Simple Deconvolution Tool
The Simple Deconvolution Tool is good for sharpening images with a minimum of effort. It is fast, easy-to-use and has several deconvolution methods, one of which will probably be a good match for your photo.
There are five deconvolution methods that you can choose from: Van Cittert, Jansen Van Cittert, Landweber, Lucy Richardson and Maximum Entropy. Van Cittert is fast, and Lucy Richardson and Maximum Entropy are good at suppressing noise.
Blur Kernel Settings
In this group you can define a blur kernel which will be used to sharpen your photo.
Blur kernel type: lets you set the blur kernel shape. Options are Guassian, Exponential, Lorentzian and Cauchy. The Lorentzian and Cauchy settings are particularly good at sharpening.
Blur kernel size: this sets the width (or sigma) of the curve used to make the blur kernel. Larger values have greater effect. For sharpening most images, a good starting point is usually in the range of 1.5 – 2.0.
This group allows you to set the parameters for running deconvolution
Iterations: the number of iterations to do. More iterations can lead to a stronger effect, but after a certain point the deconvolution algorithm with often converge, which means that doing more iterations after that point will have little effect. Usually 10 – 20 iterations are sufficient.
Deconvolution strength: only applies to the Lucy Richardson and Van Cittert deconvolution types. A higher value for the deconvolution strength will produce a stronger sharpening result.
Convert to linear pixel values: some file formats (like JPEG) apply a gamma curve to a photo. This can be undesirable when doing deconvolution as it can reduce the effectiveness of the deconvolution algorithms. When this setting is checked, the image is converted back to linear pixel values by undoing the effect of the gamma curve.
Aggressive: only applies to the Lucy Richardson deconvolution type. When checked, the deconvolution will be accelerated so less iterations are required. However, this mode is not good at noise suppression, so it should be used carefully.
Suppress halos: when checked, an estimate of the location of halos (or artefacts) will be done and then an attempt will be made to mitigate their effects. This can result in a more natural looking result in some circumstances.