Fig. 1. Miniature spectral detection. (a) Schematic diagram of the working principle; (b) Schematic diagram of numerous micro-spectrometers; (c) Schematic diagram of a single micro-spectrometer and transmission spectrum of a metasurface

Fig. 2. Design of the metasurfaces. (a) The unit cell of the metasurfaces; (b) Schematic diagram of a single micro-spectrometer; (c) Schematic diagram of the selection of metasurfaces according to different average correlation value intervals; (d) Transmission spectra of different patterns of the metasurfaces

Fig. 3. Flow chart of our proposed methodology and traditional methodology

Fig. 4. The reconstruction fidelity produced by different metasurfaces selection design methodologies in Table 1. (a) Spectrum 1~5 in Table 1; (b) Spectrum 6~10 in Table 1; (c) The reconstruction fidelity produced by different metasurfaces selection design methodologies under spectrum5; (d) The reconstruction fidelity produced by different metasurfaces selection design methodologies under spectrum10

Fig. 5. Spectral characteristic simulation verification. (a) Incident spectrum and the reconstructed spectrum with a central wavelength of 560 nm and a bandwidth of 1.8 nm; (b) Enlarged images around the central wavelength in Fig. 5(a); (c) Spectral resolution simulation verification with a central wavelength interval of 2 nm; (d) Spectral resolution simulation verification with a central wavelength interval of 3 nm; (e) Reconstruction spectrum and reconstruction fidelity of broadband spectrum 1 under different number of structures M; (f) Reconstruction spectrum and reconstruction fidelity of broadband spectrum 2 under different number of structures M

Fig. 6. Image spectral signals perception verification. (a), (b) Original and reconstructed image spectral signals respectively^[46]; (c) Reconstruction fidelity of spectral signals generated by different metasurface design methods under different color blocks. The reconstructed spectrum 1 is produced from the metasurface structures selected using the average correlation value interval [0.1~0.3], and the reconstructed spectrum 2 is produced from the randomly selected metasurface structures