Lesson 4

Question 1

What is morphological image processing?

Answer 1

A tool for extracting image components used to represent the region shape (e.g. boundaries)

Based on mathematical morphology

Question 2

What are morphological operations based on?

Answer 2

Set theory and logic operations

Question 3

Define a structuring element (SE).

Answer 3

A small shape or set to probe the image under study, adapted to geometric properties of objects

Question 4

What does binary dilation do?

Answer 4

Grows (thickens) objects in a binary image

Question 5

What is the effect of binary erosion on an image?

Answer 5

Erodes away the boundaries of regions of foreground pixels, shrinking areas and enlarging holes

Question 6

What is the convolution theorem in image processing?

Answer 6

Convolution in an image domain is equivalent to simple multiplication in the frequency domain

Question 7

What does the Fourier transform allow in image analysis?

Answer 7

Transforms an image into the frequency domain

Question 8

What is the primary use of the Hough transform in image analysis?

Answer 8

To detect shapes, such as lines and circles, in images

Question 9

Fill in the blank: Morphological operations are used to describe and apply _______ for image analysis.

Answer 9

morphological operations

Question 10

What are the two main types of morphological operations?

Answer 10

Dilation and erosion

Question 11

What does the term ‘set theory operations’ refer to in the context of image processing?

Answer 11

Operations such as union, intersection, and complement that are foundational for morphological operations

Question 12

What is the main purpose of using existing functions and software packages like scikit-image?

Answer 12

To automatically analyze images

Question 13

What is the relationship between dilation and erosion?

Answer 13

Dilation and erosion are duals of each other with respect to set complementation and reflection

Question 14

What is the role of the Fourier transform in filtering images?

Answer 14

Allows for frequency domain manipulation to filter images

Question 15

What is a key outcome of applying binary opening?

Answer 15

An erosion followed by a dilation

Question 16

What does the term ‘magnitude’ refer to in the context of the Fourier transform?

Answer 16

The amplitude of the frequency components in an image

Question 17

What is the difference between convolution and multiplication in image processing?

Answer 17

Convolution is slow to compute, while multiplication is fast

Question 18

What does the term ‘top hat operations’ refer to in image analysis?

Answer 18

A morphological operation that extracts small elements from larger ones

Question 19

What is the significance of the image size (M and N) in the Fourier transform?

Answer 19

They define the dimensions of the image in the frequency domain

Question 20

In morphological image processing, what effect does the structuring element have?

Answer 20

Controls the shape and size of the objects being processed

Question 21

What is the purpose of implementing solutions to real-world image analysis problems?

Answer 21

To improve tasks such as contrast enhancement and object counting

Question 22

True or False: The Fourier transform can only represent spatial domain information.

Answer 22

False

Question 23

What is a practical application of image erosion?

Answer 23

Separates touching objects in an image

Question 24

What is the basis for morphological operations?

Answer 24

Set theory operations

Question 25

What is binary opening?

Answer 25

An erosion followed by a dilation.

Question 26

What is the result of binary opening?

Answer 26

Result of Binary Opening (Erosion + Dilation)

Question 27

What is binary closing?

Answer 27

A dilation followed by an erosion.

Question 28

What is the result of binary closing?

Answer 28

Result of Binary Closing (Dilation + Erosion)

Question 29

What is the application of the opening operation?

Answer 29

Often performed to clear an image of noise whilst retaining the original object size.

Question 30

What does the closing operation do?

Answer 30

Used to fill holes in a region whilst retaining the original object size.

Question 31

Fill in the blank: The opening operation tends to ______ the sharp peninsular projections on the object.

Answer 31

flatten

Question 32

What is a structuring element in morphological operations?

Answer 32

A shape used to probe and transform the input image.

Question 33

How does the opening operation affect small bright spots?

Answer 33

It can remove small bright spots (i.e., 'salt').

Question 34

What happens during a dilation operation?

Answer 34

The size of the object in the image increases.

Question 35

What happens during an erosion operation?

Answer 35

The size of the object in the image decreases.

Question 36

What is the purpose of grayscale morphology?

Answer 36

To extend binary morphological operations to grayscale images using min and max operations.

Question 37

True or False: The closing operation can connect small light cracks.

Answer 37

True

Question 38

What is the result of applying grayscale dilation?

Answer 38

The white boundary of the image thickens.

Question 39

What occurs during the closing operation on grayscale images?

Answer 39

Ellipses at the bottom get connected because of dilation.

Question 40

Fill in the blank: The elementary binary morphological operations can be extended to grayscale images through the use of ______ and ______ operations.

Answer 40

min, max

Question 41

What does a hit-and-miss structuring element involve?

Answer 41

It has pixels of 3 values: 0, 1, and 'don't care'.

Question 42

What is a basic morphological smoothing operation?

Answer 42

An opening followed by a closing operation.

Question 43

What is the white top-hat transformation?

Answer 43

Original image minus its opening.

Question 44

What does the black top-hat transformation return?

Answer 44

Returns the dark spots of the image that are smaller than the structuring element.

Question 45

What is the primary goal of morphological operations?

Answer 45

To process images based on their shapes.

Question 46

Fill in the blank: The closing operation tends to fill the ‘______’ on the edge of a region.

Answer 46

bays

Question 47

What is the purpose of the closing operation in image processing?

Answer 47

It removes both bright and dark artifacts of noise.

Question 48

What does the White Top-hat transformation return?

Answer 48

The bright spots of the image that are smaller than the structuring element.

Question 49

What does the Black Top-hat transformation return?

Answer 49

The dark spots of the image that are smaller than the structuring element.

Question 50

What is one of the principal applications of the White and Black Top-hat transformations?

Answer 50

Removing objects from an image using a structuring element.

Question 51

Fill in the blank: The White Top-hat transformation is calculated as the original image minus its _______.

Answer 51

opening

Question 52

Fill in the blank: The Black Top-hat transformation is calculated as the closing minus the _______.

Answer 52

original image

Question 53

What does the function skimage.morphology.label do?

Answer 53

It labels connected components in a binary image.

Question 54

True or False: Two pixels are considered connected if they share a common vertex.

Answer 54

True

Question 55

What are the two types of connectivity mentioned in connected components?

Answer 55

* 4 connectivity * 8 connectivity

Question 56

What does thinning do in image processing?

Answer 56

It removes selected foreground pixels.

Question 57

What is the result of the thinning operation?

Answer 57

It reduces the foreground regions in a binary image to a skeleton.

Question 58

What is the skeleton in the context of image processing?

Answer 58

It is the loci of centers of bi-tangent circles that fit entirely within the foreground region.

Question 59

Fill in the blank: The medial axis is the set of all points having more than one _______ on the object’s boundary.

Answer 59

closest point

Question 60

What does the function medial_axis return in addition to the medial axis?

Answer 60

The distance transform.

Question 61

True or False: Skeletonization retains the size of the input object.

Answer 61

True

Question 62

What is the main difference between thinning and skeletonization?

Answer 62

Thinning reduces the object to a 1-pixel wide representation, while skeletonization retains the size.

Question 63

What is the purpose of the structuring element in morphological operations?

Answer 63

It defines the neighborhood used to process the image.

Question 64

Fill in the blank: The structuring element has pixels of 3 values: 0, 1, and _______.

Answer 64

Don’t care

Question 65

What is the effect of a structuring element with a value of 1?

Answer 65

The corresponding pixel must be 1.

Question 66

What is the effect of a structuring element with a value of 0?

Answer 66

The corresponding pixel must be 0.