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| author | nunzip <np.scarh@gmail.com> | 2018-12-13 15:41:05 +0000 | 
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| committer | nunzip <np.scarh@gmail.com> | 2018-12-13 15:41:05 +0000 | 
| commit | 99deea0b69ccd1d7ad8ef889e6da052beda37fef (patch) | |
| tree | a351048911e5a18b8a0ca4b2457f13d78199b90b /report | |
| parent | 593e701b22513809816359f14a5045528cc50bef (diff) | |
| download | vz215_np1915-99deea0b69ccd1d7ad8ef889e6da052beda37fef.tar.gz vz215_np1915-99deea0b69ccd1d7ad8ef889e6da052beda37fef.tar.bz2 vz215_np1915-99deea0b69ccd1d7ad8ef889e6da052beda37fef.zip  | |
Minor layout adjustments
Diffstat (limited to 'report')
| -rwxr-xr-x | report/paper.md | 22 | 
1 files changed, 11 insertions, 11 deletions
diff --git a/report/paper.md b/report/paper.md index 79d4183..79612c3 100755 --- a/report/paper.md +++ b/report/paper.md @@ -16,7 +16,7 @@ The dataset CUHK03 contains 14096 pictures of people captured from two  different cameras. The feature vectors used, extracted from a trained ResNet50 model  , contain 2048 features that are used for identification. -The pictures represent 1467 different identities, each of which appears 9 to 10 +The pictures represent 1467 different identities, each of which appears 7 to 10  times. Data is seperated in train, query and gallery sets with `train_idx`,   `query_idx` and `gallery_idx` respectively, where the training set has been used   to develop the ResNet50 model used for feature extraction. This procedure has  @@ -41,9 +41,6 @@ distance:  $$ \textrm{NN}(x) = \operatorname*{argmin}_{i\in[m]} \|x-x_i\| $$ -Alternative distance metrics exist such as jaccardian and mahalanobis, which can -be used as an alternative to euclidiean distance. -  # Baseline Evaluation  To evaluate improvements brought by alternative distance learning metrics a baseline  @@ -105,21 +102,22 @@ We find that for the query and gallery set clustering does not seem to improve i  \end{center}  \end{figure} -# Suggested Improvement -  ## Mahalanobis Distance  We were not able to achieve significant improvements using mahalanobis for   original distance ranking compared to square euclidiaen metrics.  -The mahalanobis distance metric was used to create the ranklist as an alternative to euclidean distance. -When performing mahalanobis with the training set as the covariance matrix, reported accuracy is reduced to **38%** . +The mahalanobis distance metric was used to create the ranklist as an alternative to euclidean distance: + +$$ d_M(p,g_i) = (p-g_i)^TM(p-g_i). $$ + +When performing mahalanobis with the covariance matrix $M$ generated from the training set, reported accuracy is reduced to **38%** .  We also attempted to perform the same mahalanobis metric on a reduced PCA featureset. This allowed for significant execution   time improvements due to the greatly reduced computation requierments for smaller featurespace, but nevertheless demonstrated no  improvements over an euclidean metric. -These results are likely due to the **extremely** low covariance of features in the training set. This is evident when looking at the Covariance matrix of the training data, and is also visible in figure \ref{fig:subspace}. This is likely the result of the feature transformations performed the the ResNet-50 convolution model the features were extracted from. +These results are likely due to the **extremely** low covariance of features in the training set. This is evident when looking at the covariance matrix of the training data, and is also visible in figure \ref{fig:subspace}. This is likely the result of the feature transformations performed the the ResNet-50 convolution model the features were extracted from.  \begin{figure}  \begin{center} @@ -130,6 +128,8 @@ These results are likely due to the **extremely** low covariance of features in  \end{center}  \end{figure} +# Suggested Improvement +  ## $k$-reciprocal Re-ranking Formulation  The approach addressed to improve the identification performance is based on @@ -167,11 +167,11 @@ e\textsuperscript{\textit{-d(p,g\textsubscript{i})}}, & \text{if}\ \textit{g\tex  Through this transformation it is possible to reformulate the distance obtained   through Jaccardian metric as:  -$$ d_J(p,g_i)=1-\frac{\sum\limits_{j=1}^N min(V_{p,g_j},V_{g_i,g_j})}{\sum\limits_{j=1}^N max(V_{p,g_j},V_{g_i,g_j})} $$ +$$ d_J(p,g_i)=1-\frac{\sum\limits_{j=1}^N min(V_{p,g_j},V_{g_i,g_j})}{\sum\limits_{j=1}^N max(V_{p,g_j},V_{g_i,g_j})}. $$  It is then possible to perform a local query expansion using the g\textsubscript{i} neighbors of  defined as: -$$ V_p=\frac{1}{|N(p,k_2)|}\sum\limits_{g_i\in N(p,k_2)}V_{g_i} $$.  +$$ V_p=\frac{1}{|N(p,k_2)|}\sum\limits_{g_i\in N(p,k_2)}V_{g_i}. $$   We refer to $k_2$ since we limit the size of the nighbors to prevent noise   from the $k_2$ neighbors. The dimension k of the *$R^*$* set will instead   be defined as $k_1$: $R^*(g_i,k_1)$.  | 
