Hi, in binary image i want to divide 'n' number frames into n/2,then in both n/2 frames, i need to calculate number of white pixels,check if that counts are larger or smaller than 'n' white pixels count.if greater again follow the same steps.

its like divide and conquer strategy,if suppose the second 'n/2' white pixel count is greater then divide it into two half and so on.Otherwise find which frame contain maximum white pixels and save it separately in array. please help me sir using matlab code

[Walter Roberson]

Take the example image of ones(6,10) and n = 3, and show us how you would want that to be divided up.

[kaavya subramani]

1. suppose video contains 100 frames.
2. find count of '1'(white pixel)in all 100 frames.
3. split 100 frames into 50 and 50.
4. calculate '1s' in both 50 and 50 frames.
5. if number or count of '1s'in first 50frames are lesser than number of '1s' in 100 frames,then find a frame which contain maximum '1s'from that 1st 50 frames and store it separately,else again divide it and compare with first 50 frames.
6. likewise follow for 2nd 50 frames and so on

[Walter Roberson]

The count of 1s in the first 50 frames is always going to be less than the number of 1s in all 100 frames -- unless, that is, that the last 50 frames are all completely 0 in which case the count of the first 50 would exactly equal the count for all 100.

Do you ever divide further than into groups of 25? If you do then you have the problem that 25 is not evenly divisible by 2: do you want to divide into half-frames? If you do then you still have a problem if the number of pixels in the frame is odd, such as for a 101 x 137 frame.

[kaavya subramani]

I understood what you commented sir 1.number of 1s in 100frames/ 2 or 4 and then compare with result of 50 frames.if greater then i want to divide that number of 1s in 50frames/ 2 or 4. 2.if suppose 25 frames use ceil or floor. 3. i changed my video to have even number of pixels as my initial step

[kaavya subramani]

Also i changed my video into same dimension.eg 192x192

[Walter Roberson]

If I understand correctly, you want your routine to take as input a group of frames. It should divide the group into two halves. The half that has more than half of the total white pixels should be sub-divided, and the half that has the most pixels out of that should be selected. But should that quarter then be sub-divided as well? Does the process keep going until you are at the point where the two halves have exactly the same number of white pixels or the point where you are down to one frame?

The collection to pass in should be either a struct array or a cell array for the following code to work

function split_collection = splitwhite(frame_collection)
  if length(frame_collection) == 1
    split_collection = frame_collection;  %got down to one frame
    return
  end
  firsthalf = frame_collection(1:end/2);
  secondhalf = frame_collection(end/2+1:end);
  first_white = number_of_white(firsthalf);
  second_white = number_of_white(secondhalf);
  if first_white > second_white
     split_collection = {splitwhite(firsthalf) secondhalf};
  elsif first_white < second_white
     split_collection - {firsthalf splitwhite(secondhalf)};
  else
     split_collection = frame_collection;  %no split if the two halves are the same
 end
end

[kaavya subramani]

The process should continue until we get white pixels count less than its parent.i attached one example diagram sir,please see it

[kaavya subramani]

u r right,want to take total frames as input and procees

[kaavya subramani]

if first_white > its parent/2,not second white sir.

[kaavya subramani]

help me sir.Thankyou

[Walter Roberson]

Let P = A + B . If A > P/2 then A > (A+B)/2 so A > A/2 + B/2 so (A-A/2) > B/2 so A/2 > B/2 so A > B.

Therefore the test for the first half being more than half of the total group is the same as checking to see if the first half is more than the second half.

Side note: old-time volunteers who have not had enough sleep tend to remember http://boards.straightdope.com/sdmb/showthread.php?t=359127

[kaavya subramani]

what is this sir?

[Image Analyst]

Are these video frames you're talking about, or subimages of a single image? Are you trying to do quadtree decomposition? http://www.mathworks.com/help/images/ref/qtdecomp.html?s_tid=srchtitle

https://en.wikipedia.org/wiki/K-d_tree

https://en.wikipedia.org/wiki/Median_cut

[kaavya subramani]

i am talking about video frames sir

[Walter Roberson]

What does the "this" refers to that you are asking about?

My first line is a proof that testing that the first half holds more than half of the total is the same thing as testing that the first half holds more than the second half.

My final line was a reminder that volunteers sleep on their own schedule, not at times arranged to be convenient for you. The volunteers in North America who regularly answer questions are in GMT-4, GMT-5, and GMT-6

[kaavya subramani]

ok sir