Understanding "InitialRadius" and "Epsilon" size-parameters in pixels (of OnePlusOneEvolutionary optimizer for multimodal image registration)

In the help for "OnePlusOneEvolutionary" optimizer the parameters "Epsilon"and "InitialRadius" is decribed as follows:

Epsilon — Minimum size of the search radius

1.5e-6 (default) | positive scalar

Minimum size of the search radius, specified as a positive scalar. Epsilon controls the accuracy of convergence by adjusting the minimum size of the search radius. If you set Epsilon to a small value, the optimization of the metric is more accurate, but the computation takes longer. If you set Epsilon to a large value, the computation time decreases at the expense of accuracy.

InitialRadius — Initial size of search radius

6.25e-3 | positive scalar

Initial size of search radius, specified as a positive scalar. If you set InitialRadius to a large value, the computation time decreases. However, overly large values of InitialRadius might result in an optimization that fails to converge.

However, it is not clear to me how to relate these to the actual size in pixels. Please clarify, as I know my criteria in pixels.

[Luuk Heijnders]

Made a mistake, I now understand better. The optimizer adjusts the parameters based on the metrics. Metric is between 0 and 1. Transformation parameters will be adjusted. So no link to the image is present.