What is a maximum filter response in MR8 filter bank?

Question

So I am implementing The Maximum Response (MR) Filter Bank - MR8. I am using this as a reference: http://www.robots.ox.ac.uk/~vgg/research/texclass/filters.html

And so far I have written the 38 filters, but have no idea how to compute the maximum filter response from the 6 rotations of each edge and bar filter variations.

1. What is a filter response? Is it the result from the filter application or something else?

2. What is a maximum response?

3. How to compute the maximum responses for the edge and bar filters?

Answer 1

1. Suppose you have a filter f and an image I. Filtering I with f is a straightforward convolution of I and f. Let's say the filtered image is I_f. The response of the filter f at a pixel (x,y) of I is then I_f(x,y).

2. Now, you have a number of oriented filters f1, f2, f3, ... Consequently, you will have filtered images I_f1, I_f2, I_f3, ... From these you construct a maximum response image I_f_max as:

   I_f_max(x,y) = max (I_f1(x,y), I_f2(x,y), I_f3(x,y), ...)

   Therefore, from the application of 6 oriented filters, you have constructed a single response image, which takes into account only the maximum filter response at each pixel and discards the rest.

3. 1 and 2 should answer this.