function [ error_per_image, err_pp, err_pp_dim, frontal_ids ] = compute_error_small( ground_truth_all, detected_points_all )
%compute_error
%   compute the average point-to-point Euclidean error normalized by the
%   inter-ocular distance (measured as the Euclidean distance between the
%   outer corners of the eyes)
%
%   Inputs:
%          grounth_truth_all, size: num_of_points x 2 x num_of_images
%          detected_points_all, size: num_of_points x 2 x num_of_images
%   Output:
%          error_per_image, size: num_of_images x 1


num_of_images = size(ground_truth_all,3);
ground_truth_all_orig = ground_truth_all;

ground_truth_all = ground_truth_all([1:60,62:64,66:end],:,:);
ground_truth_all = ground_truth_all(18:end,:,:);

num_of_points = size(ground_truth_all,1);
frontal_ids = true(num_of_images,1);

if(size(detected_points_all,1) == 68)
    detected_points_all = detected_points_all([1:60,62:64,66:end],:,:);
    detected_points_all = detected_points_all(18:end,:,:);
end

error_per_image = zeros(num_of_images,1);
err_pp = zeros(num_of_images, num_of_points);
err_pp_dim = zeros(num_of_images, num_of_points, 2);

for i =1:num_of_images
    detected_points      = detected_points_all(:,:,i);
    ground_truth_points  = ground_truth_all(:,:,i);
    visible = ground_truth_points(:,1) > 0;
    ground_truth_points_orig = ground_truth_all_orig(:,:,i);
    visible_orig = ground_truth_points_orig(:,1) > 0;
    
    if(sum(visible_orig) < 55)
        frontal_ids(i) = false;
    end
    
    normalization_x = max(ground_truth_points_orig(visible_orig,1)) - min(ground_truth_points_orig(visible_orig,1));
    normalization_y = max(ground_truth_points_orig(visible_orig,2)) - min(ground_truth_points_orig(visible_orig,2));
    normalization = (normalization_x + normalization_y)/2;
    
    sum_c=0;
    for j=1:num_of_points
        if(visible(j))
            sum_c = sum_c+norm(detected_points(j,:)-ground_truth_points(j,:));
            err_pp(i,j) = norm(detected_points(j,:)-ground_truth_points(j,:));
            err_pp_dim(i,j,1) = detected_points(j,1)-ground_truth_points(j,1);
            err_pp_dim(i,j,2) = detected_points(j,2)-ground_truth_points(j,2);
        end
    end
    error_per_image(i) = sum_c/(sum(visible)*normalization);
    err_pp(i,:) = err_pp(i,:) ./ normalization;
    err_pp_dim(i,:) = err_pp_dim(i,:) ./ normalization;
end

end