1.1 What is Remote Sensing?
So, what exactly is remote sensing? For the purposes of this tutorial, we will use the
following definition:
\"Remote sensing is the science (and to some extent, art) of acquiring information about the Earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information.\"
1.1什么是遥感？
那么，究竟什么是遥感？这篇教程的目的，我们将使用下面的定义：
“遥感科学（在某种程度上，艺术）获取地球表面信息，而不必接触它。这是通过检测和记录反映或发出能量和处理，进行分析，并应用的信息。”
In much of remote sensing, the process involves an interaction between incident radiation and the targets of interest. This is exemplified by the use of imaging systems where the following seven elements are involved. Note, however that remote sensing also involves the sensing of emitted energy and the use of non-imaging sensors.
在许多遥感，过程包括入射辐射和感兴趣的目标之间的相互作用。这体现了在成像系统的使用下列七个因素有关。注意，然而，遥感还包括辐射能量的感知和非成像传感器的使用。
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1. Energy Source or Illumination (A) – the first requirement for remote sensing is to have an energy source which illuminates or provides electromagnetic energy to the target of interest.
2. Radiation and the Atmosphere (B) – as the energy travels from its source to the target, it will come in contact with and interact with the atmosphere it passes through. This interaction may take place a second time as the energy travels from the target to the sensor.
3. Interaction with the Target (C) - once the energy makes its way to the target through the atmosphere, it interacts with the target depending on the properties of both the target and the radiation.
4. Recording of Energy by the Sensor (D) - after the energy has been scattered by, or emitted from the target, we require a sensor (remote - not in contact with the target) to collect and record the electromagnetic radiation.
1。能源或照明（一）–遥感的第一个需求是有一个能量源的说明或提供电磁能量感兴趣的目标。
2。辐射和大气（B）–作为能量从源头到目标的移动，它会接触到与它穿过大气相互作用。这种相互作用可以一次为能从目标到传感器的传播发生。
3。与目标相互作用（C）-一旦能量使其通过空气到达目标，它与目标依靠目标的辐射特性。
4。通过传感器记录的能量（D）后能量被散射，或发出的目标，我们需要一个传感器（远程非接触目标）收集和记录的电磁辐射。
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5. Transmission, Reception, and Processing (E) - the energy recorded by the sensor has to be transmitted, often in electronic form, to a receiving and processing station where the data are processed into an image (hardcopy and/or digital).
6. Interpretation and Analysis (F) - the processed image is interpreted, visually and/or digitally or electronically, to extract information about the target which was illuminated.
7. Application (G) - the final element of the remote sensing process is achieved when we apply the information we have been able to extract from the imagery about the target in order to better understand it, reveal some new information, or assist in solving a particular problem. These seven elements comprise the remote sensing process from beginning to end. We will be covering all of these in sequential order throughout the five chapters of this tutorial, building upon the information learned as we go. Enjoy the journey!
5。发送，接收，处理（E）-传感器记录的能量被传输，通常以电子形式，来接收和处理站，数据处理成图像（硬拷贝和/或数字）。
6。解释和分析（F）-处理过的图像解释，视觉和/或数字或电子，提取目标进行照明的信息。
7。应用（G）-遥感过程的最后一个要素是实现当我们应用我们已经能够提取为目标的图像更好地了解它的信息，揭示了一些新的信息，或协助解决特定的问题。这七个要素包括遥感过程从开始到结束。我们将涵盖顺序，所有这些在本教程的五章，根据了解到的信息去。享受旅程！
1.2 Electromagnetic Radiation
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As was noted in the previous section, the first requirement for remote sensing is to have an energy source to illuminate the target (unless the sensed energy is being emitted by the target). This energy is in the form of electromagnetic radiation.
All electromagnetic radiation has fundamental properties and behaves in predictable ways according to the basics of wave theory. Electromagnetic radiation consists of an electrical field(E) which varies in magnitude in a direction perpendicular to the direction in which the radiation is traveling, and a magnetic field (M) oriented at right angles to the electrical field. Both these fields travel at the speed of light (c). Two characteristics of electromagnetic radiation are particularly important for understanding remote sensing. These are the wavelength and frequency.
1.2电磁辐射
正如前一节中提到的，遥感的第一个需求是有一个能量源照射目标（除非感觉能量被目标发射）。这种能量是以电磁辐射的形式。
所有电磁辐射的基本性质和行为在可预见的方式根据波浪理论的基础。电磁辐射是由一个电场（E），在垂直于其中的辐射传播方向的变化幅度，和磁场（M）面向电场成直角。这些领域以光的速度传播（C）。电磁辐射的特点是理解遥感尤为重要。这些都是波长和频率。
The wavelength is the length of one wave cycle, which can be measured as the distance between successive wave crests. Wavelength is usually represented by the Greek letter lambda (λ). Wavelength is measured in metres (m) or some factor of metres such as nanometres (nm, 10-9 metres), micrometres (µm, 10-6 metres) (µm, 10-6 metres) or
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centimetres (cm, 10-2 metres). Frequency refers to the number of cycles of a wave passing a fixed point per unit of time. Frequency is normally measured in hertz (Hz), equivalent to one cycle per second, and various multiples of hertz.
波长是一个波周期的长度，可以测量相邻波峰之间的距离。波长通常用希腊字母λ表示（λ）。波长是以米（m）或某些因素米如纳米（nm，10-9米），微米（µm，10-6米）（µm，10-6米或厘米（cm），10米）。频率是指一个波通过一个固定点的每单位时间的周期数。频率通常用赫兹（Hz），相当于每秒一个周期，和赫兹不同倍数。
Therefore, the two are inversely related to each other. The shorter the wavelength, the higher the frequency. The longer the wavelength, the lower the frequency. Understanding the characteristics of electromagnetic radiation in terms of their wavelength and frequency is crucial to understanding the information to be extracted from remote sensing data. Next we will be examining the way in which we categorize electromagnetic radiation for just that purpose.
因此，两成反比。波长越短，频率越高。波长越长，频率越低。了解他们的波长和频率的电磁辐射特性来理解信息是从遥感数据中提取关键的。下一步我们将检查方式的分类电磁辐射只是目的。
1.3 The Electromagnetic Spectrum
The electromagnetic spectrum ranges from the shorter wavelengths (including gamma and x-rays) to the longer wavelengths (including microwaves and broadcast radio waves). There are several regions of the electromagnetic spectrum which are useful for remote sensing.
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For most purposes, the ultraviolet or UV portion of the spectrum has the shortest wavelengths which are practical for remote sensing. This radiation is just beyond the violet portion of the visible wavelengths, hence its name. Some Earth surface materials, primarily rocks and minerals,fluoresce or emit visible light when illuminated by UV radiation.
1.3电磁波谱
电磁频谱范围从较短的波长（包括γ射线和X光）波长较长（包括微波和无线电波）。有电磁频谱可用于遥感的几个地区
对于大多数用途，紫外线或光谱紫外部分具有最短波长是实用的遥感。这种辐射是可见光波长的紫外部分，因此它的名字。一些地球表面材料，主要是岩石和矿物，荧光或发出可见光照射时，紫外辐射。
The light which our eyes - our \"remote sensors\" - can detect is part of the visible spectrum. It is important to recognize how small the visible portion is relative to the rest of the spectrum. There is a lot of radiation around us which is \"invisible\" to our eyes, but can be detected by other remote sensing instruments and used to our advantage. The visible wavelengths cover a range from approximately 0.4 to 0.7 µm. The longest visible wavelength is red and the shortest is violet. Common wavelengths of what we perceive as particular colours from the visible portion of the spectrum are listed below. It is important to note that this is the only portion of the spectrum we can associate with the concept of colours.
光，我们的眼睛我们的“遥控器”，可以检测部分的可见光谱。它是认识的可见部分相对于其余的频谱是多少重要。有很多的辐射在我们周围，“看不见”的眼睛，但可以通过其他遥感仪器用来检测我们的优势。可见光的波长覆盖范围从约0.4至0.7µM.最长的可见光波长是红色，最短的是紫罗兰色的。
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我们认为特定的颜色光谱的可见部分如下常见的波长。需要注意的是，这是唯一的频谱部分我们可以用颜色的概念联想重要。
Blue, green, and red are the primary colours or wavelengths of the visible spectrum. They are defined as such because no single primary colour can be created from the other two, but all other colours can be formed by combining blue, green, and red in various proportions. Although we see sunlight as a uniform or homogeneous colour, it is actually composed of various wavelengths of radiation in primarily the ultraviolet, visible and infrared portions of the spectrum. The visible portion of this radiation can be shown in its component colours when sunlight is passed through a prism, which bends the light in differing amounts according to wavelength.
蓝色，绿色，和红色可见光谱的原色或波长。他们是这样定义，因为没有一个单一的原色可以从其他两创建，但所有其他颜色可以结合形成蓝色，绿色，和红色的各种比例。虽然我们看到阳光均匀或不均匀的颜色，它实际上是由不同波长的辐射主要是紫外线，可见光和红外光谱的部分。这种辐射的可见部分可以在其组成部分所显示的颜色当太阳光通过棱镜，使光在不同的金额根据波长。
The next portion of the spectrum of interest is the infrared (IR) region which covers the wavelength range from approximately 0.7 µm to 100 µm - more than 100 times as wide as the visible portion! The infrared region can be divided into two categories based on their radiation properties - the reflected IR, and the emitted or thermal IR. Radiation in the reflected IR region is used for remote sensing purposes in ways very similar to radiation in the visible portion. The reflected IR covers wavelengths from approximately 0.7 µm to 3.0 µm. The thermal IR region is quite different than the visible and reflected IR portions, as this energy is essentially the radiation that is emitted from the Earth's surface in the form of heat. The
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thermal IR covers wavelengths from approximately 3.0 µm to 100 µm.
感兴趣的频谱的一部分的红外（IR）的区域，覆盖的波长范围从大约0.7米至100米µµ-超过100倍宽的可见部分！红外区可以分为基于其辐射特性-反射红外两类，与发射或热红外。在反射红外辐射用于遥感目的的方式辐射非常相似的可见部分。反射红外线覆盖波长从约0.7米到3米µµ热红外波段比可见光和红外部分的反映完全不同，这是本质上的辐射能量以热的形式被从地球表面发射。热红外波长覆盖从大约3µM 100µM.
The portion of the spectrum of more recent interest to remote sensing is the microwave region from about 1 mm to 1 m. This covers the longest wavelengths used for remote sensing. The shorter wavelengths have properties similar to the thermal infrared region while the longer wavelengths approach the wavelengths used for radio broadcasts. Because of the special nature of this region and its importance to remote sensing in Canada, an entire chapter (Chapter 3) of the tutorial is dedicated to microwave sensing.
对更近期的光谱遥感部分微波范围从1毫米到1米。这套最长的波长用于遥感。较短的波长的性质与热红外区域在较长的波长的方法用于无线电广播的波长。因为该地区遥感在加拿大其重要性的特殊性，整个一章（3章）的教程是专门为微波遥感。
1.4 Interactions with the Atmosphere
Before radiation used for remote sensing reaches the Earth's surface it has to travel through some distance of the Earth's atmosphere. Particles and gases in the atmosphere can affect the incoming light and radiation. These effects are caused by the mechanisms of scattering and absorption.
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Scattering occurs when particles or large gas molecules present in the atmosphere interact with and cause the electromagnetic radiation to be redirected from its original path. How much scattering takes place depends on several factors including the wavelength of the radiation, the abundance of particles or gases, and the distance the radiation travels through the atmosphere. There are three (3) types of scattering which take place.
1.4与大气的相互作用
在用于遥感辐射到达地球的表面有旅行通过一定距离的地球大气层。大气中的颗粒物和气体会影响入射光和辐射。这些影响是通过散射和吸收的机制造成的。
散射发生在颗粒或大分子气体在大气中的相互作用、电磁辐射引起转从原来的路径。散射发生多少取决于几个因素，包括辐射的波长，颗粒或气体的丰度，和距离的辐射穿过大气。有三（3）的散射发生的类型。
Rayleigh scattering occurs when particles are very small compared to the wavelength of the radiation. These could be particles such as small specks of dust or nitrogen and oxygen molecules. Rayleigh scattering causes shorter wavelengths of energy to be scattered much more than longer wavelengths. Rayleigh scattering is the dominant scattering mechanism in the upper atmosphere. The fact that the sky appears \"blue\" during the day is because of this phenomenon. As sunlight passes through the atmosphere, the shorter wavelengths (i.e. blue) of the visible spectrum are scattered more than the other (longer) visible wavelengths. At sunrise and sunset the light has to travel farther through the atmosphere than at midday and the scattering of the shorter wavelengths is more complete; this leaves a greater proportion of the longer wavelengths to penetrate the atmosphere.
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瑞利散射发生在粒子相比是非常小的辐射的波长。这可能是粒子如小微尘或氮和氧分子。瑞利散射导致更短的波长的能量被分散的多波长较长。瑞利散射是主要的散射机制在高层大气中。事实上，天空出现“白天蓝”是因为这一现象。当阳光穿过大气层，较短的波长（即蓝色）的可见光谱的分布比其他（长）可见光波长。在日出和日落的光线通过大气层更远比中午和较短的波长的散射更完整；这让更大比例的较长的波长穿透大气层。
Mie scattering occurs when the particles are just about the same size as the wavelength of the radiation. Dust, pollen, smoke and water vapour are common causes of Mie scattering which tends to affect longer wavelengths than those affected by Rayleigh scattering. Mie scattering occurs mostly in the lower portions of the atmosphere where larger particles are more abundant, and dominates when cloud conditions are overcast.
Mie散射发生在颗粒差不多大小的辐射波长相同。灰尘，花粉，烟雾和水蒸气是米氏散射，容易影响波长比瑞利散射影响较长的常见原因。Mie散射主要发生在较大的颗粒更丰富的氛围下部分，并占主导地位时，云条件阴。Mie散射发生在颗粒差不多大小的辐射波长相同。灰尘，花粉，烟雾和水蒸气是米氏散射，容易影响波长比瑞利散射影响较长的常见原因。Mie散射主要发生在较大的颗粒更丰富的氛围下部分，并占主导地位时，云条件阴。
The final scattering mechanism of importance is called nonselective scattering. This occurs when the particles are much larger than the wavelength of the radiation. Water droplets and large dust particles can cause this type of scattering. Nonselective scattering gets its name from the fact that all wavelengths are scattered about equally. This type of scattering causes fog and clouds to appear white to our eyes because blue, green, and red light are all scattered in approximately equal quantities (blue+green+red light = white light).
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重要的最后散射机制称为非选择性散射。这是发生在颗粒比辐射的波长大得多。水滴和大颗粒灰尘会导致这种类型的散射。非选择性散射从事实上所有波长分散同样得名。这种类型的散射引起的雾和云出现白色眼睛因为蓝色，绿色和红色的光，都是分散的数量大致相等（蓝色+绿色+红色光=白光）。
Absorption is the other main mechanism at work when electromagnetic radiation interacts with the atmosphere. In contrast to scattering, this phenomenon causes molecules in the atmosphere to absorb energy at various wavelengths. Ozone, carbon dioxide, and water vapour are the three main atmospheric constituents which absorb radiation. Ozone serves to absorb the harmful (to most living things) ultraviolet radiation from the sun. Without this protective layer in the atmosphere our skin would burn when exposed to sunlight. You may have heard carbon dioxide referred to as a greenhouse gas. This is because it tends to absorb radiation strongly in the far infrared portion of the spectrum - that area associated with thermal heating - which serves to trap this heat inside the atmosphere. Water vapour in the atmosphere absorbs much of the incoming longwave infrared and shortwave microwave radiation (between 22µm and 1m). The presence of water vapour in the lower atmosphere varies greatly from location to location and at different times of the year. For example, the air mass above a desert would have very little water vapour to absorb energy, while the tropics would have high concentrations of water vapour (i.e. high humidity). Because these gases absorb electromagnetic energy in very specific regions of the spectrum, they influence where (in the spectrum) we can \"look\" for remote sensing purposes. Those areas of the spectrum which are not severely influenced by atmospheric absorption and thus, are useful to remote sensors, are called atmospheric windows. By comparing the characteristics of the two most common energy/radiation sources (the sun and the earth) with the atmospheric windows available to us, we can define those wavelengths that we can use most effectively for remote sensing. The visible portion of the spectrum, to which our eyes are most sensitive,
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corresponds to both an atmospheric window and the peak energy level of the sun. Note also that heat energy emitted by the Earth corresponds to a window around 10 µm in the thermal IR portion of the spectrum, while the large window at wavelengths beyond 1 mm is associated with the microwave region.
吸收其他主要机构在工作时电磁辐射与大气的相互作用。相反，散射，这种现象导致大气中的分子在不同波长的吸收能量。臭氧，二氧化碳，水蒸气是三个主要的大气成分的吸收辐射。臭氧能吸收有害（对大多数生物）来自太阳的紫外线辐射。没有这个保护层在大气中的我们的皮肤暴露在阳光下会燃烧。你可能听说过二氧化碳被称为温室气体。这是因为它会吸收辐射强在光谱的远红外部分，面积与热相关的用于捕获这个热场内气氛。大气中的水蒸气吸收的入射长波、短波红外微波辐射（22µ米和100万之间）。在低层大气中的水蒸汽的存在很大不同地点和不同时期的一年。例如，空气质量在沙漠会有很少的水蒸气吸收能量，而热带地区会有高浓度的水蒸气（即高湿度）。因为这些气体吸收电磁能量的频谱在特定的地区，他们的影响在哪里（在谱）我们可以“看”的遥感的目的。这些地区不被大气吸收，从而严重影响光谱遥感传感器，是有用的，被称为“大气窗口。通过比较这两种最常见的能量/辐射源的特点（太阳和地球）提供给我们的大气窗口的波长，我们可以定义我们可以最有效地利用遥感。光谱的可见部分，而我们的眼睛是最敏感的，对应于一个大气窗口和太阳的峰值能量水平。还要注意热量由地球发射对应于光谱的红外部分窗口约10µm，而大窗口波长超过1毫米与微波区相关。
Now that we understand how electromagnetic energy makes its journey from its source to the surface (and it is a difficult journey, as you can see) we will next examine what happens to that radiation when it does arrive at the Earth's surface.
现在我们了解电磁能量使它的旅程从源头到表面（这是一个艰难的旅程，你可以看到）我们会研究，辐射会发生什么当它到达地球表面。
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专业英语遥感相关词汇
prisim棱镜 category（生物）类别 property性质，特性 reflect反射
scatter散射 thermal热的 essentially本质上，根本上 tutoria 指导的 particle微粒 mechanism机制，机理 molecule分子 abundance大量 redirect改变方向 absorption吸收作用 contrast ozone臭氧 constituent成分，要素 carbon dioxide二氧化碳 tropic热带的 concentration集中 atmospheric window大气窗口 correspond to相当
于 Rayleigh scattering瑞利散射 speck小颗粒 nitrogen氧 dominant占优势 proportion比例 penetrate穿过 Mie scattering米氏散射 pollen花粉 water vapour水蒸
气 water droplet水滴 nonselective scattering无选择性散射 fundamental基本的 predictable可预测的 electrical field电场 magnitude振幅 perpendicular垂直的
magnetic field磁场 orient朝向 right angle直角
frequency频率 measure测量 successive连续的 crest峰 nanometre纳米
micrometre微米 refers to引用 equivalent相当于 multiple倍数 formula公式，准则
inversely相反地 crucial重要的，决定性的
in terms of在...方面，就...而言 categorize把...归类 in contact with接触 reflcet反射 emit发射 process处理 involve包含 interaction相互作用 incident入射 radiation辐
射 exempily示范 sensor传感器 source来源 reception接收 illuminate照明 electromagnetic电磁的 transmission传输 interpretation解译 extract摘录，提取 application应用 reveal显示 assist帮助，协助 bounces off弹回 specular reflection镜面
反射 diffuse reflection漫反射
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