Rosbridge: ROS for Non-ROS Users 笔记

Point cloud

From Wikipedia

A point cloud is a set of data points in some coordinate system.

In a three-dimensional coordinate system, these points are usually defined by X, Y, and Z coordinates, and often are intended to represent the external surface of an object.

Point clouds may be created by 3D scanners. These devices measure a large number of points on an object's surface, and often output a point cloud as a data file. The point cloud represents the set of points that the device has measured.

Data acquisition

From Wikipedia

Data acquisition is the process of sampling signals that measure real world physical conditions and converting the resulting samples into digital numeric values that can be manipulated by a computer. Data acquisition systems, abbreviated by the acronyms DAS or DAQ, typically convert analog waveforms into digital values for processing. The components of data acquisition systems include:

• Sensors, to convert physical parameters to electrical signals.
• Signal conditioning circuitry, to convert sensor signals into a form that can be converted to digital values.
• Analog-to-digital converters, to convert conditioned sensor signals to digital values.

POSIX

POSIX表示可移植操作系统接口（Portable Operating System Interface ，缩写为 POSIX ），POSIX标准定义了操作系统应该为应用程序提供的接口标准，是IEEE为要在各种UNIX操作系统上运行的软件而定义的一系列API标准的总称，其正式称呼为IEEE 1003，而国际标准名称为ISO/IEC 9945。

WebSocket

在 WebSocket API，浏览器和服务器只需要做一个握手的动作，然后，浏览器和服务器之间就形成了一条快速通道。两者之间就直接可以数据互相传送。在此WebSocket 协议中，为我们实现即时服务带来了两大好处：

1. Header
   互相沟通的Header是很小的-大概只有 2 Bytes
2. Server Push
   服务器的推送，服务器不再被动的接收到浏览器的request之后才返回数据，而是在有新数据时就主动推送给浏览器。

WebSocket API最伟大之处在于服务器和客户端可以在给定的时间范围内的任意时刻，相互推送信息。WebSocket并不限于以Ajax(或XHR)方式通信，因为Ajax技术需要客户端发起请求，而WebSocket服务器和客户端可以彼此相互推送信息；XHR受到域的限制，而WebSocket允许跨域通信。
WebSocket为指定目标创建，用于双向推送消息。

---

知乎：

1. 被动性，当服务器完成协议升级后（HTTP->Websocket），服务端就可以主动推送信息给客户端啦。
2. 只需要经过一次HTTP请求，就可以做到源源不断的信息传送了。（在程序设计中，这种设计叫做回调，即：你有信息了再来通知我，而不是我傻乎乎的每次跑来问你）

Serialized JSON objects 序列化的JSON对象

Mobile manipulator

Mobile manipulator is nowadays a widespread term to refer to robot systems built from a robotic manipulator arm mounted on a mobile platform. Such systems combine the advantages of mobile platforms and robotic manipulator arms and reduce their drawbacks. For instance, the mobile platform extends the workspace of the arm, whereas an arm offers several operational functionalities.
General system composition:

• Mobile platform
• Robot manipulator
• Vision
• Tooling

Common Platform

Common Platform is a collaboration between IBM, GlobalFoundries, and Samsung Electronics developed to implement a common process technology across all three companies' semiconductor manufacturing facilities.

Web GL

WebGL (Web Graphics Library) 是一个用以渲染交互式3D和2D图形的无需插件且兼容下一代浏览器的 JavaScript API。WebGL 引用的JavaScript API遵守OpenGL ES2.0规范，通过HTML5中 元素实现功能。

Custom controllers

Crowdsourcing

Crowdsourcing is a specific sourcing model in which individuals or organizations use contributions from Internet users to obtain needed services or ideas. Crowdsourcing was coined in 2005 as a portmanteau of crowd and outsourcing. This mode of sourcing to divide work between participants to achieve a cumulative result was already successful before the digital age (i.e., "offline").

LCM

Lightweight Communications and Marshalling (LCM)
LCM is a set of libraries and tools for message passing and data marshalling(数据编组), targeted at real-time systems where high-bandwidth and low latency are critical. It provides a publish/subscribe message passing model and automatic marshalling/unmarshalling code generation with bindings for applications in a variety of programming languages.

• marshalling：
  编组（marshalling）是一个将负责对象转换成字节流的过程，然后在使用反过程----反编组将字节流转换成对象。