1. What does the perimeter of a shape represent in digital image processing?
(A) Number of pixels inside the shape
(B) Average pixel intensity
(C) Boundary length of the shape
(D) Diameter of the shape
2. Which shape descriptor measures the space enclosed by a shape?
(A) Perimeter
(B) Compactness
(C) Area
(D) Eccentricity
3. What is the formula for compactness in shape analysis?
(A) Area / Perimeter
(B) (Perimeter²) / Area
(C) Perimeter / Area²
(D) (Area²) / Perimeter
4. What does a compactness value closer to 1 indicate?
(A) Shape is irregular
(B) Shape is rectangular
(C) Shape is circular
(D) Shape is elongated
5. Which of the following best defines eccentricity in shape descriptors?
(A) Ratio of perimeter to area
(B) Ratio of minor to major axis
(C) Ratio of major to minor axis
(D) Product of perimeter and area
6. What does high eccentricity imply about a shape?
(A) It is close to a circle
(B) It is highly compact
(C) It is elongated
(D) It has small area
7. Which shape has the lowest compactness value among the following?
(A) Circle
(B) Rectangle
(C) Triangle
(D) Irregular blob
8. Which descriptor can help differentiate between a circle and an ellipse?
(A) Area
(B) Perimeter
(C) Eccentricity
(D) Compactness
9. What is the compactness of a perfect circle?
(A) π
(B) 1
(C) 4π
(D) 0
10. Which feature is most useful for distinguishing between elongated and round shapes?
(A) Area
(B) Perimeter
(C) Compactness
(D) Eccentricity
11. What does an eccentricity value of 1 indicate in an ellipse?
(A) It is a perfect ellipse
(B) It is a line
(C) It is a circle
(D) It is square
12. How is area calculated in a digital binary image?
(A) Number of white pixels in the object
(B) Number of pixels on the border
(C) Sum of gray levels
(D) Difference between width and height
13. Which descriptor is least affected by rotation of the object?
(A) Area
(B) Perimeter
(C) Compactness
(D) Eccentricity
14. Which of the following is not a shape descriptor?
(A) Perimeter
(B) Histogram Equalization
(C) Area
(D) Eccentricity
15. What is the unit of area in a binary image?
(A) cm²
(B) Number of pixels
(C) mm²
(D) Inches
16. If an object has a very high compactness value, what does it suggest?
(A) The shape is nearly circular
(B) The shape is large
(C) The shape is very irregular
(D) The shape is square
17. Which descriptor is scale-invariant under uniform scaling?
(A) Perimeter
(B) Area
(C) Compactness
(D) Diameter
18. In digital image processing, what is often used to normalize shape descriptors?
(A) Color
(B) Intensity
(C) Bounding box
(D) Scale factor
19. Which feature varies with zoom level in an image?
(A) Eccentricity
(B) Area
(C) Compactness
(D) Shape
20. How does rotation affect eccentricity of a shape?
(A) Increases
(B) Decreases
(C) Remains constant
(D) Becomes zero
21. Which of the following helps in detecting circularity of a region?
(A) Eccentricity
(B) Compactness
(C) Area
(D) Histogram
22. Which feature describes how stretched a shape is?
(A) Area
(B) Eccentricity
(C) Perimeter
(D) Solidity
23. Which of the following will change if the image is scaled up?
(A) Eccentricity
(B) Compactness
(C) Area
(D) Shape
24. A shape with high compactness and low eccentricity is likely to be:
(A) Square
(B) Elliptical
(C) Circular
(D) Irregular
25. In a perfect ellipse, how is eccentricity defined?
(A) 0
(B) Between 0 and 1
(C) Greater than 1
(D) Exactly 1
26. Which of the following is most useful in measuring the overall irregularity of an object?
(A) Perimeter
(B) Area
(C) Compactness
(D) Width
27. If two objects have the same area but different perimeters, which descriptor best highlights the difference?
(A) Eccentricity
(B) Compactness
(C) Diameter
(D) Bounding box
28. What is the effect of noise on perimeter calculation?
(A) No effect
(B) Reduces it
(C) Increases it
(D) Makes it zero
29. Which shape descriptor can help detect elongated structures in medical imaging?
(A) Area
(B) Compactness
(C) Eccentricity
(D) Diameter
30. The ratio of area to bounding box area is called:
(A) Compactness
(B) Solidity
(C) Eccentricity
(D) Circularity
31. Which descriptor remains unchanged after image rotation?
(A) Perimeter
(B) Area
(C) Eccentricity
(D) All of the above
32. What does perimeter measure in a binary image?
(A) Intensity
(B) Thickness
(C) Boundary length
(D) Shape depth
33. Which descriptor best differentiates a star shape from a circle of equal area?
(A) Area
(B) Compactness
(C) Perimeter
(D) Eccentricity
34. Which feature becomes unstable for very small shapes?
(A) Area
(B) Perimeter
(C) Eccentricity
(D) Compactness
35. Which descriptor is most robust to small boundary fluctuations?
(A) Eccentricity
(B) Compactness
(C) Area
(D) Perimeter
36. Compactness is a dimensionless quantity because:
(A) It is always an integer
(B) Units cancel out
(C) It is zero
(D) It is a ratio of lengths
37. Which of the following describes the distribution of mass in a shape?
(A) Eccentricity
(B) Centroid
(C) Compactness
(D) Solidity
38. How is a circularity measure different from compactness?
(A) It is not scale-invariant
(B) It uses diameter
(C) It is normalized to 1 for circles
(D) It cannot be calculated for irregular shapes
39. What is the value of eccentricity for a perfect circle?
(A) 0
(B) 0.5
(C) 1
(D) Infinite
40. Which of the following is a global shape descriptor?
(A) Eccentricity
(B) Texture
(C) Gradient
(D) Edge map
41. Which shape descriptor is used in Fourier descriptors as normalization factor?
(A) Area
(B) Perimeter
(C) Compactness
(D) Eccentricity
42. The centroid of a shape is its:
(A) Topmost point
(B) Center of mass
(C) Longest edge
(D) Diameter
43. In binary shape analysis, the perimeter is typically calculated using:
(A) Area counting
(B) Run length coding
(C) Border tracing
(D) Thresholding
44. How can one reduce the impact of noise on perimeter calculation?
(A) Use a smaller image
(B) Increase contrast
(C) Apply smoothing
(D) Count pixels twice
45. A rectangle has higher eccentricity than:
(A) Line
(B) Circle
(C) Ellipse
(D) Triangle
46. Which of the following is not a rotationally invariant shape descriptor?
(A) Area
(B) Perimeter
(C) Major Axis
(D) Compactness
47. Which descriptor helps in estimating object elongation?
(A) Area
(B) Solidity
(C) Eccentricity
(D) Orientation
48. Solidity equals 1 for which shape?
(A) Donut
(B) Square
(C) Convex shape
(D) Concave shape
49. Which descriptor is most affected by jagged edges?
(A) Compactness
(B) Eccentricity
(C) Area
(D) Solidity
50. Which of the following pairs best differentiates circular and elongated shapes?
(A) Area and Solidity
(B) Eccentricity and Compactness
(C) Perimeter and Orientation
(D) Diameter and Convex Hull
