how many membership functions have to be created for 10 sets of data where each data contains 4 sub sets?

i have three columns for a data. the data is the feature(lenth and breadth) of an image. if the length is 12.2 and breadth is 4.0 then the result will be 1 as shown below.

12.2 4.0 1

12.6 4.3 1

12.3 4.4 1

12.0 4.5 1

13.6 3.0 0

11.4 6.2 0

11.6 6.8 0

16.0 5.0 0

this is for a single image. likewise i have 10 images. in FIS (mandani)how many membership functions to add? for a single image i get the answer because i can set the input range. different images have diferent range. how to define the structure?