Image channel operations

Channel operations manipulate the layered structure of multi-channel images without changing the underlying intensity values. Extract channel pulls a single named or indexed channelLoading... from a multi-channel input and returns it as a single-channel grayscale imageLoading.... Extract strongest channel picks, per pixel, the channel with the highest value and writes that value to the output — useful for visualization composites, less so for quantitative measurement. Set channels to RGB takes three grayscale inputs and bundles them as the R, G, B channels of a new RGB image. Swap channels reorders the channel sequence of an existing multi-channel image. None of these change the pixel-level intensity data; they change which slice of it the next engine receives.