I want to calculate the total length of edges in a Voronoi diagram like this
I can calculate this with
lengths = RegionMeasure /@ MeshPrimitives[VoronoiMesh[pts], 1]; Total[lengths]
but, I want to eliminate from the calculation the diagrams touching the border of the image. I can select this diagrams like here
and I can keep with the orange diagrams
but I don't know how to calculate the total length of the edges of the last graphic. Any suggestions?