Single drivers do not really image coherently. IM distortion from moving at largely different frequencies ruins perceived cohesiveness, not to mention different parts of the speaker behaving different at different frequencies.
Imaging in most recordings is purely conceptual. It is manufactured. Most live recordings have nothing remotely like imaging either with very odd exception and even then. That makes left-right manufactured, and depth to pretty much. Height? It is not there. It just is not in the recording.
Audiophiles will convince themselves of a million reasons why "imaging" is better or worse, right down to fuses. It makes me laugh. Imaging is almost exclusively your room and your speaker and of course the recording. Really awful electronic can impact imaging, but we are talking last bit, and most people are not remotely there.
Want pinpoint imaging .... go into an anechoic chamber or wear heaphones. I know, not the answer you were looking for. Headphones are better, but an anechoic chamber can be a good substitute. Sound a bit like crap though.
So, can you measure imaging? No, but you can measure that impact of the speakers, room and electronics on what reaches the ears and get a relatively good impression of what the likely imaging is like. What I can’t tell you is whether you will like it. It is a trade-off between imaging and ambience in the real world with speakers.