It would be relatively easy to setup a CCTV rig that would monitor and report stress changes over time on bridges and such. Would be cheap and low maintainence.
All very doable, but I don't think this would work using a standard CCTV looking at an area bigger than a metre (few feet) across.
A long time ago in a place far far away, I was part of a team that did exactly this to differentiate between healthy and possibly pre-cancerous tissue.
How did those techniques pan out? Did patients ingest fluorescent dyes that got ingested and metabolized faster by cancerous cells, or do some types of cancer cells naturally fluoresce with a unique spectra you can detect?
Epithelial and endothelial cells only?
Seems it might be not-extremely-bright / pretty dark during such intervals.
From experience in actually building reinforced concrete structures (both bridges and tunnels) and following later checks/inspections the amount of dirt (be it smog, pollution, dust, spiderwebs, whatever) on a structure that has been built only a few years before is impressive and would probably make this kind of microcracks detection not feasible/ineffective, let alone via a camera (or a drone).
Typically (talking of box girders where you could walk inside the bridge) you would normally check areas where you would suspect a (macro) crack to possibly develop by brushing with a hard brush the area and (not always, but it happened) pressure wash it.