Question

Which of the following statements in the context of image-to-image registration is/are CORRECT?

• A. The images may belong to different dates
• B. The images have significant overlapping geographic area
• C. The images must have the same spatial resolution
• D. The images must belong to the same dates

Hint:

Registration only needs enough common ground area to place tie points; it does not require the same acquisition date or the same pixel resolution.

Answer 1

The Correct Option is A, B

Step 1: Define image-to-image registration.
Image-to-image registration is the process of geometrically aligning two or more images of the same area, taken possibly by different sensors, at different times, or with different viewing geometries, so that corresponding ground features occupy the same pixel location in all images.

Step 2: Check option (A) - different dates.
Registration is very commonly performed between images acquired on different dates, for example in change detection or multi-temporal crop monitoring, where one image is a before scene and the other an after scene. There is no requirement that dates match, so this statement is correct.

Step 3: Check option (B) - overlap requirement.
For registration to be possible, the two images must share a significant common ground area, because tie/control points are picked from features visible in both images to compute the geometric transformation between them. Without sufficient overlap there are not enough common features, so this statement is correct.

Step 4: Check option (C) - same spatial resolution.
Images from different sensors (coarse multispectral vs fine panchromatic) are routinely registered together; resampling during registration brings them onto a common grid. Identical native resolution is not required, so this is false.

Step 5: Check option (D) - same date requirement.
Same-date acquisition is not required; many key registration applications specifically need different-date imagery, so this is false.

Step 6: Conclusion.
Only statements (A) and (B) are correct. \[ \boxed{\text{Correct: (A) different dates allowed, and (B) significant overlap required}} \]