⚠ NormalHeight has merged into DeepBump, please use DeepBump instead. ⚠
NormalHeight is a Blender add-on to compute depth from normal maps. It uses the Frankot-Chellappa depth-from-gradient algorithm. It can be used in conjunction with DeepBump to produce height maps from single pictures.
Download the repo as a ZIP, then in Blender go to Edit -> Preferences -> Add-ons -> Install and select the downloaded ZIP file. Then enable the add-on.
In the Shader Editor, select a normal map Image Texture Node and click Generate Height Map in the right panel under the NormalHeight tab.