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一、综合分析题

1、这幅图表示的是一种经过何种图像增强方法处理以后的图像直方图?

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2、根据下图说明水体的反射光谱特征。

3、说明绿色植物的光谱特点

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4、说明此图所表示的含义。

5、根据下图,解释像点位移。

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6、At what one wavelength does there appear to be maximum separability of the five

Non-vegetated Classes; the five Vegetated Classes?

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7、Note that clouds, snow on the mountains, and light desert soils (right center) all appear white in the false color composite image and the three black and white filter images. There are several

areas of bright to medium red in the f.c. composite. Try to find their corresponding locations in the three filter images and be aware of their gray levels.

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Green Red

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Photo IR Bands False Color IR

8、This Landsat Thematic Mapper image segment has a band =>colour assignment of:

A.R,G,B => 1,2,3

B.R,G,B => 2,3,1

C.R,G,B => 5,4,3

Choose the band-to-colour assignment (A, B or C, above) that fits this Landsat TM satellite image colour composite.

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The answer is C.

A. No.

Band 1, which is the shortest wavelength band of the TM has the best water penetration of these three bands and would show sediment best. If assigned as red (as in this choice), it would depict water in red tones.

B. No.

Band 2, which is green-sensitive, would depict (green) vegetation in its assigned colour of red. But we see that the lowland vegetation (bottom portion of image) is shown as green.

C. Yes.

Of these three bands the lowest wavelength band (3), which has the best volume reflection from water assigned as blue, indeed shows water as blue. Green vegetation is most reflective (of these three bands) in band 4, and with its green assignment does show vegetation as green.

相关知识:

Notice the very rough and convoluted shoreline in the pink areas in the top half of the image and how it contrasts with the relatively smooth shoreline in the green areas in the bottom part of the image. This is a sure indication that the rocks of the Canadian shield are exposed in the pink areas, while there is substantial overburden (soil) in the green areas.

9、The diagonal white line at the top right of the image is:

A.paved road

B.contrail

C.hydro line

D.gravel road

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E.

The answer is B.

A. No.

A road wouldn't be as straight as this line, nor would it cross water bodies without a bridge!

B. Yes.

An aircraft condensation trail is not limited to land or water. The parallel contrail shadow just above it confirms this feature and also gives a mechanism for calculating the altitude of the contrail (the date and time of the image identifies the sun angle and the horizontal offset of contrail and shadow can be measured from the image).

C. No.

Usually a hydro line is visible because the right-of-way has been cleared of vegetation. But it would not be visible while crossing water bodies, as it is here.

D. No.

The same reasoning goes here as for a paved road. A road wouldn't be as straight as this line, nor would it cross water bodies without a bridge!

相关知识:

By knowing the time that the satellite image was recorded, we can determine the sun angle (above the horizon). With that parameter, as well as the horizontal distance on th image between an object (such as the contrail) and its shadow, we can calculate the height of that object above the Earth's surface. This is the relationship:

h = height of the object above the Earth's surface

d = horizontal distanc

e between object and shadow

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s = angle of the sun above the horizon

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h = d ? tan s

10、Match the band combinations with their respective images. Landsat TM Band Combinations

?3, 2, 1

?3, 4, 5

?4, 3, 2

?5, 4, 3

A - 3, 4, 5

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B - 3, 2, 1

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C - 4, 3, 2

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D - 5, 4, 3

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相关知识:

When looking at image "C": the dark brown areas in the middle of the image are forest fire scars, the white areas at the bottom of the image are snow-covered mountain tops, the light

blue line across the middle of the image is a river. There is a diagonal line of small clouds (and cloud shadows) across the top right of the image. The small black areas are lakes. 3, 2, 1

This combination is the only one that includes band 1 with its blue sensitivity. Therefore, this combination of bands and colour assignments is the closest that we can come to making a real-colour simulation.

TM band 1 is the band most affected by atmospheric scattering, so it shows clouds, haze and smoke the best.

3,4,5

The red-sensitive band (#3) that has a little water penetration ability is coded as red in this band combination. The other two bands have no significant water penetration ability, so any sediment-laden water body should appear as red.

4,3,2

This is the simulation of the traditional of false-colour infrared film which shows healthy vegetation in shades of red.

5,4,3

The red-sensitive band (#3) which has a little water penetration ability is coded as blue in this band combination. The other two bands have no significant water penetration ability, so any sediment-laden water body should appear as blue.

Landsat 5 Thematic Mapper spectral band definitions:

Band 1: 0.45-0.52 micrometres (blue-green)

Band 2: 0.52-0.60 micrometres (green)

Band 3: 0.63-0.69 micrometres (red)

Band 4: 0.76-0.90 micrometres (near infrared)

Band 5: 1.55-1.75 micrometres (near infrared)

Band 6: 10.4-12.5 micrometres (thermal infrared)

Band 7: 2.08-2.35 micrometres (shortwave infrared)

11、How well do you know your histograms? Match the histogram to each image.

A histogram is a graphical way of representing statistics related to image brightness. A one dimensional histogram, like the ones shown here, depict the amount of image area (vertical axis) that corresponds to particular brightness values (horizontal axis). Analysis of the histogram of an image allows the interpreter to objectively identify the pixel population of the image as classified into brightness levels.

Image 1

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C Image 2

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B Image 3

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D

Image 4

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相关知识

A histogram or "frequency distribution" of an image allows the analyst to:

1) detect some possible problems in the processing of a digital image,

2) plan appropriate enhancements for the visual interpretation of an image,

3) plan suitable classification schemes for an image or image portion,

4) plan suitable ground truthing in support of image classification,

5) prepare for appropriate mosaicking methods of several images,

6) and more!

Image 5

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B Image 6

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Image 7

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Hint for Image 2: There appears to be a full range of greys in this image.

Hint for Image 3:There are two distinct shades of mid-grey in this image, each represented by the two large fields. The light-toned road in the bottom of the image has a small relative area and a narrow range of grey levels.

Hint for Image 4: The grey levels in this image are all mid-level, with a complete absence of lighter shades.

Hint for Image 5:More than half of the area in this image has a narrow range of dark tones representing the water. The land contains a wide range of mid to high tones.

Hint for Image 6: Most of the area of this image is taken with a wide range of mid to high tones representing the land. On the water side, a small fraction of the image is covered with a narrow range of dark tones.

Hint for Image 7: Most of the area of this image is taken with a wide range of mid to high tones representing the land. On the water side, a small fraction of the image is covered with a narrow range of mid-grey tones.

13、Do you know your image enhancements?

Visual interpretation of images often make use of image enhancement to make certain features more prominent and simpler to recognize. But the specific enhancement to be used depends on the feature to be interpreted and the nature of the imagery.

Original Imag

Which enhanced image below (A, B, C or D) is the result of:

1. contrast stretch enhancement

2. high pass filter enhancement

3. intensity slicing enhancement

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Hint for Contrast Stretch:

From the CCRS Glossary:

"A process in which the range of brightness levels of an image is expanded to use the full brightness range of the recording film or display device."

The "stretched" image shows dark areas even darker, and bright areas brighter.

Hint for High Pass Filter:

From the CCRS Glossary:

"A type of spatial filter that uses a convolution filter to produce an image that emphasizes areas of fine spatial detail (e.g. edges)."

The enhanced image should look sharper/crisper, with better defined lines.

Hint for Intensity Slicing:

This process involves substantially reducing or grouping the number of discrete grey levels from (say) 256 to 16. The resulting grey levels can be displayed as unique shades of grey or as discrete colours.

14、Match the histograms below (blue letters) to the marked sites on the image. The graphical plots represent two-dimensional histograms or the frequency of occurrence of brightness levels in TM bands 3 and 5 for various sites in the accompanying image.

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Did You Know ? A spectral signature can have as many dimensions as there are individual spectral bands recorded. The more and narrower the bands, the better a feature's "signature" is identified. With modern sensors, it is quite common to have hundreds of spectral bands, each very narrow and contiguous with neighbouring bands. These are "hyperspectral" sensors. ints

Site 1: There is a large variation in the green tones and very little in the red, so the histogram should be quite spread out in the vertical axis but not much in the horizontal. Site 2: Compared to site 1, this site shows a much more limited range of green tones, so the histogram spread will be noticeably less in the vertical direction. The average red values appear to be the same as for site 1.

Site 3: This site shows a very narrow range of dark tones, especially in the green, and therefore one would expect to see a histogram with very limited spread, close to the origin. Site 4: At this location, the range of brightnesses is large, with a high mean value in both red and green. One would expect to see a large spread in the histogram, with the mean point well away from the origin.

Site 5:The range of brightness for this feature is very narrow, so the histogram will show a very small plot. The average green value is very low, while the red is very high.

Site 6: The green brightness range is very large here, but the red range is not. The mean green value is very high, much more than for the red. As a result, the histogram should be much wider in the vertical than in the horizontal dimension and the central point in the histogram well offset in the vertical direction.

Site 7: There is a good range of green and red tones at this site but the mean value of the red is noticeably higher than for the green. Thus the histogram should be located much closer to the horizontal axis than the vertical.

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A - image section #3

B - image section #2

C - image section #4

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D - image section #7

E - image section #5

F - image section #6

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G - image section #1

15、The areas of water in this image are mostly a speckled grey tone, but with large sections of black. These black areas are:

A.Oil slicks on the water surface.

B.Shadows from the hills on the islands.

C.Wind sheltering by the land areas.

The answer is C.

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A. No.

It would take an extraordinary amount of oil and an incredible current and wave action to distribute oil among all those islands in the pattern seen here.

B. No.

There is no evidence of very tall hills on the islands. The incidence angle from the satellite would not be blocked to that extent by even very tall hills or mountains. The shape of the black water areas do not conform to prospective hills on the islands.

C. Yes.

The brighter areas of water are due to wind-generated waves which cause a brighter radar reflection. Where the land shelters the water surface from wind, the lesser wind speed reduces the magnitude of the waves and the water surface acts like a mirror, reflecting the radar beam in a specular manner — away from the radar antenna. This appears as areas of little or no radar return on the image: a black tone.

16、The radar beam that illuminated this scene came from the:

A.Top

B.Bottom

C.Right

D.Left

Choose A, B, C or D

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A. No.

You just guessing, are you?

B. No.

There is absolutely no evidence for this!

C. No.

Another wild guess!

D. Yes. The answer is D.

Evidence for this comes from a number of image features. At the top, as the hills are illuminated by the radar, they show a brighter reflection from the radar-facing side which are the left side slopes. At the bottom right are two long piers jutting out into the water. These piers show a radar shadow to their right, which indicates radar illumination from the left.

二、问答题

1.什么是遥感?国内外对遥感的多种定义有什么异同点?

2.根据你对遥感技术的理解,谈谈遥感技术系统的组成。

3.什么是散射?大气散射有哪几种?其特点是什么?

4.微波遥感的特点有哪些?

5.遥感影像变形的主要原因是什么?

6.遥感影像地图的主要特点是什么?

7.遥感图像计算机分类中存在的主要问题是什么?

8.简要回答计算机辅助遥感制图的基本过程。

9.谈谈你对遥感影像解译标志的理解。

10.何谓遥感、地理信息系统、全球定位系统?简要回答三者之间的相互关系与作用。

11.谈谈你对遥感影像解译标志的理解。

12.遥感技术识别地物的原理。

13.MSS影象的波段是如何划分的?各个波段的主要用途是什么?

14.TM影象的波段是如何划分的?各个波段的重要用途是什么?

15.对比MSS和TM的波段划分,分析其异同。

16.SPOT影象的波段是如何划分的?各个波段的重要用途是什么?

17.按传感器的工作波段可把遥感划分为哪几种类型?

18.简述遥感在地质学研究中的应用。

19.简述各种类型电磁波的性质和用途。

20.太阳辐射的光谱特性有哪些?

21.试述NOAA气象卫星的轨道特征和卫星传感器AVHRR各通道的作用。

22.在标准假彩色合成图象上怎样识别地物类别?

23.试述遥感在资源清查与环境监测中的作用。

24.遥感数字图象处理有几种主要方法?简述它们的原理和特点。

25.遥感技术识别地物的原理。

26.按传感器的工作波段可把遥感划分为哪几种类型?

27.太阳辐射的光谱特性有哪些?

28.说明美国陆地卫星MSS图像的光谱效应。

29.气球遥感的特点及局限性。

30.利用航空 (用飞机作遥感平台)热红外遥感进行环境监测,选择一天中什么时间进行飞行其效

果最好?为什么?

31.试述遥感在资源清查与环境监测中的作用。

32.遥感数字图象处理有几种主要方法?简述它们的原理和特点。

33.根据传感器的工作波段可将遥感分为哪几类?

34.气球遥感的特点及局限性。

35.彩红外像片的优点有哪些?

36.在标准假彩色合成图象上怎样识别地物类别?

37.黑白像片的判读方法主要有哪些?

38.中心投影的成像特征有哪些?

39.什么是基尔霍夫定律?其遥感意义是什么?

40.什么是大气窗口?谈谈你对大气窗口的认识和理解。

41.遥感图象的分辨率有几种描述?其意义各是什么?

42.什么是维恩位移定律?

43.略谈小波分析在遥感图象分类中的应用。

44.简述遥感数字影像增强处理的目的,例举一种增强处理方法,说明其原理和步骤。

45.非监督分类和监督分类的本质区别是什么?

46.利用雷达探测地物的机理及其优势。

47.光机扫描成像与CCD成像的比较。

48.晴空时大气对可见光遥感和红外遥感的影响有何特点?

49.我国“风云一号”系列气象卫星是极轨气象卫星,其中“风云一号C星”及

“风云一号D星”携带的多通道可见红外扫描辐射计(MVISR) 有10个通道,各通道波

长如下表。请谈谈这些探测波段在陆地地表遥感中的用途。

表1:风云1-C、D多通道可见红外扫描辐射计(MVISR)各个波段的波长范围

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50.遥感的基本概念是什么?

51.遥感探测系统包括哪几个部分?

52.作为对地观测系统,遥感与常规手段相比有什么特点?

53.中国遥感事业的成就表现在哪些方面,有何特点?

54.在真空中,电磁波速为3×108m/s。

(1)可见光谱的波和范围从约3.8×10-7m的紫色光到约7.6×10-7m的红色

光,其对应的频率范围为多少?

(2)X射线的波长范围约5×10-9~1.0×10-11m,其对应的频率范围又是多少?

(3)短波无线电的频率范围约为1.5MHz~300MHz,其对应的长波范围是多少?

55.阐述辐照度I,辐射度M和辐身亮度L的物理意义,其共同点和区别是什么?

56.在地球上测得太阳的平均辐照度I=1.4×103W/m2,设太阳到地球的平均距离约为1.5×1011m。试求太阳的总辐射能量。

57.假定恒星表面的辐射与太阳表面辐射一样都遵循黑体辐射规律。如果测得到太阳

辐射波谱的λ太max=0.51μ

m,北极星的λ北max=0.35

μ

m,试计算太阳和北极星的

表面温度及每单位表面积上所发射出的功率是多少?

58.已知日地平均距离为天文单位,1天文单位≈1.496×103m,太阳的线半径约为6.96×105km:

(1)通过太阳常数I0,计算太阳的总辐射通量E;

(2)由太阳的总辐射通量E,计算太阳的辐射出射度M。

59.大气的散射现象有几种类型?根据不同散射类型的特点分析可见光遥感与微波遥感的区别,说明为什么微波具有穿云透雾能力而可见光不能。

60.对照书内卫星传感器表中所列波段区间和大气窗口的波段区间,理解大气窗口对于遥感探测的重要意义。

61.综合论述太阳辐射传播到地球表面又近回到遥感传感器这一整个过程中所发生的物理现象。

62.从地球辐射的分段特性说明为什么对于卫星影像解译必须了解地物反射波谱特性。

63.列举几种可见光与近红外波段植被、土壤、水体、岩石的地物反射波谱曲线实例。

64.主要遥感平台是什么,各有何特点?

65.摄影成像的基本原理是什么?其图像有什么特征?

66.扫描成像的基本原理是什么?扫描图像与摄影图像有何区别?

67.微波成像与摄影、扫描成像有何本质的区别?

68.如何评价遥感图像的质量?

69.熟悉颜色的三个属性。明度、色调、饱和度,选取自然界的某些颜色例如:树