Hugin is a imaging utility than can stitch images into panoramas. In short, you can join overlapping pictures into one. But Hugin supports a lot of fine-grained powerful operations, more than what meets the eye! Here are some of those:
- Stitching multi-row photos together
- Simulating an architectural projection
- Stitching photos from different lenses
- Stitching flat scanned images
- Stitching murals-mosaic mode
- Perspective correction
- Simple lens calibration
- Using blend masks
- Stitching auto-exposed panoramas
- Surveying buildings
- And many more…
Hugin is multiplatform, free and open source.
Webpage: Hugin