference image is created by averaging up to 20 camera frames in the input image and running a lowpass filter on them.

Offset

Adjust the gray value that will be added on to the newly calculated gray values using the slider or input field. If this results in negative values, these are set to 0. Values that exceed the maximum gray value are set to the maximum gray value.