REAL-TIME ADAPTIVE COLOR SNAKE TRACKER USING CONDENSATION ALGORITHM

Abstract: Motion tracking and object segmentation are the most fundamental and critical problems in vision tasks such as motion analysis. An active contour model, snake, was developed as a useful segmenting and tracking tool for rigid or non-rigid objects. Snake is designed on the basis of snake energies. Segmenting and tracking can be executed successfully by energy minimization. In this research, two new paradigms for segmentation and tracking are suggested. First, because the conventional method uses only intensity information, it is difficult to separate an object from its complex background. Therefore, a new energy and design schemes should be proposed for the better segmentation of objects. Second, conventional snake can be applied in situations where the change between images is small. If a fast moving object exists in successive images, conventional snake will not operate well because the moving object may have large differences in its position or shape, between successive images. Snake's nodes may also fall into the local minima in their motion to the new positions of the target object in the succeeding image. For robust tracking, the condensation algorithm was adopted to control the parameters of the proposed snake model called "adaptive color snake model". The effectiveness of the ACSM is verified by appropriate simulations and experiments

Self-tuning Control for Articulated Robots Using the Plestan's Method

A self-tuning controller is proposed for an articulated robot using the Plestan’s method. To this end, we reconstruct the articulated robot dynamics exploiting the time-delay estimation (TDE) technique. The closed-loop error dynamics is described with sliding variables and TDE error; then, the Plestan’s sliding mode based gain-adaptation law is incorporated with the TDE technique. The stability of the overall dynamics is proven in the sense of Lyapunov. As a result, self-tuning of the gain is realized through the sliding variable. When the TDE error increases due to the nonlinear effect such as friction, the adaptive gain is automatically adjusted to counteract the TDE error. Chattering can be avoided because the sliding mode based gain dynamics does not allow the gain increase to an excessively high value. The superiority of the proposed self-tuning controller is demonstrated by comparative experiments on a multiple joints robot setup

Real-Time Object Tracking and Segmentation Using Adaptive Color Snake Model

Abstract: Motion tracking and object segmentation are the most fundamental and critical problems in vision tasks such as motion analysis. An active contour model, snake, was developed as a useful segmenting and tracking tool for rigid or non-rigid objects. In this paper, the development of new snake model called “adaptive color snake model (ACSM) ” for segmentation and tracking is introduced. The simple operation makes the algorithm runs in real-time. For robust tracking, the condensation algorithm was adopted to control the parameters of ACSM. The effectiveness of the ACSM is verified by appropriate simulations and experiments

Robot Plan Model Generation and Execution with Natural Language Interface

Verbal interaction between a human and a robot may play a key role in conveying suitable directions for a robot to achieve the goal of a user's request. However, a robot may need to correct task plans or make new decisions with human help, which would make the interaction inconvenient and also increase the interaction time. In this paper, we propose a new verbal interaction-based method that can generate plan models and execute proper actions without human involvement in the middle of performing a task by a robot. To understand the verbal behaviors of humans when giving instructions to a robot, we first conducted a brief user study and found that a human user does not explicitly express the required task. To handle such unclear instructions by a human, we propose two different algorithms that can generate a component of new plan models based on intents and entities parsed from natural language and can resolve the unclear entities existed in human instructions. An experimental scenario with a robot, Cozmo, was tried in the lab environment to test whether or not the proposed method could generate an appropriate plan model. As a result, we found that the robot could successfully accomplish the task following human instructions and also found that the number of interactions and components in the plan model could be reduced as opposed to the general reactive plan model. In the future, we are going to improve the automated process of generating plan models and apply various scenarios under different service environments and robots

An Effective Adaptive Gain Dynamics for Time-Delay Control of Robot Manipulators

The time-delay control (TDC) has recently been spotlighted as an effective solution owing to model-free, efficient, and robust properties thanks to a time-delay estimation (TDE) technique. The gain of TDC, usually denoted by MN, is crucial for its stability and performance, and it is reported that the constant gain of TDC does not always guarantee the best performance. To cope with this problem, this paper proposes an effective gain adaptation together with a nonlinear desired error dynamics and a new sliding variable. The resulting adaptive gain dynamics is combined with the TDC to form the proposed control, whose closed-loop stability is proved. Through simulation and experiment, we have shown that the proposed control enables to transfer MN from an unstable initial value to a stable one, better than a best-tuned gain by trial and error. As a result, the proposed control is model-free, able to achieve time responses as fast as the inclusive enhanced TDC (IETDC) - arguably the fastest TDC - and tracking accuracy better than the IETDC. The proposed method has shown a strong potential to significantly relieve the burden of gain selection.1

Marker-Based Method for Recognition of Camera Position for Mobile Robots

Position recognition is one of the core technologies for driving a robot because of differences in environment and rapidly changing situations. This study proposes a strategy for estimating the position of a camera mounted on a mobile robot. The proposed strategy comprises three methods. The first is to directly acquire information (e.g., identification (ID), marker size and marker type) to recognize the position of the camera relative to the marker. The advantage of this marker system is that a combination of markers of different sizes or having different information may be used without having to update the internal parameters of the robot system even if the user frequently changes or adds to the marker’s identification information. In the second, two novel markers are proposed to consider the real environment in which real robots are applied: a nested marker and a hierarchical marker. These markers are proposed to improve the ability of the camera to recognize markers while the camera is moving on the mobile robot. The nested marker is effective for robots like drones, which land and take off vertically with respect to the ground. The hierarchical marker is suitable for robots that move horizontally with respect to the ground such as wheeled mobile robots. The third method is the calculation of the position of an added or moved marker based on a reference marker. This method automatically updates the positions of markers after considering the change in the driving area of the mobile robot. Finally, the proposed methods were validated through experiments

A Study on Cu(In,Ga)Se2 thin-film characteristics during three-stage process using real-time substrate monitoring

In this study, to analyze the effect of the second stage (Cu-Se) deposition time on CIGS property, the experiment of controlling the time of the second stage was conducted. Especially, very low values were found for device properties when it was 3300s and 3500s in the second stage. It was observed that excess Cu2-xSe diffused excessively on the surface of the thin film, causing a lot of pores and voids on the surface.With the same evaporation ratio for each source of Cu, In, Ga, and Se, it is very important to apply the 2700s process time for the second stage in order to produce high-efficiency device. The efficiency property of device was checked through solar-simulator (AM1.5G, 100 mW/cm2 at 25°C). In case the process time of the second stage was 2700s, efficiency was as following: 10.1%, V∞c: 0.53V, Jsc: 33.5 mA/cm3, fill-factor: 57.2%. The analysis results obtained in this study are expected to be useful for various domestic and overseas research which aim to make high-efficiency solar cells based on proper variation of the second-stage processing time. © 2011 Taylor & Francis Group, LLC.