How can I avoid reading other objects?
This is a difficult question to answer without knowing more about what you are trying to do and how your warehouse is set up. If you are attempting to read items in one area and not another, using a handheld RFID reader might work. It might also be possible to put up screens to block RF signals from leaving one area of the warehouse and reaching tagged items in another warehouse.
If the items are right next to one another on a shelf and you want to read the tagged product on the left but not the one on the right, that is going to be difficult. The best approach would be to use software to filter the reads. Let's say you have a warehouse filled with metal tire rims and would like to take an inventory count of all 16-inch rims, but you don't care about the 18-inch rims at the moment. You could use software to generate a list of items you believe to be in the warehouse and then use a handheld (or perhaps fixed overhead readers) to interrogate all tags in the environment. The software would then match the unique ID numbers in the database associated with each item and let you know how many were found. The software would provide a list of 16-inch rims not found, as well as a list of 16-inch rims found that weren't expected to be. It would ignore all serial numbers on 18-inch rims.
The reality of any RFID system is that you are going to need to perform this kind of filtering. That's because the reader will likely interrogate the same tag several time, perhaps hundreds of times, during an inventory count. So software needs to be able to say "Yes, we've seen this item" once the tag has been read, and then ignore additional reads of that same tag during a single cycle count.
—Mark Roberti, Founder and Editor, RFID Journal