Tunnel　images　are　affected　by　the　shooting　environment,　and　there　are　problems　such　as　uneven　light　distribution,　local　occlusion,　and　more　noise,　etc.　Aiming　at　the　overexposure　and　distortion　of　the　existing　image　enhancement　algorithms　in　the　optimisation　process,　we　propose　a　tunnel　image　enhancement　algorithm　DNO-SCI　(denoising　and　overexposure　suppression　based　Self-Calibrated　illumination).　Firstly,　based　on　the　SCI　model,　a　noise　suppression　module　based　on　a　priori　knowledge　is　added　to　effectively　suppress　the　noise　of　SCI　after　low-light　enhancement.　Secondly,　overexposure　suppression　is　guided　through　the　Y　channel,　and　finally　a　lightweight　self-calibrated　tunnel　construction　image　enhancement　algorithm　is　proposed　in　combination　with　depth-separable　convolution.　Experimental　results　demonstrate　that　the　proposed　image　enhancement　algorithm　can　effectively　enhance　tunnel　construction　images　with　uneven　brightness　and　suppress　local　overexposure.　©　2024　SPIE.