Question 1
Consider the following numpy array
Now consider the following operations
Write the value of arr[2]

The IIT Madras BS Deep Learning for Computer Vision (Deep Learning for Computer Vision) Quiz 1 paper sat on 23 Feb 2025, in the January 2025 term: 36 questions for 60 marks in 120 minutes. Every question is below with its answer. Take it as a timed mock test to be marked, or read it through first.
Consider the following numpy array
Now consider the following operations
Write the value of arr[2]
Correct answer: 2
Consider the following numpy array
Now consider the following operations
Write the value of arr[2]
Correct answer: 20
Consider the grayscale image shown below:
If a median filter with a neighborhood is applied to this image with a stride of 1 and no padding, __________ will be the value at position in the filtered image? (Assume that the top-left pixel coordinate of output image is addressed as )?
Correct answer: 30
Correct answer: -0.335 (accepted within ±0.005)
What is the size of the feature map after applying two successive convolution operations with given parameters? Image size = 64 x 64, Kernel size = 3 x 3, Padding = 2 and Stride = 3. (In calculation, take floor(x) whenever x is non-integer. If the answer is FxF, write F in the blank).
Correct answer: 8
Let an input to a convolutional layer in a CNN have size Df × Df × M where Df = 32 and M = 100, and output feature map (after passing input through conv layer) has Df × Df × N size where N = 64. Let the kernel in the conv layer be k × k where k = 5. Calculate the number of parameters for this convolution layer. (Assume appropriate padding is applied for all convolutions so the input and output sizes are equal. Ignore the bias term in the calculation)._________________
Correct answer: 160000
Correct answer: -0.235 (accepted within ±0.025)
Given is a 8-bit grayscale image:
What is the mean of transformed pixels of after applying linear contrast stretching? Linear contrast stretching is an image enhancement technique used to improve the contrast in an image. This is achieved by linearly scaling the pixel values so that they span a desired range (0 to 255 for an 8-bit grayscale image).
119.33
110.5
134.25
0
Correct answer
119.33
Which of the following statements is True ?
Gaussian filter is Separable filter because it is non linear.
Median filter is a non separable filter
Gaussian filter is a High Pass filter.
Mean filter is a non separable filter because it is non linear
Correct answer
Median filter is a non separable filter
0.18, 1.5, 1.5, 0.20,−1.5,−0.015
0.92, 2.5, 1, 2.5, 2.5, 1
0.18,−1.5, 0, 0.20, 0,−0.015
0.91, 1, 0, 0.2, 1, 1.7
Correct answer
0.18,−1.5, 0, 0.20, 0,−0.015
Identify the correct sequence of steps in a Canny edge detection pipeline. Steps are listed below: 1. Compute gradient magnitude and direction
2. Connect individual components
3. Smoothen the image
4. Threshold into strong, weak, or no edge
5. Gaussian Filter and Hysteresis
6. Non-maximum suppression
7. Apply derivative to get edges
6→ 1→ 4→ 5 → 2
3→ 1→ 6→ 4 → 2
3→ 5→ 1→ 4 → 2
6→ 1→ 5→ 7 → 2
Correct answer
3→ 1→ 6→ 4 → 2
Identify the correct sequence of steps in Scale Invariant Feature Transform (SIFT) method. Steps listed below:
1. Keypoint Descriptor
2. Keypoint Localization
3. Scale-space Extrema Detection
4. Orientation Estimation
4→ 2→ 1→ 3
3→ 2→ 4→ 1
3→ 1→ 2→ 4
None of these.
Correct answer
3→ 2→ 4→ 1
1→ iii, 2→ i, 3 → ii
1→ iii, 2→ ii, 3 → i
1→ ii, 2→ iii, 3 → ii
None of these
Correct answer
1→ iii, 2→ i, 3 → ii
Suppose we have a codebook of 2048 SIFT visual words. We extract 1000 SIFT descriptors (SIFT is a 128-dimensional feature) from a new image. What is the dimensionality of the BoW (Bag-of-Words) descriptor?
1000
128
128 × 2048
2048
Correct answer
2048
Match the derivative of activation functions with their counterparts on the right column accordingly.
| 1) Leaky ReLU | i) |
|---|---|
| 2) Tanh | ii) 0 if and 1 if |
| 3) ReLU | iii) |
| 4) Sigmoid | iv) 0.01 if and 1 if |
| v) 0 if and 1 if | |
| vi) 0.01 if and 1 if |
1→ vi, 2→ iii, 3→ v, 4 → i
1→ i, 2→ iv, 3 → iii, 4→ ii
1→ i, 2→ v, 3 → iii, 4→ iv
1→ iv, 2→ iii, 3→ ii, 4 → i
Correct answer
1→ iv, 2→ iii, 3→ ii, 4 → i
Consider a Convolutional Neural Network which processes an RGB image. It has 128 kernels each of spatial dimension 5 × 5 in the first layer. They are convolved with a stride 1. This is followed by a max-pooling layer with stride 2 and kernel size 5 × 5. What would be the receptive field size of a single neuron in the pooling layer? (Recap: A receptive field is the size of the region in the input image, which influences the activation of that specific neuron.)
5 × 5
7 × 7
9 × 9
3 × 3
Correct answer
9 × 9
Consider the following two statements. Which of the following statements are true?
(a) Convolution operator is both commutative and associative.
(b) Fourier transform of a convolved image FT (a * b), is not the product of the Fourier transform of the constituent images FT(a) x FT(b)
a and b
not a but b
a but not b
Neither a nor b
Correct answer
a but not b
A 3x3 kernel generates an output image of dimension 20x20 after convolution. The (approximate) number of computations performed to obtain this output image is:
3600
180
400
9
Correct answer
3600
Which of the following statements are True?
Vanilla Gradient Descent converges faster than Momentum-based GD.
Momentum based GD oscillates around minima before convergence.
Noise in Stochastic Gradient descent weight updates – can lead to faster convergence.
None of these
Correct answer
Momentum based GD oscillates around minima before convergence.
1→ iii, 2→ iv, 3→ i, 4 → ii
1→ iii, 2→ i, 3 → ii, 4 →v
1→ iii, 2→ iv, 3→ v, 4 → ii
1→ iv, 2→ iii, 3→ i, 4 → ii
Correct answer
1→ iii, 2→ iv, 3→ v, 4 → ii
Which of the following statements is false?
Linear contrast stretching is a local operation.
Moving average is an example of local operation.
Convolution in the spatial domain can be obtained through addition in the frequency domain.
All of these.
Correct answers
Linear contrast stretching is a local operation.
Convolution in the spatial domain can be obtained through addition in the frequency domain.
Which of the following statements are false?
Momentum in optimization can cause oscillations around minima when encountering flat regions or saddle points due to the dominance of the momentum term over the small gradient.
Stochastic Gradient Descent (SGD) with its inherent noise can be beneficial in escaping local minima and saddle points, provided that there is enough gradient information in the neighborhood.
Adagrad is an optimization algorithm introduced to overcome the diminishing learning rate problem in techniques like RMSProp.
ADAM is introduced to solve problems in RMSProp by combining RMSProp and Adagrad techniques.
Correct answers
Adagrad is an optimization algorithm introduced to overcome the diminishing learning rate problem in techniques like RMSProp.
ADAM is introduced to solve problems in RMSProp by combining RMSProp and Adagrad techniques.
Correct answer
Certain 2D kernel can be decomposed into two 1D kernels ( and ) to reduce the computation cost such as . The 2D kernel is called as Separable Kernel.
Consider the following 2D kernels
Which of the above kernels are separable?
(a)
(b)
(c)
(d)
Correct answers
(a)
(d)
Which of the following statements are true? (Select all that apply)
Correct answers
Which of the following are true? (Select all that apply)
Correct answers
Based on the above data answer the given subquestions.
Enter the correct answer for blank (a) ____________
NOTE: Enter the exact answer without any extra space in the beginning or at the end.
Correct answer: high
Based on the above data answer the given subquestions.
Enter the correct answer for blank (b) ____________
NOTE: Enter the exact answer without any extra space in the beginning or at the end.
Correct answer: high
Based on the above data answer the given subquestions.
Enter the correct answer for blank (a) ____________
NOTE: Enter the exact answer without any extra space in the beginning or at the end.
Correct answer: thick or coarse or large scale
Based on the above data answer the given subquestions.
Enter the correct answer for blank (b) ____________
NOTE: Enter the exact answer without any extra space in the beginning or at the end.
Correct answer: fine
Based on the above data answer the given subquestions.
a11= ____________
Correct answer: 1
Based on the above data answer the given subquestions.
a12= ____________
Correct answer: 0.5
Based on the above data answer the given subquestions.
a21= ____________
Correct answer: 0
Based on the above data answer the given subquestions.
a22= ____________
Correct answer: 1
Correct answer: 3
Correct answer: 55