chapter 3 sensors and platforms part 2 p2

Question 1

Passive microwave systems are based on a ………………….. that detects wavelengths in the ……………… region of the spectrum

Answer 1

type of radiometer

microwave

Question 2

Passive microwave systems are based on a type of radiometer that detects wavelengths in the microwave region of the spectrum. Because of the nature of microwave radiation

Answer 2

optical systems cannot be used for the detection of this range of wavelengths

Question 3

Passive microwave systems are based on a type of radiometer that detects wavelengths in the microwave region of the spectrum. Because of the nature of microwave radiation, optical systems cannot be used for the detection of this range of wavelengths. As with optical systems though, both …………………… systems are available

Answer 3

nonimaging and imaging

Question 4

The components of a microwave radiometer are

Answer 4

an antenna, receiver, and recording device

Question 5

Microwave energy emitted from Earth’s surface is collected by

Answer 5

an antenna

Question 6

Microwave energy emitted from Earth’s surface is collected by an antenna, converted by…………………… into a ……………………

Answer 6

a receiver into a signal

Question 7

Microwave energy emitted from Earth’s surface is collected by an antenna, converted by a receiver into a signal, and

Answer 7

recorded.

Question 8

The features of electromagnetic energy measured by microwave radiometers are

Answer 8

polarity, wavelength, and intensity

Question 9

The features of electromagnetic energy measured by microwave radiometers are polarity, wavelength, and intensity. These properties provide useful information about

Answer 9

the structure and composition of an object

Question 10

Most of the applications of passive microwave radiometers have been in

Answer 10

the fields of atmospheric and oceanographic research

Question 11

Most of the applications of passive microwave radiometers have been in the fields of atmospheric and oceanographic research. It has also proven to be an effective tool for the measurement of

Answer 11

soil moisture, an important parameter in studying vegetation

Question 12

By combining a number of detectors or radiometers into ………………….., it is possible to create a sensor that

Answer 12

detector arrays

can acquire a 2D image of an area

Question 13

There are three basic designs for imaging sensors

Answer 13

frame, pushbroom, and mechanical scanner.

Question 14

The first two designs are

Answer 14

similar.

Question 15

The frame sensor is a 2D array of detectors that acquires an entire image in

Answer 15

one exposure

Question 16

The first two designs are similar. The frame sensor is a ………… array of detectors that acquires an entire image in one exposure similar to the way

Answer 16

2D

a camera captures an image on film

Question 17

A pushbroom sensor is a ……….. . array that obtains

Answer 17

1D

an image one line at a time

Question 18

A pushbroom sensor is a 1D array that obtains an image one line at a time. Each new data line is added as the platform

Answer 18

moves forward

Question 19

Each new data line is added as the platform moves forward, building up

Answer 19

an image over time

Question 20

. A pushbroom sensor is a 1D array that obtains an image one line at a time. Each new data line is added as the platform moves forward, building up an image over time. In a mechanical scanner system the sensor acquires

Answer 20

only one or several pixels in any given instant

Question 21

In a mechanical scanner system the sensor acquires only one or several pixels in any given instant, but since the scanner

Answer 21

physically sweeps or rotates the sensor (a radiometer) or a mirror back and forth, an image is produced.

Question 22

This category of sensor (………………………)

Answer 22

passive visible, infrared and thermal imaging systems

Question 23

This category of sensor (passive visible, infrared and thermal imaging systems) contains ………………………..that have been deployed on

Answer 23

numerous instruments

a wide variety of platforms

Question 24

This category of sensor (passive visible, infrared and thermal imaging systems) contains numerous instruments that have been deployed on a wide variety of platforms and used for

Answer 24

many applications

Question 25

Most modern imaging systems are

Answer 25

multispectral (acquiring data for more than one limited spectral area)

Question 26

The recording of each discrete spectral sampling is referred to as

Answer 26

an image band or channel.

Question 27

Using image processing techniques, multiple (usually …………) bands selected from a

Answer 27

three

multispectral image database

Question 28

Using image processing techniques, multiple (usually three) bands selected from a multispectral image database can be combined to make

Answer 28

a single color composite image

Question 29

Active systems supply their own illumination energy which can be

Answer 29

controlled

Question 30

Some advantages active systems have over passive sensors are they

Answer 30

do not require solar illumination of surfaces or perfect weather conditions to collect useful data

Question 31

Some advantages active systems have over passive sensors are they do not require solar illumination of surfaces or perfect weather conditions to collect useful data. Consequently they can be deployed……………………. depending on

Answer 31

at night or in conditions of haze, clouds, or light rain (depending on the wavelength of the system).