Scales the intensities of all features using
$$\widetilde{x}_{ij}=\frac{x_{ij}-\overline{x}_{i}}{\overline{x}_{i}}$$
where \(\widetilde{x}_{ij}\) is the intensity of sample \(j\), feature \(i\) after scaling,
\(x_{ij}\) is the intensity of sample \(j\), feature \(i\) before scaling and \(\overline{x}_{i}\) is the mean of intensities of feature \(i\) across all samples
In other words, it performs centering (scale_center) and divides by the feature mean, thereby focusing on the relative intensity.