Example SURE 339
Exam Questions
- In extracting information from imagery, the analyst
requires explicit (or formal) knowledge of the landscape.
Why?
- Discuss the concept of transparency as it affects the
commercial remote sensing community. What is shutter
control?
- Describe the two important remote sensing relationships
defined by the energy balance equation.
- Temporal effect (or spatial effect) influence spectral
response patterns. Explain and give a clear example.
- Energy of a quantum is given as Q = (hc)/l. Describe the
significance of this property as it applies to remote
scanning. What is the significance of Wien's Displacement
Law as it applies to remote sensing?
- What is the difference between an active and a passive
sensor? Give an example of each.
- Describe the cause and effects of Rayleigh scatter.
Describe the cause and effects of nonselective scatter.
Describe the important consequences that scattering has
on remote sensing.
- What is refraction and its causes? Describe the
importance of atmospheric absorption on the selection of
the remote sensor. What is absorption?
- What is the difference between a specular and diffuse
reflector?
- What is the difference between spectral and spatial
resolution? Describe radiometric resolution. Describe how
resolution is measured in an image.
- Films are described by their spectral sensitivity.
Describe and give an example.
- What is the characteristic curve and why is it important?
- What is the difference between band interleaved by line
(BIL) and band sequential (BSQ) data formats? Describe
the data format band interleaved by pixel (BIP).
- Identify and describe two of the advantages of
multispectral scanner data over photography. What is the
difference between the across-track and along-track
multispectral scanner?
- Identify the advantages of a linear scanner array over
mirror scanning systems. What are the disadvantages of a
linear scanner array? What are the advantages of pushbroom
scanning over whiskbroom scanning?
- What is a diffusion grating?
- Define dwell time.
- What is the instantaneous field of view? What are the
advantages of a large IFOV.
- In image interpretation, texture is used to identify
features. What helps determine the texture within an
image? Describe how shadow affects image interpretation.
- Describe the typical problems the image interpreter
addresses when delineating observed regions on imagery.
- Describe how image acquisition was performed with the Corona spy
satellite system.
- Describe the process by which Landsat multispectral data
are captured. Why is the repeat cycle different between
Landsat-1, -2, and -3 as compared to Landsat-4 and -5?
What configuration was employed with Landsat-4 and -5 to
increase the repeat cycle? The Landsat MSS image scene
initially contains skew. What is it and what are the
effects on the image format upon removing the skew
effect?
- What was the RBV system on Landsat-1, -2, and -3? How was
the image captured? What was the advantage of the RBV
sensor over the Landsat MSS system? Describe how the RBV
camera system on Landsats 1 and 2 are different from that
used in Landsat 3.
- Landsat's Thematic Mapper (TM) represents an upgraded MSS
image. How is it better? The TM scan acquires data in
both directions, whereas MSS scans were acquired in only
one direction. How did this affect image acquisition?
- What are the objectives of Landsat 7?
- Describe SPOT's off-nadir viewing system. What are the
advantages? Describe the two modes in which SPOT's HRV
capture data. What are the advantages of the repeat capability of
the SPOT satellite system?
- What is the difference in ground resolution between
Landsat MSS, Landsat TM, SPOT multispectral mode and SPOT
panchromatic mode? Describe the difference in scanning
between the Landsat satellites and SPOT satellites.
- What is a sun-synchronous orbit and why is it important
for land resource mapping? What is a geostationary orbit
and when is this type of orbit used?
- What causes radar shadow? What is radar layover? What is
radar foreshortening? What is polarization and how is it
important in remote sensing? What are the causes of
depolarization? Why is look direction important in radar
remote sensing?
- Describe the basic principles of synthetic aperture
radar.
- A lidar system has been defined as consisting of 4 components.
What are they and for what purpose is each employed within a lidar system?
- What is the difference between a low frequency and high
frequency convolution filter? What is the purpose of the
edge enhancement filter?
- What is skew distortion? How do we deskew an image?
- In our discussion on resampling, three different schemes
were presented. Identify and describe the difference
between two of them.
- Bit errors are a random noise problem in digital data.
Describe how one corrects for these errors. Use a sketch
along with your written response.
- What is the advantage or purpose of spectral ratioing?
- Explain how the histogram is used in destriping.
- Given the following band reflectance values: 180, 215,
205, 200, 235, 205, 195, 185, 206, compute the: a) mode;
b) median; c) arithmetic mean; d) range; e) standard
deviation
- What is a color lookup table?
- What is the value of the color lookup table to the image
analyst?
- Identify and describe two of the advantages of
multispectral scanner data over photography.
- What is a sampling error?
- What does a histogram of remotely sensed data showing
data compression to the lower 1/4 of the range suggest?
Explain your answer.
- Give an example of line drop-out. How is it corrected?
- What is striping or banding and when does it occur?
Describe one method of destriping.
- A correlation coefficient between Band 1 and Band 2 of a
hypothetical remotely sensed data is 0.95. What does this
suggest to the image analyst.
- Discuss three of the considerations that should be raised
when looking at the radiometric correction of
topographically induced effects.
- Creating color composites by using the red, green and
blue (RGB) display memory planes is useful to the analyst
because they can view the different band combinations.
How does the analyst pick which band combination to use
when Landsat TM has six bands?
- Atmospheric correction attempts to minimize or remove the
contribution of path radiance. What is the consistency of
path radiance?
- One of the radiometric corrections is the sun elevation
correction. Why is it employed and how is it determined?
- Identify three design criteria used in the development of
the USGS land use/land cover classification system.
- Describe the specifications used in compiling the current
use inventory within the Michigan Resource Inventory
Program
- Describe the results of tangential scale distortion.
- What are mixed pixels?
- What is the difference between spectral pattern
recognition and spatial pattern recognition methods of
classification? Describe the difference between spectral
classes and informational classes.
- Describe the difference between supervised and
unsupervised classification. Describe the
disadvantages/limitations of unsupervised classification.
Describe unsupervised classification using the chain
method. Describe the 3 basic steps in a typical
supervised classification.
- Describe the parallelepiped classifier. What is the main
difficulty encountered with the parallelepiped
classifier? What is the cause? Describe the concept of a
minimum-distance-to-mean classifier and give an example.
- Given an error matrix, determine the overall accuracy,
producer's accuracy, user's accuracy, and the kappa
coefficient.
- Give an example of how haze compensation can be performed
on MSS data.
- Given a kernel and original DN values, compute a
convoluted image DN value.
- Given DNs from four channels of AVHRR data, compute the
simple vegetation index (VI) and normalized difference
vegetation index (NDVI).
- A data set had the following DN statistics: Mean = 78,
Minimum = 37, Maximum = 137. If the data output
categories are 8 bits (0-255), what are the DN values (in
integers) of some given data after performing a linear
stretch?
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This page is maintained by Bob Burtch and
was last updated on 1 November 2006.
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