Pupil Detection Research Articles

Dummy eye measurements of microsaccades: Testing the influence of system noise and head movements on microsaccade detection in a popular video-based eye tracker

Whereas early studies of microsaccades have predominantly relied on custom-built eye trackers and manual tagging of microsaccades, more recent work tends to use video-based eye tracking and automated algorithms for microsaccade detection. While data from these newer studies suggest that microsaccades can be reliably detected with video-based systems, this has not been systematically evaluated. I here present a method and data examining microsaccade detection in an often used video-based system (the Eyelink II system) and a commonly used detection algorithm (Engbert & Kliegl, 2003; Engbert & Mergenthaler, 2006). Recordings from human participants and those obtained using a pair of dummy eyes, mounted on a pair of glasses either worn by a human participant (i.e., with head motion) or a dummy head (no head motion) were compared. Three experiments were conducted. The first experiment suggests that when microsaccade measurements make use of the pupil detection mode, microsaccade detections in the absence of eye movements are sparse in the absence of head movements, but frequent with head movements (despite the use of a chin rest). A second experiment demonstrates that by using measurements that rely on a combination of corneal reflection and pupil detection, false microsaccade detections can be largely avoided as long as a binocular criterion is used. A third experiment examines whether past results may have been affected by possible incorrect detections due to small head movements. It shows that despite the many detections due to head movements, the typical modulation of microsaccade rate after stimulus onset is found only when recording from the participants’ eyes.

홍채영역에서의 홍채정보 보존율 향상을 위한 새로운 속눈썹 제거 방법

홍채 인식은 인간의 눈 영상으로부터 고유한 홍채특징을 추출하고 이를 코드화 하여 비교하는 생체인식 기술로, 이것은 시스템 안에 저장된 다른 홍채들과의 비교기술을 포함한다. 한편, 홍채 영상에서의 속눈썹은 인식률에 영향을 미치는 외부 요소인데, 만일 속눈썹이 홍채영역으로부터 정확하게 제거되지 않는다면 속눈썹을 홍채특징으로 인식하거나 홍채특징을 속눈썹으로 인식하는 오인식의 문제가 존재하게 되며, 결국 이 오인식은 홍채정보의 많은 유실을 가져오게 된다. 따라서 본 논문에서는 이러한 문제점을 해결하기 위하여 주파수 특징 분석에 사용되는 Gabor Filter를 이용한 속눈썹 제거로 홍채정보의 보존율 향상을 가져올 수 있었다. Gabor Filter는 영상의 주파수 분석을 위한 필터 중 하나인데 여기에 각도, 주파수, 가우시안 파라미터 등을 이용한 다양한 홍채영역의 특징들을 추출할 수 있는 새로운 방법으로 다양한 길이와 모양의 속눈썹을 정확하게 제거할 수 있었다. 그 결과 제안한 방법은 GMM 혹은 히스토그램 분석을 이용한 기존 방법보다 홍채영역 데이터 보존율에 있어서 약 4% 정도의 향상이 가능하였다. The iris recognition is a biometrics technology to extract and code an unique iris feature from human eye image. Also, it includes the technology to compare with other's various iris stored in the system. On the other hand, eyelashes in iris image are a external factor to affect to recognition rate of iris. If eyelashes are not removed exactly from iris area, there are two false recognitions that recognize eyelashes to iris features or iris features to eyelashes. Eventually, these false recognitions bring out a lot of loss in iris informations. In this paper, in order to solve that problems, we removed eyelashes by gabor filter that using for analysis of frequency feature and improve preservation rate of iris informations. By novel method to extract various features on iris area using angle, frequency, and gaussian parameter on gabor filter that is one of the filters for analysing frequency feature for an image, we could remove accurately eyelashes with various lengths and shapes. As the result, proposed method represents that improve about 4% than previous methods using GMM or histogram analysis in iris preservation rate.

Hybrid Projection 함수와 Rank Order 필터를 이용한 눈동자 검출

이 논문에서는 hybrid projection 함수와 rank order 필터를 이용하여 눈동자를 검출하는 방법을 제안한다. 눈썹을 눈동자로 검출하는 오류를 줄이기 위하여, hybrid projection 함수를 이용하여 얼굴 영역에서 눈썹을 검출하고 눈썹이 포함되지 않도록 눈 영역을 설정한다. 눈 영역에서 rank order 필터를 사용하여 눈동자 후보점을 찾고 위치를 보정한다. 두 눈동자 후보점을 기하학적인 제약조건을 기반으로 쌍으로 묶고 각 쌍의 두 눈에 대한 유사도를 정합을 이용하여 측정하여가장작은값을 갖는 쌍을 최종눈동자로 결정한다. BioID 얼굴데이터베이스의 얼굴 영상 700개에 대한 실험 결과 92.4%의 검출율을 얻었으며 기존 방법보다 약 21.5% 개선된 결과를 얻었다. In this paper, we propose a pupil detection method using hybrid projection function and rank order filter. To reduce error to detect eyebrows as pupil, eyebrows are detected using hybrid projection function in face region and eye region is set to not include the eyebrows. In the eye region, potential pupil candidates are detected using rank order filter and then the positions of pupil candidates are corrected. The pupil candidates are grouped into pairs based on geometric constraints. A similarity measure is obtained for two eye of each pair using template matching, we select a pair with the smallest similarity measure as final two pupils. The experiments have been performed for 700 images of the BioID face database. The pupil detection rate is 92.4% and the proposed method improves about 21.5% over the existing method..

A statistical-based decision for arabic pronunciation assessment

The aim of a computer assisted language learning (CALL) system is to improve the language skills of learners. Such systems often include, grammar and vocabulary components, while the pronunciation learning seems to be the hardest step in language learning process. Little attention has been paid to this aspect among the required ones in CALL systems. In pronunciation learning context, the learner would like to know if its pronunciation is good or bad. In the case where the pronunciation is bad, it will be suitable if some advices are given to him. The goal of this work is an early detection of pupils with reading difficulties and in the issue of decision whether their pronunciation is good or not is our particular interest. For this purpose, we consider the answer to this question as a classification problem and we use a statistical approach to make a decision; this approach allows us to pursue the investigation concerning the pronunciation of every phoneme in the word or in the sentence.

Iris Biometric Authentication used for Security Systems

Pupil detection and iris localisation using scanning method and feature extraction is performed with five level decomposition techniques, with these two proposed algorithm we could achieve efficient and fast person authentication in biometric security systems. Statistical performance evaluation is also performed using parameters False acceptance rate (FAR), False rejection rate (FRR), Correct recognition rate (CRR), Equal error rate (EER), Match ratio etc, using CASIA database.

眼鏡着用時における環境条件にロバストな瞳孔検出(視聴覚技術,ヒューマンインタフェースおよび一般)

眼鏡着用時における環境条件にロバストな瞳孔検出(視聴覚技術,ヒューマンインタフェースおよび一般)

ACCURATE AND FAST PUPIL LOCALIZATION USING CONTRAST STRETCHING, SEED FILLING AND CIRCULAR GEOMETRICAL CONSTRAINTS

Iris segmentation is the most contested issue in th e iris recognition system, since noise and poor ima ge quality can significantly affect accuracy of iris l ocalization stage. Therefore, very careful attentio n has to be paid for the segmentation process if only an accura te result is expected. This study presents a new me thod for precise pupil detection capable of handling the unconstrained bad acquisition conditions especiall y those related to low contrast or to the non-uniform brigh tness caused by the position of light sources, spec ular reflection, eyelashes and eyelids. Contrast stretch ing (normalization) technique is used for handling the variations in contrast and illumination in an iris image by stretching’ the range of intensity values. Next, the local integration is applied on the enhanced image, this process will enhance the contrast level betwe en the existing white and black areas of the image; this w ill useful to compute the optimal threshold value r equired to perform a successful image binarization for the purpose of isolation of the pupil region, the seed fill algorithm is used as region growing method to segment the binary image and allocate the pupil as a cir cular black segment with biggest area, the approximate pu pil center is detected then for removing the specul ar reflection, the pupil is filled with black color us ing a simple filling method. Finally a circle fitti ng algorithm is used for precisely allocating the circular pupil region by the fact that richer iris textures are n ot closer to the pupil boundary. A set of tests was conducted on 2,655 iris images which were downloaded from CASIA V3.0-interval standard dataset; the test results in dicated that the proposed method had subjectively 1 00% accuracy rate with pupil localization, process sati sfy the real time constraints even when dealing wit h images have very different brightness or contrast c onditions or they contain eyelashes artifacts.

3カメラによる眼鏡着用者における瞳孔検出改善

3カメラによる眼鏡着用者における瞳孔検出改善

Feature Extraction and Pupil Detection Algorithm Used for Iris Biometric Authentication System

Iris biometric is most mature and secure authentication system as compared to other systems. Other authentication system does exist apart from biometrics such as PIN, password etc., which are not secure and more vulnerable to attacks and can be hacked or spoofed easily. Using, Iris biometric we can enhance overall performance in terms of accuracy, which is possible if and only if the pupil part must be removed perfectly and efficiently. Pupil part is unwanted part for our system. Pupil part is surrounded by iris part when extracted successfully we get two approximate concentric circle. Proposed scanning algorithm successfully extracts pupil part and defines iris part with less complexity and more efficiently. Iris part is consisting of patterns which are desired for authenticating a person and each patterns are represented in terms of feature vectors and stored in database. Proposed system focuses on feature extraction using five level decomposition technique implemented with haar, db2 and db4 and achieves high accuracy with reduced error rates. Due to reduced errors and considering lower half of iris part, proposed algorithm can be used for larger database such as for Aadhar because it takes less time for feature extraction and has less complexity with reduced mathematical burden on the system and improves good accuracy.

Separability Filter for Localizing Abnormal Pupil: Identification of Input Image

S eparability filter method is a reliable method for pupil detection . However, so far this method is implemented for detecting pupil of normal eye, while for abnormal eye such as cataract and glaucoma patients; they have different characteristics of pupil such as color, shape and radius size of pupil. In this paper we propose to use separability filter for detecting pupil of abnormal patients with different characteristics. We faced a problem about radius size, shape and color of pupil; therefore we implemented Hough Transform, Blob area and Brightness for identifying input images before applying separability filter. The experiment results show that we can increase performance of pupil detection for abnormal eye to be 95.65%.

Rank Order Filter와 상호상관을 이용한 강인한 눈동자 검출

In this paper, we propose a robust pupil detection method using rank order filter and cross-correlation. Potential pupil candidates are detected using rank order filter. Eye region is binarized using variable threshold to find eyebrow, and pupil candidates at the eyebrow are removed. The positions of pupil candidates are corrected, the pupil candidates are grouped into pairs based on geometric constraints. A similarity measure is obtained for two eye of each pair using cross-correlation, we select a pair with the largest similarity measure as a final pupil. The experiments have been performed for 500 images of the BioID face database. The results show that it achieves the high detection rate of 96.8% and improves about 11.6% than existing method.

Eyelid contour detection and tracking for startle research related eye-blink measurements from high-speed video records

Using the positions of the eyelids is an effective and contact-free way for the measurement of startle induced eye-blinks, which plays an important role in human psychophysiological research. To the best of our knowledge, no methods for an efficient detection and tracking of the exact eyelid contours in image sequences captured at high-speed exist that are conveniently usable by psychophysiological researchers.In this publication a semi-automatic model-based eyelid contour detection and tracking algorithm for the analysis of high-speed video recordings from an eye tracker is presented. As a large number of images have been acquired prior to method development it was important that our technique is able to deal with images that are recorded without any special parametrisation of the eye tracker. The method entails pupil detection, specular reflection removal and makes use of dynamic model adaption.In a proof-of-concept study we could achieve a correct detection rate of 90.6%. With this approach, we provide a feasible method to accurately assess eye-blinks from high-speed video recordings.

Iris Texture Analysis for Security Systems

Biometric security is highly reliable and secure system. Proposed work, efficient methods for pupil detection and wavelet transformation with five-level decomposition for feature extraction are proposed and which results with accurate feature vector are stored as bits and then processes for identification and verification. Statistical performance evaluation using parameters and classifier used hamming distance for matching the patterns efficiently with stored database .We use CASIA database.

Robust Eye and Pupil Detection Method for Gaze Tracking

Robust and accurate pupil detection is a prerequisite for gaze detection. Hence, we propose a new eye/pupil detection method for gaze detection on a large display. The novelty of our research can be summarized by the following four points. First, in order to overcome the performance limitations of conventional methods of eye detection, such as adaptive boosting (Adaboost) and continuously adaptive mean shift (CAMShift) algorithms, we propose adaptive selection of the Adaboost and CAMShift methods. Second, this adaptive selection is based on two parameters: pixel differences in successive images and matching values determined by CAMShift. Third, a support vector machine (SVM)-based classifier is used with these two parameters as the input, which improves the eye detection performance. Fourth, the center of the pupil within the detected eye region is accurately located by means of circular edge detection, binarization and calculation of the geometric center. The experimental results show that the proposed method can detect the center of the pupil at a speed of approximately 19.4 frames/s with an RMS error of approximately 5.75 pixels, which is superior to the performance of conventional detection methods.

Comparison of Different Algorithms for Robust Detection of Pupils in Real-Time Eye-Tracking Experiments

Comparison of Different Algorithms for Robust Detection of Pupils in Real-Time Eye-Tracking Experiments

A video-based eye pupil detection system for diagnosing bipolar disorder

Eye pupil detection systems have become increasingly popular in image processing and computer vision applications in medical systems. In this study, a video-based eye pupil detection system is developed for diagnosing bipolar disorder. Bipolar disorder is a condition in which people experience changes in cognitive processes and abilities, including reduced attentional and executive capabilities and impaired memory. In order to detect these abnormal behaviors, a number of neuropsychological tests are also designed to measure attentional and executive abilities. The system acquires the position and radius information of eye pupils in video sequences using an active contour snake model with an ellipse-fitting algorithm. The system also determines the time duration of the eye pupils looking at certain regions and the duration of making decisions during the neuropsychological tests. The tests are applied to 2 different groups consisting of people with bipolar disorder (bipolar group) and people without bipolar disorder (control group) in order to mathematically model the people with bipolar disorder. The mathematical modeling is performed by using the support vector machines method. It is a supervised learning method that analyzes data and recognizes patterns for classification. The developed system acquires data from the being tested and it classifies the person as bipolar or nonbipolar based on the learned mathematical model.

A Fast Pupil Detection Using Geometric Properties of Circular Objects

They are well-known geometric properties of a circle that the perpendicular bisector of a chord passes through the center of a circle, and the intersection of the perpendicular bisectors of any two chords is its center. This paper is related to a fast pupil detection method capable of detecting the center and the radius of a pupil using these geometric properties at high speed when detecting the pupil region for iris segmentation. The proposed method is characterized as rapidly detecting the center and the radius of the pupil, extracting the candidate points of the circle in human eye images using morphological operations, and finding two chords using four points on the circular edge, and taking the intersection of the perpendicular bisectors of these two chords for its center. The proposed method can not only detect the center and the radius of a pupil rapidly but also find partially occluded pupils in human eye images.

EDCircles: A real-time circle detector with a false detection control

We propose a real-time, parameter-free circle detection algorithm that has high detection rates, produces accurate results and controls the number of false circle detections. The algorithm makes use of the contiguous (connected) set of edge segments produced by our parameter-free edge segment detector, the Edge Drawing Parameter Free (EDPF) algorithm; hence the name EDCircles. The proposed algorithm first computes the edge segments in a given image using EDPF, which are then converted into line segments. The detected line segments are converted into circular arcs, which are joined together using two heuristic algorithms to detect candidate circles and near-circular ellipses. The candidates are finally validated by an a contrario validation step due to the Helmholtz principle, which eliminates false detections leaving only valid circles and near-circular ellipses. We show through experimentation that EDCircles works real-time (10–20ms for 640×480 images), has high detection rates, produces accurate results, and is very suitable for the next generation real-time vision applications including automatic inspection of manufactured products, eye pupil detection, circular traffic sign detection, etc.

Effective Driver Fatigue Monitoring through Pupil Detection and Yawing Analysis in Low Light Level Environments

Effective Driver Fatigue Monitoring through Pupil Detection and Yawing Analysis in Low Light Level Environments

Rank Order Filter와 화소값 차이를 이용한 강인한 눈동자 검출

In this paper, we propose a robust pupil detection method using rank order filter and pixel value difference in facial image. We have detected the potential pupil candidates using rank order filter. Many false pupil candidates found at eyebrow are removed using the fact that the pixel difference is much at the boundary between pupil and sclera. The rest pupil candidates are grouped into pairs. Each pair is verified according to geometric constraints such as the angle and the distance between two candidates. A fitness function is obtained for each pair using the pixel values of two pupil regions, we select a pair with the smallest fitness value as a final pupil. The experiments have been performed for 400 images of the BioID face database. The results show that it achieves more than 90% accuracy, and especially the proposed method improves the detection rate and high accuracy for face with spectacle.