Scanned interferograms obtained with PIONIER on the high SNR regime (left) and the low SNR regime (right) and using the spectral dispersion of 7 channels across the H-band. An example with the baseline with the lowest frequency is represented here. The bottom black signal represents one output of the combiner for the central spectral channel (i.e. one pixel of the detector), versus the optical path difference in the scan. The large temporal coherence and the photometric fluctuations are clearly visible. The top red signal represents the subtraction of two conjugate outputs, after averaging the 7 spectral channels. The SNR is enhanced and the photometric fluctuations are almost perfectly removed.