Real-time robust vision-based hand gesture recognition using stereo images

This paper presents a real-time and robust approach to recognize two types of gestures consisting of seven motional gestures and six finger spelling gestures. This approach utilizes stereo images captured by a stereo webcam to achieve robust recognition under realistic lighting conditions and in various backgrounds. It incorporates several existing computationally efficient techniques and introduces a rule-based approach to merge the information from a pair of stereo images leading to an improved hand detection compared to using single images. The results obtained indicate that high recognition rates under realistic conditions are obtained in real-time on PC platforms at the rate of 30 frames per second. It is shown that its outcome is comparable to two existing approaches while it is computationally more efficient than these approaches.     

Automatic Right Ventricular Ejection Fraction Computation from Equilibrium and First-Pass Scintigraphic Cardiac Images

Nakamura, E., Kehtarnavaz, N., Wendt, R. III, and Murphy, P., Automatic Right Ventricular Ejection Fraction Computation from Equilibrium and First-Pass Scintigraphic Cardiac Images,Digital Signal Processing6(1996), 233–239.This paper presents an automatic method for computing the right ventricular ejection fraction (RVEF) by using both equilibrium and first-pass scintigraphic cardiac images. The equilibrium images are used to extract the cardiac activity area. Together with the phase image derived from the right heart first-pass images, the cardiac area is then used to identify the subarea corresponding to the right ventricle. The RVEF is then computed from the regional counts in the end-diastolic and end-systolic frames. The average manually derived RVEFs agreed with the automatically determined RVEFs with anRvalue of 0.81. Using the average of the manually derived RVEFs as the “gold standard,” only one person processing manually had a lower mean squared error than the automatic program. These results suggest that automatic RVEF computation is potentially useful and hence clinical deployment is recommended.     

Skin lesion classification using oblique-incidence diffuse reflectance spectroscopic imaging

We discuss the use of a noninvasive in vivo optical technique, diffuse reflectance spectroscopic imaging with oblique incidence, to distinguish between benign and cancer-prone skin lesions. Various image features were examined to classify the images from lesions into benign and cancerous categories. Two groups of lesions were processed separately: Group 1 includes keratoses, warts versus carcinomas; and group 2 includes common nevi versus dysplastic nevi. A region search algorithm was developed to extract both one- and two-dimensional spectral information. A bootstrap-based Bayes classifier was used for classification. A computer-assisted tool was then devised to act as an electronic second opinion to the dermatologist. Our approach generated only one false-positive misclassification out of 23 cases collected for group 1 and two misclassifications out of 34 cases collected for group 2 under the worst estimation condition.     

A fast feature-assisted adaptive early termination approach for multiple reference frames motion estimation in H.264

The multiple reference frames motion estimation approach used in H.264 is computationally intensive. This paper presents a fast or computationally efficient feature-assisted adaptive early termination approach in order to reduce the computational complexity while maintaining more or less the same video quality. The introduced feature-assisted approach consists of three parts: (1) reduction of the number of available reference frames using predicted motion activity, extracted texture information, and skip mode from neighboring macroblocks, (2) the most probable reference frame prediction based on neighboring macroblocks, and (3) an adaptive early termination threshold derived from a theoretical analysis of all zero block detection. Extensive experimental results are performed to demonstrate the computational gain of the introduced approach over the standard approach for the multiple reference frames motion estimation.     

Fast adaptive termination mode selection for H.264 scalable video coding

Although scalable video coding can achieve coding efficiencies comparable with single layer video coding, its computational complexity is higher due to its additional inter-layer prediction process. This paper presents a fast adaptive termination algorithm for mode selection to increase its computation speed while attempting to maintain its coding efficiency. The developed algorithm consists of the following three main steps which are applied not only to the enhancement layer but also to the base layer: a prediction step based on neighboring macroblocks, a first round check step, and a second round check step or refinement if failure occurs during the first round check. Comparison results with the existing algorithms are provided. The results obtained on various video sequences show that the introduced algorithm achieves about one-third reduction in the computation speed while generating more or less the same video quality.

Computationally efficient image deblurring using low rank image approximation and its GPU implementation

This paper presents a computationally efficient technique for reduction of blur caused by handshakes in images captured by mobile devices. This technique uses a short-exposure or a low-exposure image that is captured at the same time a normal or auto-exposure image is captured. The short-exposure image is enhanced by utilizing low rank image approximation of the auto-exposure image without requiring any user specified parameters. Based on the three quantitative measures of image quality, it is shown that this technique outperforms similar techniques used for image deblurring while it also offers computational efficiency. A GPU implementation of this technique is also reported.