Unlike trichromatic human vision, birds are tetrachromats with the fourth UV cone. This paper discusses on "What spectra are visible to Peking robin?" Human can see the spectrum C*_A called "fundamental" extracted from the input spectrum C through Matrix-R_A. As well, Peking robin can see the fundamental C*_B extracted through the extended Matrix-R_B. Matrix-R_B is given by Peking robin's ROGU (Red Orange Green and UV) cone sensitivities. The super vision spectrum C*_B projected onto FCS (Fundamental Color Space) spans up to 300~400 nm UV range. The key is not to estimate the original hyper spectra but to restore the low-dimensional spectra called "fundamental", truly visible to the tetrachromat. The model doesn't take care the "metameric black" component but tries to predict the fundamental C*_B from sRGB camera images under D65. The fundamental C*_B can be restored if the input spectrum C is known, but not always. Since the fundamental C*_A without "metameric black" carries the unique tri-stimulus value T_A, it's mathematically recovered from T_A by "pseudo-inverse" projection. Hence, the fundamental C*_B must be recovered from the tetra-stimulus value T_B. The model predicts T_B from T_A based on the bold hypothesis that T_B (ROGU) will change interlocking to T_A (RGB) for the common scene. The fundamental C*_B is restored by the pseudo-inverse projection of predicted T_B. The paper verifies how the model recovers the fundamentals in comparison with the true UV flower's spectra and discusses how it works well or not.