The Line Cutout Service is a utility service that can automatically detect written lines in (parts of) scanned documents. The user can upload a document image and select a rotated rectangle containing written lines. The service returns cut out line images and the bounding boxes of these images representated as Open Annotations. The user can than use this information as she likes, for example in the context of an efficient line-by-line transcription tool.
Sources are available on GitHub. Note however that these sources do not include the image processing software that is used.
An online version is available here.