find a table in onother table by 80%

hello everyone i have a table K2 50 X 50 that has 0 and 1 and a bigger table A 4864 X 3404.i want to find if table K2 is in table A(the elements of the table ) by a threshold of 80%.i have to search in the big table but how i scan all the 50 X 50 tables exists? thanks a lot

Answer 1

[Sean de Wolski]

You could do this with two calls to conv2():

A=[1 0 1];
V=[1 1 1 1 1 0 0 1 1 0 1];
small_matrix = A;
big_matrix = V;

xbig = logical(big_matrix);
xsmall = logical(small_matrix);
Xmorethan80 = (conv2(double(xbig),double(xsmall),'valid')+...
  conv2(double(~xbig),double(~xsmall),'valid')) > (numel(small_matrix)*.8)

I do not get the error you are describing with the above.

[Konstantinos Kontos]

i had the error ?? Undefined function or method 'conv2' for input arguments of type 'char'. Sorry but i dont know any good matlab code if thew answer is so obvious.

[Sean de Wolski]

If you have your two matrices and you name them big_matrix and small_matrix and they are binary values, the above should work.

[Konstantinos Kontos]

the 2 matrices are fotos that i binarized them first.i try it in onother pc and has the same error.if you find why pls let me know,thanks anyway!!

[Sean de Wolski]

Apparently they're not numeric if you're getting that error. Why don't you post small sample matrices.

[Konstantinos Kontos]

i try it with A=[1 0 1] and V=[1 1 1 1 1 0 0 1 1 0 1] but i had the same error .

When i put out the argument 'valid' and run it again i have ??? Undefined function or method 'conv2' for input arguments of type 'logical' so maybe there is the error.

[Konstantinos Kontos]

there are for sure binary cause when i print the matrices has only 0 ,1 values

[Sean de Wolski]

Try the editted version (wrap double() around everything)

[Konstantinos Kontos]

No unfortunately the same error. And i was so glad when i see the quick answer!!

[Sean de Wolski]

It works with the matrices you provided. See update.

[Konstantinos Kontos]

yes it works with my real matrices too,but i can not undterstand the result.how can i see if the small matrix is in the big by 80%?Thanks for the help !!!!!

[Sean de Wolski]

Anywhere were this a 1 means that the small matrix centered on that pixel ion the big matrix has an >=80% equality.

[Sean de Wolski]

find(Xmorethan80)

will tell you the linear indices directly.

[Konstantinos Kontos]

i see the results with the imshow but i dont know if is the correct cause i see black pixels there that o didnt expected.Furthermore if i want to see if the table exactly is on the other table, just erase the *.8?

thanks again you are really great!!

[Konstantinos Kontos]

where i see white pixels is that it found the small matric to the bigger?