When more than one dye is used, a necessary preprocessing step is to unmix the channels and recover an estimate of the pure dye-specific intensities.
Head motion correction is another common preprocessing step.
On the other hand, machine learning also employs data mining methods as "unsupervised learning" or as a preprocessing step to improve learner accuracy.
Because those lack structural interpretation ability, the preprocessing steps face a feature selection problem (i.e., which structural features should be interpreted to determine the structure-activity relationship).
As a preprocessing step, for each object (in our example, and ) we will calculate a hierarchy of bounding volumes.
This means that they can be compiled directly into an application without any preprocessing steps, but it also makes them far larger than their raw pixel data.
Still the preprocessing step of mesh generation remains a sequential bottleneck in the simulation cycle.
Like other feature detectors, the Hessian affine detector is typically used as a preprocessing step to algorithms that rely on identifiable, characteristic interest points.
Thus variable selection is often required as a preprocessing step on the data before algorithms used to find the best dynamic treatment regime are employed.
It often is used as a preprocessing step for other algorithms, for example to find a starting configuration.