Stephen Rawls

Pose-Aware Face Recognition in the Wild

We propose a method to push the frontiers of unconstrained face recognition in the wild, focusing on the problem of extreme pose variations. As opposed to current techniques which either expect a single model to learn pose invariance through massive amounts of training data, or which normalize images to a single frontal pose, our method explicitly tackles pose variation by using multiple pose specific models and rendered face images. We leverage deep Convolutional Neural Networks (CNNs) to learn discriminative representations we call Pose-Aware Models (PAMs) using 500K images from the CASIA WebFace dataset. We present a comparative evaluation on the new IARPA Janus Benchmark A (IJB-A) and PIPA datasets. On these datasets PAMs achieve remarkably better performance than commercial products and surprisingly also outperform methods that are specifically fine-tuned on the target dataset.

Face recognition using deep multi-pose representations

We introduce our method and system for face recognition using multiple pose-aware deep learning models. In our representation, a face image is processed by several pose-specific deep convolutional neural network (CNN) models to generate multiple pose-specific features. 3D rendering is used to generate multiple face poses from the input image. Sensitivity of the recognition system to pose variations is reduced since we use an ensemble of pose-specific CNN features. The paper presents extensive experimental results on the effect of landmark detection, CNN layer selection and pose model selection on the performance of the recognition pipeline. Our novel representation achieves better results than the state-of-the-art on IARPAs CS2 and NISTs IJB-A in both verification and identification (i.e. search) tasks.

Learning document image binarization from data

We present a fully trainable solution for binarization of degraded document images using extremely randomized trees. Unlike previous attempts that often use simple features, our method encodes all heuristics about whether or not a pixel is foreground text into a high-dimensional feature vector and learns a more complicated decision function. We introduce two novel features, the Logarithm Intensity Percentile (LIP) and the Relative Darkness Index (RDI), and combine them with low level features, and reformulated features from existing binarization methods. Experimental results show that using small sample size (about 1.5% of all available training data), we can achieve a binarization performance comparable to manually-tuned, state-of-the-art methods. Additionally, the trained document binarization classifier shows good generalization capabilities on out-of-domain data.

EPAT: Euclidean Perturbation Analysis and Transform - An Agnostic Data Adaptation Framework for Improving Facial Landmark Detectors

We propose EPAT, (Euclidean Perturbation Analysis and Transform) a novel unsupervised adaptation approach for improving the accuracy of any facial landmark detector by characterizing the stability of landmark prediction on test images. In EPAT, a test image is transformed several times using a set of Euclidean transforms, producing several perturbed images. The black box landmark detector is used to find facial landmarks on each perturbed version of the test image. Subsequently, inverse transforms are applied to the corresponding landmarks in order to map them back to the original image. Mean and variance are calculated for all inversely transformed detection. Mean and variance represent the new ensemble prediction and the sensitivity of the underlying landmark detector, respectively. We also introduce affine variance (AV) of facial landmarks. AV is used as a measure of the stability of the predicted landmarks and a criterion for selecting a good data adaptation model which effectively addresses potential mismatches between test and training data of the underlying landmark detector. EPAT is evaluated using four state-of-theart landmark detectors on the standard 300W dataset and also incorporated into a face recognition pipeline to show improved recognition accuracy on the challenging IJB-A dataset.

Combining deep learning and language modeling for segmentation-free OCR from raw pixels

We present a simple yet effective LSTM-based approach for recognizing machine-print text from raw pixels. We use a fully-connected feed-forward neural network for feature extraction over a sliding window, the output of which is directly fed into a stacked bi-directional LSTM. We train the network using the CTC objective function and use a WFST language model during recognition. Experimental results show that this simple system outperforms extensively tuned state-of-the-art HMM models on the DARPA Arabic Machine Print corpus.

Computationally efficient template-based face recognition

Classically, face recognition depends on computing the similarity (or distance) between a pair of face images and/or their respective representations, where each subject is represented by one image. Template-based face recognition was introduced by the release of IARPAs Janus Benchmark-A (IJB-A) dataset, in which each enrolled subject is represented by a group of one or more images, called a template. The group of images comprising a template might have been acquired using different head poses, illuminations, ages and facial expressions. Template images could come from still images or video frames. Therefore, measuring the similarity between templates representing two subjects significantly increases the number of pairwise image comparisons (i.e., O(NM), where N and M are the number of image templates being compared). As the number of enrolled subjects, K, increases, both computational and space requirements become computationally prohibitive. To address this challenge, we present a novel approximate nearest-neighbor (ANN) search-based solution. Given a query template, ANN methods are used to find similar face images. Retrieved images are used to construct a template pool that is used to find the correct identity of the query subject. The proposed approach largely reduces the number of imposter template-pair comparisons. Experimental results on the IJB-A dataset show that the proposed approach achieves significant speed-up and storage savings, without sacrificing accuracy.