Showcase for the D⁴PO algorithm to denoise, deconvolve, and decompose multi-domain photon observations. This is a simplified test scenario, which disregards a potential background flux and has only a unit response function (a perfect PSF). Top panels: (from left to right) data, providing spatial versus spectral information about each detected photon, original multi-domain point-like flux, as well as the multi-domain diffuse fields. Bottom panels: reconstruction of both fields. All fields are living over a regular grid with 350 × 350 pixels.