Postrectification

Postrectification refers to a processing step applied after an initial rectification operation, typically in image processing or signal processing. Rectification itself is a process that converts all negative values in a dataset to positive values, effectively mirroring the negative portion of the data onto the positive axis. This is commonly used to represent the magnitude of a signal or the absolute difference between values.

Postrectification involves performing further operations on the data that has already undergone this initial rectification. The specific nature of the postrectification step depends heavily on the application. For instance, in image processing, after rectifying pixel intensity values (e.g., to ensure all values are non-negative), a postrectification step might involve applying a logarithmic transformation to compress a wide dynamic range of intensities, or a normalization process to scale the values to a specific range.

In signal processing, after rectifying a waveform to obtain its envelope, postrectification might involve smoothing the resulting signal using a low-pass filter to remove high-frequency ripple and obtain a cleaner representation of the signal's amplitude. This is often a crucial step in applications like demodulation or amplitude measurement. The purpose of postrectification is to refine or further transform the rectified data to make it more suitable for subsequent analysis, interpretation, or display, addressing limitations or enhancing desired characteristics of the initial rectified output.