Digital Image Processing - Image Processing and Analysis - Geomatics Engineering Previous Year Questions

1

2024 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2024

Hyperspectral sensor consists of

A

large number of wide and discrete bands

B

small number of wide and contiguous bands

C

large number of narrow and contiguous bands

D

small number of narrow and discrete bands

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2

2024 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2024

A one-dimensional normalized kernel \(\frac{1}{4}[1 \quad 2 \quad 1]\) is convolved with an image to produce an intermediate result. The intermediate image of this operation is again convolved with the same kernel to produce a final result. The equivalent kernel to achieve the same final result in one step from the original image is given as

A

\(\frac{1}{16}[1 \quad 4 \quad 6 \quad 4 \quad 1]\)

B

\(\frac{1}{16}[1 \quad 2 \quad 1 \quad 2 \quad 1]\)

C

\(\frac{1}{8}[1 \quad 2 \quad 4 \quad 2 \quad 1]\)

D

\(\frac{1}{10}[1 \quad 2 \quad 4 \quad 2 \quad 1]\)

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3

2024 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2024

For the following covariance matrix (\(\Sigma\)) of a multispectral image, which of the statements is/are INCORRECT? \[ \[\Sigma = \begin{matrix}\] & \text{band-1} & \text{band-2} & \text{band-3} \\ \[\text{band-1} & 34.14 & 46.71 & 40.68 \\\] \[\text{band-2} & 46.71 & 68.83 & 69.59 \\\] \[\text{band-3} & 40.68 & 69.59 & 248.40\] \end{matrix} \]

A

band-1 and band-2 have maximum correlation

B

band-2 and band-3 are least correlated

C

band-3 conveys the maximum information content

D

band-1 conveys the minimum information content

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4

2024 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2024

Which of the following statistical measures CANNOT be computed from the multispectral image histograms?

A

Mean, skewness, kurtosis

B

Covariance matrix

C

Co-occurrence matrix

D

Correlation matrix

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5

2024 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2024

Using the given 3 × 3 pixel kernel and original image and applying the concept of convolution, the value of central pixel of the output image is ______ (in integer).

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6

2025 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2025

Consider the three input raster images given below. A geospatial analyst decided to use the overlay operation to generate a new raster showing the average values. The values of the cells P, Q and R in the output raster are:

A

P = 3, Q = 3, R = 2

B

P = 4, Q = 4, R = 3

C

P = 3, Q = 3, R = 3

D

P = 4, Q = 4, R = 2

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7

2025 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2025

Which one of the following is NOT used to assess the quality of remote sensing image?

A

Univariate statistics of image

B

Histogram

C

Multivariate statistics of image

D

Swath of the image

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8

2025 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2025

Principal Component Analysis is performed on a 4-band IRS satellite image. The eigen values \(E = [\lambda_{1,1}, \lambda_{2,2}, \lambda_{3,3}, \lambda_{4,4}]\) computed from the covariance matrix are 887.60, 75.20, 37.60 and 6.73, respectively. The percentage of total variance explained by the third principal component \(\lambda_{3,3}\) is ______ (rounded off to 2 decimal places).

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9

2025 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2025

The figure below shows a one-dimensional function, \(f\), and a filter \(w\). Consider \(f\) is padded with zeros on both sides. Which one among the following will be the final convolution output of \(f\) with \(w\) after the padding zeros are removed from the output?

A

0 0 1 0 0

B

3 2 1 0 0

C

0 0 1 2 3

D

1 2 3 0 0

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10

2025 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2025

For the correlation matrix of a 4-band satellite image as shown below, which of the following statements is/are correct?

A

Band 3 provides some unique information not found in other bands

B

There is high redundancy in band 2 and 4

C

The standard deviation of all the bands is equal

D

Image cannot be classified using bands 1 and 3 only

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11

2022 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2022

The spatial resolution of a satellite image P is 80 m and another satellite image Q is 20 m; each of 512 × 512 pixel size. Choose the CORRECT option(s).

A

Image P will cover four times the area of image Q.

B

Image P will cover sixteen times the area of image Q.

C

Minor details will be more clear in image Q as compared to image P.

D

Image P is higher resolution and image Q is lower resolution.

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12

2022 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2022

Which statement(s) is/are CORRECT for Hyperspectral images?

A

Bandwidth is large.

B

Bandwidth is narrow.

C

Number of bands are more.

D

Bands are contiguous.

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13

2022 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2022

In a Landsat-8 scene, digital number (DN) values of a pixel in band-4, band-5 and band-10 are 80, 100 and 30, respectively. What would be the NDVI value for the same pixel (round off to 3 decimal places)?

A

0.111

B

0.222

C

0.556

D

0.889

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14

2023 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2023

A GIS analyst has two raster datasets with the same number of rows and columns. The analyst computes the average of the two input raster layers to generate a new raster layer with the same size as the input raster layers. What type of raster data analysis operation is performed?

A

Local

B

Neighborhood

C

Zonal

D

Global

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15

2023 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2023

A child travelling in a bus is staring at the wheels of a car. To the child’s amusement the car wheels appear to spin backwards, but the car moves forward. This perception is because of the nature of our human visual sensory system, and is attributed to ________.

A

aliasing

B

convolution

C

filtering

D

modulation

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16

2023 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2023

Which one of the following is NOT a linear operation?

A

Convolution

B

Moving average

C

Filtering with a median filter

D

Similarity transformation

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17

2023 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2023

In the grid below, the four corners A, B, C and D are the pixel locations on an image. The brightness values at pixels A, B, C and D are 10, 20, 5 and 30, respectively. Using bilinear interpolation, the brightness value determined at point P is __________.(Rounded off to 1 decimal place)

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18

2026 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2026

Which is/are the CORRECT option(s) that indicate(s) a multispectral sensor?

A

A sensor with 10 non-contiguous spectral bands having a bandwidth of about 0.04 μm

B

A sensor with 256 contiguous spectral bands with each having a bandwidth of 5 nm

C

A sensor with a single spectral band having a bandwidth of 0.4 μm

D

A sensor with 1000 contiguous spectral bands with each having a bandwidth of 1 nm

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19

2026 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2026

Consider the following arrangement of pixels P, P₁, P₂, P₃ and P₄ as shown in the figure. Assume that P, P₂ and P₄ have a value of 1, and P₁ and P₃ have a value of 0. If we consider adjacency of pixels as V = {1}, what is the length of the shortest m-path between P and P₄?

A

2

B

1

C

3

D

4

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20

2026 · Geomatics Engineering · Image Processing and Analysis · Digital Image Processing

Geomatics Engineering (GE) 2026

Convolution of two digital images in the spatial domain corresponds to ___________ in the frequency domain.

A

multiplication

B

convolution

C

addition

D

cross-correlation

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