Fig. 1. Typical global rainbow curves under two wavelengths: (a) distributions of the light intensity on the pixel number and (b) distributions of the light intensity on the scattering angle by calibration.

Fig. 2. Simulated RMS errors between the preset refractive indices and the ones from the rainbow signal inversion with different preset values of RI and a preset temperature for the deionized water spray under two wavelengths (532 and 632.8 nm) at 25°C (RI=0.47).

Fig. 3. Optical setup of the self-calibrated global rainbow system.

Fig. 4. (a) Original global rainbow image of a spray of deionized water and images of separated dual-wavelength signals under the wavelengths of (b) 532 and (c) 632.8 nm.

Fig. 5. Global rainbow curves of a spray of deionized water: dual-wavelength distributions of scattered light intensity.

Fig. 6. Polychromatic global rainbow images of ethanol-water solutions with volume concentrations from 10% to 60% in steps of 10%.

Fig. 7. Comparison of the measured refractive index by the methods of mirror calibration and self-calibration with the theoretical data for the ethanol-water solutions at 20°C.