If a line signal has only one dimension, like in spectrometry, the  binning can also improve the signal to noise ratio. The lines are  summed vertically in the chip. That leads to a higher signal level  by the same read noise. The software is capable of selecting a range of lines for a partial binning. That means that those areas of the sensor which have no optical signal can be omitted and only the lines of interest are used for the sampling. All other lines  are discarded. All area sensors from Hamamatsu (FFTs) can be used in this binning  mode (see spectroscopy). Also the EM sensor TC253 can be used in this binning mode (see EM).

Shown here is a spectra sampled with a TC253 sensor from TI. The sensor has 656 x 496 pixel with em- amplification and free adjuastable binning. It is a 100 times amplificated HG line spectra (green line and yellow double line).