Inp1=rgb2gray(imread('D:visionImagesc11.ppm'));
figure, imshow(Inp1), title('Input image 1');
num_bins = 32;
A = imhist(Inp1, num_bins);
srcFiles = dir('D:visionImagesc1*.ppm');
B = zeros(num_bins, 30);
ptr=1;
for i = 1 : length(srcFiles)
    filename = strcat('D:visionImagesc1',srcFiles(i).name);
    I = imread(filename);
    I=rgb2gray(I);
    B(:,ptr) = imhist(I, num_bins);
    ptr=ptr+1;
end

% histogram intersection
a = size(A,2); b = size(B,2);
K = zeros(a, b);
for i = 1:a
  Va = repmat(A(:,i),1,b);
  K(i,:) = 0.5*sum(Va + B - abs(Va - B));
end

num_images = 30;
sims=K
relevant_IDs = [1 2 3 4 5 6 7 8 9 10];
num_relevant_images = numel(relevant_IDs);
[sorted_sims, locs] = sort(sims, 'descend');
locations_final = arrayfun(@(x) find(locs == x, 1), relevant_IDs)
locations_sorted = sort(locations_final)
precision = (1:num_relevant_images) ./ locations_sorted;
recall = (1:num_relevant_images) / num_relevant_images;
plot(recall, precision, 'b.-');
xlabel('Recall');
ylabel('Precision');
title('Precision-Recall Graph');
axis([0 1 0 1.05]);
grid;

function [out] = imcolourhist(im, num_red_bins, num_green_bins, num_blue_bins)

    im = double(im); %// To maintain precision

    %// Compute total number of bins
    total_bins = num_red_bins*num_green_bins*num_blue_bins;

    %// Figure out threshold between bins
    red_level = 256 / num_red_bins;
    green_level = 256 / num_green_bins;
    blue_level = 256 / num_blue_bins;

    %// Calculate which bins for each colour plane
    %// each pixel belongs to
    im_red_levels = floor(im(:,:,1) / red_level);
    im_green_levels = floor(im(:,:,2) / green_level);
    im_blue_levels = floor(im(:,:,3) / blue_level);

    %// Compute linear indices
    ind = im_blue_levels*num_red_bins*num_green_bins + im_green_levels*num_red_bins + im_red_levels;
    ind = ind(:); %// Make column vector for accumarray

    %// Determine 1D histogram - Ensure that every histogram
    %// generated has the same size of total_bins x 1
    out = accumarray(ind+1, 1, [total_bins 1]);
end

Inp1=imread('D:visionImagesc11.ppm');
num_red_bins = 8;
num_green_bins = 8;
num_blue_bins = 8;
num_bins = num_red_bins*num_green_bins*num_blue_bins;
A = imcolourhist(Inp1, num_red_bins, num_green_bins, num_blue_bins);

B = zeros(num_bins, 30);
ptr=1;
for i = 1 : length(srcFiles)
    filename = strcat('D:visionImagesc1',srcFiles(i).name);
    I = imread(filename);
    B(:,ptr) = imcolourhist(I, num_red_bins, num_green_bins, num_blue_bins);
    ptr=ptr+1;
end