I've got a large 1 meter by 2 meter pattern printout for a garment. I'm not able to capture fine detail with a single shot, namely the sensor on my camera captures poor detail at distances past a certain threshold. This being the case, I'd like to take multiple close-up shots to, shot by shot, capture the entire printout. With these shots I'd then like to merge them into a single detail-preserved "shot," as it were. Perhaps someone here might know of an opensource program that meshes the images based on pixel geometry--or some such similar method. I'm aware that this technique is used in remote-sensing of farmland at low altitudes. A camera attached to a weather balloon or remote-controlled plane is sent up with a camera programmed to take shots every so often. After the data is retrieved, it is merged into a single image of the area.
Hugin can do this. The only tricky part is that you need to choose the correct optimizer setting ("positions and translation") to tell Hugin that your camera has moved between shots.
Here are a couple of tutorials for using Hugin like this:
Microsoft ICE (Image Composite Editor) is free (can be downloaded from here) and can perform the task you describe (and many more).
IMO, using Photoshop to manually stitch several photos together is probably going to be the most accurate, precise way of achieving this. Automatic photo stitchers aren't anywhere close to perfect, and though it will take a ton of time, manual Photoshopping is probably the best choice. Especially if the end result is for a professional sale.