Camera tracking and the construction of a robust and accurate map in unknown environments are still challenging tasks in computer vision and robotic applications. Visual Simultaneous Localization and Mapping (SLAM) along with Augmented Reality (AR) are two important applications, and their performance is entirely dependent on the accuracy of the camera tracking routine. This paper presents a novel feature-based approach for the monocular SLAM problem using a hand-held camera in room-sized workspaces with a maximum scene depth of 4–5 m. In the core of the proposed method, there is a Particle Filter (PF) responsible for the estimation of extrinsic parameters of the camera. In addition, contrary to key-frame based methods, the proposed system tracks the camera frame by frame and constructs a robust and accurate map incrementally. Moreover, the proposed algorithm initially constructs a metric sparse map. To this end, a chessboard pattern with a known cell size has been placed in front of the camera for a few frames. This enables the algorithm to accurately compute the pose of the camera and therefore, the depth of the primary detected natural feature points are easily calculated. Afterwards, camera pose estimation for each new incoming frame is carried out in a framework that is merely working with a set of visible natural landmarks. Moreover, to recover the depth of the newly detected landmarks, a delayed approach based on linear triangulation is used. The proposed method is applied to a realworld VGA quality video (640 × 480 pixels) where the translation error of the camera pose is less than 2 cm on average and the orientation error is less than 3 degrees, which indicates the effectiveness and accuracy of the developed algorithm.

Camera tracking is an important issue in many computer vision and robotics applications, such as, augmented re ality and Simultaneous Localization And Mapping (SLAM). In this paper, a feature-based technique for monocular camera tracking is proposed. The proposed approach is based on tracking a set of sparse features, which are successively tracked in a stream of video frames. In the developed system , camera initially views a chessboard with known cell size for few frames to be e nable d to construct initial map of the environment. The re after, Camera pose estimation for each new incoming frame is carried out in a framework that is merely working with a se t of visible natural landmarks. Estimation of 6-DO F camera pose parameters is performed using a particle filter. Moreover, re cove ring depth of newly detected landmarks, a linear triangulation method is used. The proposed method is applied on re al world videos and positioning error of the camera pose is less than 3 cm in average that indicates effectiveness and accuracy of the proposed method.

Background and Objectives The aim of this study was to Acute changes in aldolase activity and some hematologic parameters compared to different recoveries. Subjects and Methods The research is of applied type and quasi-experimental research method which was conducted in field-laboratory form with pre-test-post-test design with control group on female semiprofessional athletes in athletics (runners) in Tehran. Sampling was done by simple random sampling, so that after informing and inviting interested people and passing the preliminary stages, 30 runners were selected as the research sample and randomly in 3 groups of 10 people (active recycling group (running), inactivated recycling group (sports massage) and inactive sitting). The main activity included a sports competition. Blood samples were taken from the samples in 3 stages (pre-test (fasting), post-race and post-recovery). In this study, one-way analysis of variance and SPSS statistical software v. 22 were used to examine the data at a significance level of P<0.05. Results The results of this study showed that there is no significant difference between the three types of recycling methods in changing the amount of aldolase and erythrocyte factors (P>0.05), but recycling by massage has an effect on reducing aldolase levels after strenuous exercise. There is a significant difference between the three types of recycling methods (passive, jogging, massage) in reducing the number of white blood cells and hemoglobin in favor of recovery by the massage group. Conclusion According to the results, it can be said that among the recovery methods, the use of massage was more effective in reducing the aldolase activity of female athletes after the run competition.

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