Solving for Unknown Values in Overlaid Grids

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The discussion revolves around solving for unknown values in a fine square grid (blue) using the averages from two overlaid coarse grids (red and green). The red grid contains averages of the blue values, while the green grid, displaced by (+1,+1), also represents averages of the blue values it obscures. Participants conclude that it is likely impossible to derive the blue values from the given grids due to the insufficient number of equations relative to the unknowns, particularly in smaller grid configurations like 2x2 or 3x3.

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phil_drew
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Hi All,

I wonder if you can help me with a little puzzle I'm working on. I'll include a picture for clarity. I suspect that you mathsy types will be able to tell me straight away if this is possible or not, but I just can see the obvious...

I have a fine square grid of numbers (blue in the picture), but I do not know the values of the numbers. I also have, overlaid (red in the picture), a more coarse-grained grid of numbers which are the averages of the four numbers they lay ontop of.
I then have another identical large grid (green in the pic) which is displaced by (+1,+1) small grid points. Its values are also the averages of the blue values it obscures.

My question...
If I know all the red and green values (averages of underlying data set), can I work out the blue values? If it can be done, it will no doubt result in a huge string of simultaneous equations. If somebody could start me off by showing how a small section of this could be done, I'd be very grateful. Or if it's impossible, could somebody tell me why?
Would it help to have more large grids off-set by other amounts? The grids can extend a long way, and I'm not fussed about knowing ALL the blue numbers - if I can work my way out from the middle, I'll go as far as I need, then forget about the perifery.

Thanks for any help,
Phil
 

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simplify

I cannot answer your question but why don't you try that with a minimal grid ( is that 5x5) I'm not sure , that will limit the number of equations you will have to consider -- off the top of my head the number of equations must match the numer of unknowns do your two grids provide that ?? Ray
 
I@m struggling to picture it,even with that gif but:

as you cannot solve it in the degenerate case of a 2x2 grid, why should you be able to solve it for a larger one? think 3x3, at most you have 4 equations in 9 unknowns, possibly, could you provide a more detailed explanation?
 

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