Brain-computer interfaces are sophisticated signal processing systems, which directly operate on neuronal signals to identify specific human intents. These systems can be applied to overcome certain disabilities or to enhance the natural capabilities of human beings. The visual P300 mind-speller is a prominent one among them, which has opened up tremendous possibilities in movement and communication applications. Today, there exist many state-of-the-art visual P300 mind-speller implementations in the literature as a result of numerous researches in this domain over the past 2 decades. Each of these systems can be evaluated in terms of performance metrics like classification accuracy, information transfer rate, and processing time. Various classification techniques associated with these systems, which include but are not limited to discriminant analysis, support vector machine, neural network, distance-based and ensemble of classifiers, have major roles in determining the overall system performances. The significance of a proper review on the recent developments in visual P300 mind-spellers with proper emphasis on their classification algorithms is the key insight for this work. This article is organized with a brief introduction to P300, concepts of visual P300 mind-spellers, the survey of literature with special focus on classification algorithms, followed by the discussion of various challenges and future directions.

中文翻译：

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Visual P300 Mind-Speller 脑机接口：了解最近的发展，特别关注分类算法

脑机接口是复杂的信号处理系统，它直接对神经元信号进行操作以识别特定的人类意图。这些系统可用于克服某些残疾或增强人类的自然能力。视觉P300思维拼写器是其中的一个突出的，它为运动和通信应用开辟了巨大的可能性。今天，由于过去 20 年对该领域的大量研究，文献中存在许多最先进的视觉 P300 思维拼写器实现。这些系统中的每一个都可以根据分类准确度、信息传输率和处理时间等性能指标进行评估。与这些系统相关的各种分类技术，其中包括但不限于判别分析、支持向量机、神经网络、基于距离的分类器和集成分类器，在确定整体系统性能方面发挥着重要作用。对视觉 P300 思维拼写器的最新发展进行适当审查并适当强调其分类算法的重要性是这项工作的关键见解。本文的组织方式包括对 P300 的简要介绍、视觉 P300 思维拼写器的概念、特别关注分类算法的文献调查，然后是对各种挑战和未来方向的讨论。对视觉 P300 思维拼写器的最新发展进行适当审查并适当强调其分类算法的重要性是这项工作的关键见解。本文的组织方式包括对 P300 的简要介绍、视觉 P300 思维拼写器的概念、特别关注分类算法的文献调查，然后是对各种挑战和未来方向的讨论。对视觉 P300 思维拼写器的最新发展进行适当审查并适当强调其分类算法的重要性是这项工作的关键见解。本文的组织方式包括对 P300 的简要介绍、视觉 P300 思维拼写器的概念、特别关注分类算法的文献调查，然后是对各种挑战和未来方向的讨论。