Figure 2.

Overview of the human visual system’s response to a scene over the spectral range and over time.

The human visual system is responsible for facilitating image forming and non-image forming processes. For a given ‘pixel’ in each scene, a spectrum enters the eye and is focused by the lens onto the retina (a) where different classes of photoreceptors are activated: each class of photoreceptors produces an output signal which is assigned a weight and ultimately leads to observable changes in the observer (c). For that same ‘pixel’, a timeseries of hyperspectral images (HSIs) can be derived that represent the ‘spectral diet’ when projected onto the retina: at any instantaneous point in time t, a single HSI represents the visual stimulus over space spanned by the number of unique spectra coming from different direct and indirect sources (b).