diff --git a/cvpr_computedescriptors.m b/cvpr_computedescriptors.m
index 0a0e419..63099be 100644
--- a/cvpr_computedescriptors.m
+++ b/cvpr_computedescriptors.m
@@ -22,10 +22,10 @@ OUT_FOLDER = 'descriptors';
 %% and within that folder, create another folder to hold these descriptors
 %% the idea is all your descriptors are in individual folders - within
 %% the folder specified as 'OUT_FOLDER'.
-% OUT_SUBFOLDER='avgRGB';
+OUT_SUBFOLDER='avgRGB';
 % OUT_SUBFOLDER='globalRGBhisto';
 % OUT_SUBFOLDER='spatialColour';
-OUT_SUBFOLDER='spatialColourTexture';
+% OUT_SUBFOLDER='spatialColourTexture';
 
 allfiles=dir (fullfile([DATASET_FOLDER,'/Images/*.bmp']));
 for filenum=1:length(allfiles)
@@ -37,10 +37,10 @@ for filenum=1:length(allfiles)
     fout=[OUT_FOLDER,'/',OUT_SUBFOLDER,'/',fname(1:end-4),'.mat'];%replace .bmp with .mat
     
     %% EXTRACT FUNCTION
-%     F=extractAvgRGB(img);
+    F=extractAvgRGB(img);
 %     F=extractGlobalColHist(img);
 %     F=extractSpatialColour(img);
-    F=extractSpatialColourTexture(img);
+%     F=extractSpatialColourTexture(img);
     save(fout,'F');
     toc
 end
diff --git a/cvpr_visualsearch_category_walk.m b/cvpr_visualsearch_category_walk.m
index 11d2298..14ec31f 100644
--- a/cvpr_visualsearch_category_walk.m
+++ b/cvpr_visualsearch_category_walk.m
@@ -89,10 +89,10 @@ NIMG=size(ALLFEAT,1);           % number of images in collection
 confusion_matrix = zeros(CAT_TOTAL);
 
 AP_values = zeros([1, CAT_TOTAL]);
-for run=1:CAT_TOTAL
+for iteration=1:CAT_TOTAL
     
     %% 2) Pick an image at random to be the query
-    queryimg=getRandomCategoryImage(run);    % index of a random image
+    queryimg=getRandomCategoryImage(iteration);    % index of a random image
 
     %% 3) Compute the distance of image to the query
     dst=[];
@@ -107,7 +107,7 @@ for run=1:CAT_TOTAL
         dst=[dst ; [thedst i category]];
     end
     dst=sortrows(dst,1);  % sort the results
-
+    
     %% 4) Calculate PR
     precision_values=zeros([1, NIMG]);
     recall_values=zeros([1, NIMG]);
@@ -116,8 +116,10 @@ for run=1:CAT_TOTAL
 
     query_row = dst(1,:);
     query_category = query_row(1,3);
-    fprintf('category was %s, %i, %i\n', CATEGORIES(query_category), query_category, run)
-    
+    if query_category ~= iteration
+        dst
+    end
+    fprintf('category was %s\n', CATEGORIES(query_category))
     
     %calculate PR for each n
     for i=1:NIMG
@@ -132,7 +134,7 @@ for run=1:CAT_TOTAL
                 row = rows(n, :);
                 category = row(3);
 
-                if category == query_category
+                if category == iteration
                     correct_results = correct_results + 1;
                 else
                     incorrect_results = incorrect_results + 1;
@@ -145,7 +147,7 @@ for run=1:CAT_TOTAL
         row = rows(i, :);
         category = row(3);
 
-        if category == query_category
+        if category == iteration
             correct_results = correct_results + 1;
             correct_at_n(i) = 1;
         else
@@ -153,7 +155,7 @@ for run=1:CAT_TOTAL
         end
 
         precision = correct_results / i;
-        recall = correct_results / CAT_HIST(1,query_category);
+        recall = correct_results / CAT_HIST(1,iteration);
 
         precision_values(i) = precision;
         recall_values(i) = recall;
@@ -170,9 +172,9 @@ for run=1:CAT_TOTAL
     end
 
     sum_P_rel_n = sum(P_rel_n);
-    average_precision = sum_P_rel_n / CAT_HIST(1,query_category);
+    average_precision = sum_P_rel_n / CAT_HIST(1,iteration)
     
-    AP_values(run) = average_precision;
+    AP_values(iteration) = average_precision;
     
 
 
@@ -189,7 +191,7 @@ for run=1:CAT_TOTAL
     %% These may be a little hard to see using imgshow
     %% If you have access, try using imshow(outdisplay) or imagesc(outdisplay)
     
-    SHOW=20; % Show top 15 results
+    SHOW=25; % Show top 25 results
     dst=dst(1:SHOW,:);
     outdisplay=[];
     for i=1:size(dst,1)
diff --git a/cvpr_visualsearch_pca_image.m b/cvpr_visualsearch_pca_image.m
new file mode 100644
index 0000000..c9dbda6
--- /dev/null
+++ b/cvpr_visualsearch_pca_image.m
@@ -0,0 +1,244 @@
+%% EEE3032 - Computer Vision and Pattern Recognition (ee3.cvpr)
+%%
+%% cvpr_visualsearch.m
+%% Skeleton code provided as part of the coursework assessment
+%%
+%% This code will load in all descriptors pre-computed (by the
+%% function cvpr_computedescriptors) from the images in the MSRCv2 dataset.
+%%
+%% It will pick a descriptor at random and compare all other descriptors to
+%% it - by calling cvpr_compare.  In doing so it will rank the images by
+%% similarity to the randomly picked descriptor.  Note that initially the
+%% function cvpr_compare returns a random number - you need to code it
+%% so that it returns the Euclidean distance or some other distance metric
+%% between the two descriptors it is passed.
+%%
+%% (c) John Collomosse 2010  (J.Collomosse@surrey.ac.uk)
+%% Centre for Vision Speech and Signal Processing (CVSSP)
+%% University of Surrey, United Kingdom
+
+close all;
+clear all;
+
+%% Edit the following line to the folder you unzipped the MSRCv2 dataset to
+DATASET_FOLDER = 'dataset';
+
+%% Folder that holds the results...
+DESCRIPTOR_FOLDER = 'descriptors';
+%% and within that folder, another folder to hold the descriptors
+%% we are interested in working with
+DESCRIPTOR_SUBFOLDER='avgRGB';
+% DESCRIPTOR_SUBFOLDER='globalRGBhisto';
+% DESCRIPTOR_SUBFOLDER='spatialColour';
+% DESCRIPTOR_SUBFOLDER='spatialColourTexture';
+
+CATEGORIES = ["Farm Animal" 
+    "Tree"
+    "Building"
+    "Plane"
+    "Cow"
+    "Face"
+    "Car"
+    "Bike"
+    "Sheep"
+    "Flower"
+    "Sign"
+    "Bird"
+    "Book Shelf"
+    "Bench"
+    "Cat"
+    "Dog"
+    "Road"
+    "Water Features"
+    "Human Figures"
+    "Coast"
+    ];
+
+QUERY_INDEXES=[301 358 384 436 447 476 509 537 572 5 61 80 97 127 179 181 217 266 276 333];
+
+% 1_10 2_16 3_12 4_4 5_15 6_14 7_17 8_15 9_1 10_14 11_8 12_26 13_10 14_10
+% 15_8 16_10 17_16 18_5 19_15 20_12
+
+
+%% 1) Load all the descriptors into "ALLFEAT"
+%% each row of ALLFEAT is a descriptor (is an image)
+
+ALLFEAT=[];
+ALLFILES=cell(1,0);
+ALLCATs=[];
+ctr=1;
+allfiles=dir (fullfile([DATASET_FOLDER,'/Images/*.bmp']));
+for filenum=1:length(allfiles)
+    fname=allfiles(filenum).name;
+    
+    %identify photo category for PR calculation
+    split_string = split(fname, '_');
+    ALLCATs(filenum) = str2double(split_string(1));
+    
+    imgfname_full=([DATASET_FOLDER,'/Images/',fname]);
+    img=double(imread(imgfname_full))./255;
+    thesefeat=[];
+    featfile=[DESCRIPTOR_FOLDER,'/',DESCRIPTOR_SUBFOLDER,'/',fname(1:end-4),'.mat'];%replace .bmp with .mat
+    load(featfile,'F');
+    ALLFILES{ctr}=imgfname_full;
+    ALLFEAT=[ALLFEAT ; F];
+    ctr=ctr+1;
+end
+
+% get counts for each category for PR calculation
+CAT_HIST = histogram(ALLCATs).Values;
+CAT_TOTAL = length(CAT_HIST);
+
+NIMG=size(ALLFEAT,1);           % number of images in collection
+
+confusion_matrix = zeros(CAT_TOTAL);
+
+AP_values = zeros([1, CAT_TOTAL]);
+for iteration=1:CAT_TOTAL
+    
+    %% 2) Pick an image at random to be the query
+    queryimg=QUERY_INDEXES(iteration);    % index of a random image
+    
+    %% 3) Compute EigenModel
+    E = getEigenModel(ALLFEAT);
+    E = deflateEigen(E, 2);
+    
+    %% 4) Project data to lower dimensionality
+%     ALLFEAT=ALLFEAT-repmat(E.org,size(ALLFEAT,1),1);
+    ALLFEAT=((E.vct')*(ALLFEAT'))';
+
+    %% 3) Compute the distance of image to the query
+    dst=[];
+    for i=1:NIMG
+        candidate=ALLFEAT(i,:);
+        query=ALLFEAT(queryimg,:);
+
+        category=ALLCATs(i);
+
+        %% COMPARE FUNCTION
+        thedst=compareMahalanobis(E, ALLFEAT, query);
+        dst=[dst ; [thedst i category]];
+    end
+    dst=sortrows(dst,1);  % sort the results
+
+    %% 4) Calculate PR
+    precision_values=zeros([1, NIMG]);
+    recall_values=zeros([1, NIMG]);
+
+    correct_at_n=zeros([1, NIMG]);
+
+    query_row = dst(1,:);
+    query_category = query_row(1,3);
+    if query_category ~= iteration
+        dst
+    end
+    fprintf('category was %s\n', CATEGORIES(query_category))
+    
+    
+    %calculate PR for each n
+    for i=1:NIMG
+
+        rows = dst(1:i, :);
+
+        correct_results = 0;
+        incorrect_results = 0;
+
+        if i > 1    
+            for n=1:i - 1
+                row = rows(n, :);
+                category = row(3);
+
+                if category == iteration
+                    correct_results = correct_results + 1;
+                else
+                    incorrect_results = incorrect_results + 1;
+                end
+
+            end
+        end
+
+        % LAST ROW
+        row = rows(i, :);
+        category = row(3);
+
+        if category == iteration
+            correct_results = correct_results + 1;
+            correct_at_n(i) = 1;
+        else
+            incorrect_results = incorrect_results + 1;
+        end
+
+        precision = correct_results / i;
+        recall = correct_results / CAT_HIST(1,iteration);
+
+        precision_values(i) = precision;
+        recall_values(i) = recall;
+    end
+
+
+    %% 5) calculate AP
+    P_rel_n = zeros([1, NIMG]);
+    for i = 1:NIMG
+        precision = precision_values(i);
+        i_result_relevant = correct_at_n(i);
+
+        P_rel_n(i) = precision * i_result_relevant;
+    end
+
+    sum_P_rel_n = sum(P_rel_n);
+    average_precision = sum_P_rel_n / CAT_HIST(1,iteration)
+    
+    AP_values(iteration) = average_precision;
+    
+
+
+    %% 6) plot PR curve
+    figure(1)
+    plot(recall_values, precision_values);
+    hold on;
+    title('PR Curve');
+    xlabel('Recall');
+    ylabel('Precision');
+    
+    
+    %% 7) Visualise the results
+    %% These may be a little hard to see using imgshow
+    %% If you have access, try using imshow(outdisplay) or imagesc(outdisplay)
+    
+    SHOW=25; % Show top 25 results
+    dst=dst(1:SHOW,:);
+    outdisplay=[];
+    for i=1:size(dst,1)
+       img=imread(ALLFILES{dst(i,2)});
+       img=img(1:2:end,1:2:end,:); % make image a quarter size
+       img=img(1:81,:,:); % crop image to uniform size vertically (some MSVC images are different heights)
+       outdisplay=[outdisplay img];
+       
+       %populate confusion matrix
+       confusion_matrix(query_category, dst(i,3)) = confusion_matrix(query_category, dst(i,3)) + 1;
+    end
+%     figure(3)
+%     imgshow(outdisplay);
+%     axis off;
+
+end
+
+% normalise confusion matrix
+norm_confusion_matrix = confusion_matrix ./ sum(confusion_matrix, 'all');
+
+%% 8 Calculate MAP
+% figure(4)
+% histogram(AP_values);
+% title('Average Precision Distribution');
+% ylabel('Count');
+% xlabel('Average Precision');
+% xlim([0, 1]);
+
+MAP = mean(AP_values)
+AP_sd = std(AP_values)
+
+% figure(2)
+% plot(1:CAT_TOTAL, AP_values);
+% title('Average Precision Per Run');
+% xlabel('Run');
+% ylabel('Average Precision');
diff --git a/cvpr_visualsearch_pca.m b/cvpr_visualsearch_selected_image.m
similarity index 75%
rename from cvpr_visualsearch_pca.m
rename to cvpr_visualsearch_selected_image.m
index 5857113..da7b94c 100644
--- a/cvpr_visualsearch_pca.m
+++ b/cvpr_visualsearch_selected_image.m
@@ -54,6 +54,11 @@ CATEGORIES = ["Farm Animal"
     "Coast"
     ];
 
+QUERY_INDEXES=[301 358 384 436 447 476 509 537 572 5 61 80 97 127 179 181 217 266 276 333];
+
+% 1_10 2_16 3_12 4_4 5_15 6_14 7_17 8_15 9_1 10_14 11_8 12_26 13_10 14_10
+% 15_8 16_10 17_16 18_5 19_15 20_12
+
 
 %% 1) Load all the descriptors into "ALLFEAT"
 %% each row of ALLFEAT is a descriptor (is an image)
@@ -85,55 +90,45 @@ CAT_HIST = histogram(ALLCATs).Values;
 CAT_TOTAL = length(CAT_HIST);
 
 NIMG=size(ALLFEAT,1);           % number of images in collection
-MODEL_SIZE = 10;
 
 confusion_matrix = zeros(CAT_TOTAL);
 
 AP_values = zeros([1, CAT_TOTAL]);
-for iterating_category=1:CAT_TOTAL
-    
-    %% 2) Select descriptors for category and training data
-    category_training_descriptors = [];
-    test_descriptors = [];
-    test_categories = [];
-    for i=1:NIMG
-        if (iterating_category == ALLCATs(i)) && (size(category_training_descriptors,1) < MODEL_SIZE)
-            category_training_descriptors = [ category_training_descriptors ; ALLFEAT(i,:) ];
-        else
-            test_descriptors = [ test_descriptors ; ALLFEAT(i,:) ];
-            test_categories = [ test_categories ; ALLCATs(i) ];
-        end
-    end
-    
-    [eig_vct, eig_val, model_mean] = getEigenModel(category_training_descriptors);
-    
-    TEST_SIZE = size(test_descriptors,1);
+for iteration=1:CAT_TOTAL
     
+    %% 2) Pick an image at random to be the query
+    queryimg=QUERY_INDEXES(iteration);    % index of a random image
+
     %% 3) Compute the distance of image to the query
     dst=[];
-    for i=1:TEST_SIZE
-        candidate=test_descriptors(i,:);
-        category=test_categories(i);
+    for i=1:NIMG
+        candidate=ALLFEAT(i,:);
+        query=ALLFEAT(queryimg,:);
+
+        category=ALLCATs(i);
 
         %% COMPARE FUNCTION
-        thedst=compareMahalanobis(eig_vct, eig_val, model_mean, candidate);
+        thedst=compareEuclidean(query, candidate);
         dst=[dst ; [thedst i category]];
     end
     dst=sortrows(dst,1);  % sort the results
 
     %% 4) Calculate PR
-    precision_values=zeros([1, TEST_SIZE]);
-    recall_values=zeros([1, TEST_SIZE]);
+    precision_values=zeros([1, NIMG]);
+    recall_values=zeros([1, NIMG]);
 
-    correct_at_n=zeros([1, TEST_SIZE]);
+    correct_at_n=zeros([1, NIMG]);
 
     query_row = dst(1,:);
     query_category = query_row(1,3);
-    fprintf('category was %s, %i, %i\n', CATEGORIES(query_category), query_category, iterating_category)
+    if query_category ~= iteration
+        dst
+    end
+    fprintf('category was %s\n', CATEGORIES(query_category))
     
     
     %calculate PR for each n
-    for i=1:TEST_SIZE
+    for i=1:NIMG
 
         rows = dst(1:i, :);
 
@@ -145,7 +140,7 @@ for iterating_category=1:CAT_TOTAL
                 row = rows(n, :);
                 category = row(3);
 
-                if category == query_category
+                if category == iteration
                     correct_results = correct_results + 1;
                 else
                     incorrect_results = incorrect_results + 1;
@@ -158,7 +153,7 @@ for iterating_category=1:CAT_TOTAL
         row = rows(i, :);
         category = row(3);
 
-        if category == query_category
+        if category == iteration
             correct_results = correct_results + 1;
             correct_at_n(i) = 1;
         else
@@ -166,7 +161,7 @@ for iterating_category=1:CAT_TOTAL
         end
 
         precision = correct_results / i;
-        recall = correct_results / CAT_HIST(1,query_category);
+        recall = correct_results / CAT_HIST(1,iteration);
 
         precision_values(i) = precision;
         recall_values(i) = recall;
@@ -174,8 +169,8 @@ for iterating_category=1:CAT_TOTAL
 
 
     %% 5) calculate AP
-    P_rel_n = zeros([1, TEST_SIZE]);
-    for i = 1:TEST_SIZE
+    P_rel_n = zeros([1, NIMG]);
+    for i = 1:NIMG
         precision = precision_values(i);
         i_result_relevant = correct_at_n(i);
 
@@ -183,9 +178,9 @@ for iterating_category=1:CAT_TOTAL
     end
 
     sum_P_rel_n = sum(P_rel_n);
-    average_precision = sum_P_rel_n / CAT_HIST(1,query_category);
+    average_precision = sum_P_rel_n / CAT_HIST(1,iteration);
     
-    AP_values(iterating_category) = average_precision;
+    AP_values(iteration) = average_precision;
     
 
 
@@ -202,7 +197,7 @@ for iterating_category=1:CAT_TOTAL
     %% These may be a little hard to see using imgshow
     %% If you have access, try using imshow(outdisplay) or imagesc(outdisplay)
     
-    SHOW=20; % Show top 15 results
+    SHOW=25; % Show top 25 results
     dst=dst(1:SHOW,:);
     outdisplay=[];
     for i=1:size(dst,1)
diff --git a/descriptor/extractSpatialColourTexture.m b/descriptor/extractSpatialColourTexture.m
index 01a3c5c..4f92f83 100644
--- a/descriptor/extractSpatialColourTexture.m
+++ b/descriptor/extractSpatialColourTexture.m
@@ -1,7 +1,7 @@
 function F=extractSpatialColourTexture(img)
 
-grid_rows = 4;
-grid_columns = 4;
+grid_rows = 8;
+grid_columns = 8;
 
 img_size = size(img);
 img_rows = img_size(1);
@@ -43,7 +43,7 @@ for i = 1:grid_rows
         avg_vals = extractAvgRGB(img_cell);
         [mag_img, angle_img] = getEdgeInfo(grey_img_cell);
         
-        edge_hist = getEdgeAngleHist(mag_img, angle_img, 6, 0.05);
+        edge_hist = getEdgeAngleHist(mag_img, angle_img, 8, 0.05);
         
         %concatenate average values into vector
         descriptor = [descriptor edge_hist avg_vals(1) avg_vals(2) avg_vals(3)];
diff --git a/distance/compareMahalanobis.m b/distance/compareMahalanobis.m
index 7258b95..11d1582 100644
--- a/distance/compareMahalanobis.m
+++ b/distance/compareMahalanobis.m
@@ -1,11 +1,17 @@
-function dst=compareMahalanobis(vct, val, mean, F2)
+function d=compareMahalanobis(E, obs, query)
 
-x_minus_mean = (F2 - mean)';
-matrices = val' * vct' * x_minus_mean;
+obs_translated = (obs -repmat(query, size(obs,1), 1))';
 
-x=matrices.^2;
-x=sum(x);
+proj=E.vct*obs_translated;
+    
+dstsq=proj.*proj;
 
-dst=sqrt(sqrt(x));
+E.val(E.val==0)=1; % check for eigenvalues of 0
+
+dst=dstsq./repmat((E.val),1,size(obs,2));
+
+d=sum(dst);
+
+d=sqrt(d);
 
 return;
diff --git a/report/coursework.lyx b/report/coursework.lyx
index 814d5fc..439634c 100644
--- a/report/coursework.lyx
+++ b/report/coursework.lyx
@@ -601,10 +601,16 @@ Where
  refers to the number of edge histogram bins.
 \end_layout
 
-\begin_layout Subsection
+\begin_layout Section
 Principal Component Analysis
 \end_layout
 
+\begin_layout Standard
+Principal component analysis is a process to identify the variations in
+ a set of data.
+ The result is a 
+\end_layout
+
 \begin_layout Section
 Distance Measures
 \end_layout
@@ -824,22 +830,22 @@ Category Response
 \begin_layout Standard
 The category response aims to control for a descriptor's varying performance
  at each of the dataset's categories by looping through each category and
- randomly selecting an image from each as the query image.
+ using a preselected image from each as the query image.
  Each category iteration has precision and recall values calculated for
  all 
 \begin_inset Formula $n$
 \end_inset
 
  to allow the mean average precision to be calculated.
- This mean value is calculated from 20 iterations for the MSRCv2 dataset.
+ This mean value is calculated from the 20 category iterations for the MSRCv2
+ dataset.
 \end_layout
 
 \begin_layout Standard
 Completing one iteration for each category also allows a confusion matrix
  to be constructed.
- For each iteration the top 20 results were evaluated, this number was chosen
- as this is approximately the mean number of images in each category.
- 
+ For each iteration the top 25 results were evaluated, this number was chosen
+ as this is approximately the mean category size.
 \end_layout
 
 \begin_layout Standard
@@ -847,17 +853,6 @@ The completed confusion matrix allows the main category confusions to be
  identified and discussions to be made.
 \end_layout
 
-\begin_layout Subsubsection
-Random Response
-\end_layout
-
-\begin_layout Standard
-The random response places emphasis on iteration over controlling for inter-cate
-gory response.
- Here query images are selected at random from the entire dataset and many
- iterations are run in order to identify a mean response.
-\end_layout
-
 \begin_layout Section
 Results
 \end_layout
diff --git a/util/deflateEigen.m b/util/deflateEigen.m
new file mode 100644
index 0000000..58fb518
--- /dev/null
+++ b/util/deflateEigen.m
@@ -0,0 +1,4 @@
+function E=deflateEigen(E, param)
+
+E.val=E.val(1:param);
+E.vct=E.vct(:,1:param);
diff --git a/util/getEigenModel.m b/util/getEigenModel.m
index 01500e9..d3a6919 100644
--- a/util/getEigenModel.m
+++ b/util/getEigenModel.m
@@ -1,12 +1,23 @@
-function [eig_vct, eig_val, model_mean]=getEigenModel(model_descriptors)
+function E=getEigenModel(obs)
 
-model_size = size(model_descriptors, 1);
+E.N  = size(obs,1);
+E.D  = size(obs,2);
+E.org= mean(obs);
 
-model_mean = mean(model_descriptors);
-model_data_min_mean = model_descriptors - repmat(model_mean, model_size, 1);
+obs_translated=obs-repmat(E.org,E.N,1);
 
-C = (model_data_min_mean' * model_data_min_mean) ./ model_size;
+C=(1/E.N) * (obs_translated' * obs_translated);
 
-[eig_vct, eig_val] = eig(C);
+[U V]=eig(C);
+
+% sort eigenvectors and eigenvalues by eigenvalue size (desc)
+linV=V*ones(size(V,2),1);
+S=[linV U'];
+S=flipud(sortrows(S,1));
+U=S(:,2:end)';
+V=S(:,1);
+
+E.vct=U;
+E.val=V;
 
 return;
\ No newline at end of file