with which tool can i do that?
1. Use Interpolate shape tool. This tool extracts the raster values and assign to line.
http://resources.arcgis.com/en/help/main/10.2/index.html#//00q90000006m000000
2. Now use Split line at vertices tool.
http://resources.arcgis.com/en/help/main/10.2/index.html#//00170000003z000000
3. Then Use the splited line as input in Feature to Point tool (point_location = Centroid)
http://resources.arcgis.com/en/help/main/10.2/index.html#//00170000003m000000
4. Finally use Extract by points tool to extract the pixels below the line.
http://resources.arcgis.com/en/help/main/10.2/index.html#//009z0000002p000000