Self Plagiarizing Artist

I came across this artists site the other day, and it got me thinking yet again about plagiarism.
If you did not know the first series of fingerprints, for example, were all taken by the same artist, you would call it plagiarism. But what if you see this idea and come up with a concept of your own, say using spaghetti. Is that plagiarism?
This site at least credits the originals, so I guess that is not plagiarism...
I decided that it was time to get a definition of this plagiarism concept...

Plagiarism is the unauthorized use or close imitation of the language and thoughts of another author and the representation of them as one's own original work. Unlike cases of forgery, in which the authenticity of the writing, document, or some other kind of object, itself is in question, plagiarism is concerned with the issue of false attribution.

(from wikipedia)

It is also interesting to note that this definition and the concept behind it are under dispute.

From my understanding, almost all the issues of plagiarism deal with the written word. Taking a quote out of context, publishing another authors work, etc.

But back to my opening argument. Since the first photographer mentioned above did a series of images relating science to unrelated physical objects, no one else can do this ever again? How sad. And further to that, if you had never seen these photos and you created something similar, how can you be held responsible for plagiarism?
I argue that as human beings living in a society where communication is only getting wider and more open, we almost always use ideas of others to build up our own, either consciously or not.
Back to photography, when you are shooting an image (here the term shooting includes pre-visualization, image design/creation, or any other term used by other photographers through the ages, and for that matter artists back even farther...) do you not try to remember how other photographers/artists have approached similar problems? Use other peoples ideas and concepts to enhance your own approach? I don't think there is an artist of any medium who has not studied his peers and the masters of his craft. That is how we learn.
I guess my problem is that I don't see a clean separation between learning from past masters, homage to past masters, and stealing from past masters. Maybe I see plagiarism as a whining,"you took my idea and did it better, how dare you" or "my interpretation is better than yours, nyah nyah"
If someone were to take one of my photos and improve on what I was trying to say, I would be honored (I am tempted to bold, highlight, and set neon lights around "improve") All I ask is that they show me the work afterwords so I, in turn, can learn from them.
Ooohhh, THAT is what plagiarism is:

Plagiarism is the using of ideas without respect or honor for the people who helped you get past certain problems

Ok, I guess now I should start my list of people who have influenced my photography... on second thought, it would sound too much like an Oscar acceptance speech... I know who you are... Thanks