Tone Mapping image manipulation
First, I have to say that you are using good variable names.

Turn Option Strict On

This setting is important, it'll help you see errors and needed conversion.

You'll notice that this isn't possible


Dim LaLs = LinearAngleTextBox.Text * LinearStrengthTextBox.Text



But instead you need to convert it to integer.

Dim LaLs = Int32.Parse(LinearAngleTextBox.Text) * Int32.Parse(LinearStrengthTextBox.Text)


Don't repeat yourself

You'll then notice that some conversions are done often.


Int32.Parse(LinearStrengthTextBox.Text)



Put these in proper variable right at the begining.

Dim linearStrength As Integer = Int32.Parse(LinearStrengthTextBox.Text)


There are formula like the below that are done in the inner loop, which can be moved outside of the loop.

(x * Image.GetPixelFormatSize(bmpData.PixelFormat) / 8)