GGR 315 Environmental Remote Sensing, 2024
Assignment 5: Image Classification and color display
Questions
(100 marks, 10% of the final grade)
1. (20 marks) The following are the training field spectral statistics for three forest types:
Forest type
|
mean spectral value
|
standard deviation
|
Black spruce
|
25
|
8
|
Paper birch
|
45
|
12
|
Quaking aspen
|
65
|
12
|
Show the likelihood curves for these three cover types and classify the following image using the maximum likelihood rule. In the classified image use the following code: BS for black spruce; PB for paper birch; and QA for quaking aspen. (5 marks for each line; 5 marks for classification results)
Original image
Classified image
2. (20 marks, 5 for each) From the confusion matrix shown below,
a. Calculate the producer’s accuracy for Type 2;
b. Calculate the user’s accuracy for Type 1;
c. Calculate the overall accuracy and the KHAT value of this classification (show intermediate calculations);
d. Explain why KHAT better represents the classification accuracy than the overall accuracy.
Classified Cover Type
|
Ground Truth Cover Type
|
Type 1
|
Type 2
|
Type 3
|
Type 4
|
Row Totals
|
Type 1
|
25
|
0
|
0
|
3
|
28
|
Type 2
|
0
|
20
|
10
|
0
|
30
|
Type 3
|
5
|
3
|
17
|
0
|
25
|
Type 4
|
2
|
0
|
0
|
40
|
42
|
Column Totals
|
32
|
23
|
27
|
43
|
125
|
3. (20 marks) Image classification. Following Lab 5 exercise, produce classified images using unsupervised and supervised methods with the following classes: vegetation, water and built area (bare soil). Attach final land cover maps in color in screenshots. (10 marks for each)
4. (20 marks) Explain the main difference and similarity between supervised and unsupervised classification. (5 marks) Provide an error matrix for the supervised classification of the image in Lab 5. (10 marks) Discuss the accuracy assessment on the supervised classification. (5 marks)
5. (10 marks) Explain the following color display techniques: (a) true color, (b) false color, (c) greyscale and (d) pseudo color.
6. (10 marks) What are the three additive primaries? (2 marks) In a 6-bit display device, fill in the blank spaces in the three display channels (red, green, and blue) in the following table with digital numbers that produce the colors specified in the last column with the highest intensities. (8 marks)
Pixel
|
Red
|
Green
|
Blue
|
Apparent Color
|
1
|
|
|
|
red
|
2
|
|
|
|
green
|
3
|
|
|
|
blue
|
4
|
|
|
|
yellow
|
5
|
|
|
|
white
|
6
|
|
|
|
black
|