Effect of Resizing (Up Scaling) an Image on the Ability to Detect / Recognize Objects I work in a research lab and am currently setting up a system to image objects approximately 30 microns in diameter with a 250x USB microscope, then use image subtraction to isolate the objects as they move past the microscope FOV, and use blob detection to detect the object's presence in the binary subtracted image.

The microscope can capture still images at 1280x720, but video can only go up to 640x480. Ideally I wanted to take rapid still images (~10 FPS) at 1280x720, but various issues are preventing me from doing that. Capturing rapid images at 640x480 on the other hand is easily doable, but I'm not sure if the images would be clear enough for the image processing to resolve the objects at that resolution. 

Would capturing the images at 640x480, then resizing them to 1280x720 before processing them, improve the ability to detect/resolve the objects in the image?
It is theoretically impossible to add information by increasing the resolution of an existing image.

So from that point of view -- no.

However, I certainly find it conceivable that if you're using some canned algorithms they may be sensitive to pixelation.  Unless they're really lame, I would only expect this to be an issue if your original images are very sharp -- if the un-differenced objects tend to have blurry edges, either because of the limitations of your microscope or the properties of the objects themselves, then I'd think about trying what you suggest.

Otherwise -- you can't get something for nothing!