
Deep Learning for Computer Vision Quiz 2: 16 March 2025 (January 2025 term)
The IIT Madras BS Deep Learning for Computer Vision (Deep Learning for Computer Vision) Quiz 2 paper sat on 16 Mar 2025, in the January 2025 term: 37 questions for 65 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.
- 37
- 65
- 120 min
- 16
- 3
- 18
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Correct answer
Question 2
Which one of the following object detection networks uses an ROI pooling layer?
Fast R-CNN
R-CNN
YOLO
All of these
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Correct answer
Fast R-CNN
Question 3
Match the following:
| 1) VGGNet | i) convolution |
|---|---|
| 2) EfficientNet | ii) identity mapping |
| 3) GoogleNet | iii) convolution |
| 4) ResNet | iv) convolution |
| v) depth-wise separable convolutions |
1→iv, 2→ii, 3→v, 4→i
1→iv, 2→iii, 3→v, 4→ii
1→iv, 2→v, 3→ii, 4→iii
1→iii, 2→v, 3→i, 4→ii
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Correct answer
1→iii, 2→v, 3→i, 4→ii
Question 4
Which one of the following statements is False?
In a max pooling layer, the unit that gets selected (maximum entry) in forward propagation gets all the gradient during backpropagation.
Residual blocks are used in ResNets to avoid the vanishing gradient problem.
Feature maps of initial layers of a CNN capture more abstract concepts than the feature maps of final layers.
Dilated convolution increases the receptive field size when compared to the standard convolution operator.
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Correct answer
Feature maps of initial layers of a CNN capture more abstract concepts than the feature maps of final layers.
Question 5
Sigmoid of alignment scores
Softmax of alignment scores
ReLU of alignment scores
None of these
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Correct answer
Softmax of alignment scores
Question 6
In object detection using CNNs, which loss function is typically used to optimize the confidence scores assigned to predicted bounding boxes, aiming to ensure high confidence for correct detec- tions and penalize false positives?
Focal Loss
Smooth Ll Loss
Binary Cross-Entropy Loss
Mean Squared Error (MSE)
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Correct answer
Binary Cross-Entropy Loss
Question 7
Consider two 12 × 12 bounding boxes(one on the upper left and one of the lower right) in an images with an overlapping region of 8 × 8. The Intersection over Union (IoU) between the two boxes is (choose the closest value):
21%
25%
28%
37%
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Correct answer
28%
Question 8
In object detection using CNNs, what is the challenge addressed by the non-maximum suppression (NMS) technique?
Handling variations in object scale and aspect ratio
Improving the localization accuracy of detected objects
Reducing the computational complexity of the detection process
Removing redundant bounding box predictions for the same object
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Correct answer
Removing redundant bounding box predictions for the same object
Question 9
Match the following computer vision tasks to situations:
| 1) Instance Segmentation | i) There are cars in these pixels |
|---|---|
| 2) Classification | ii) There are 4 cars in the image |
| 3) Semantic Segmentation | iii) There is car in the image |
| 4) Object Detection | iv) There are 4 cars in the image, and here are the pixels with the shape of each of their occurrence |
1→ iv, 2→ iii, 3→ ii, 4 → i
1→ ii, 2→ iii, 3 → i, 4 →iv
1→ iv, 2→ iii, 3→ i, 4 → ii
1→ ii, 2→ iv, 3 → iii, 4→ i
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Correct answer
1→ iv, 2→ iii, 3→ i, 4 → ii
Question 10
Match the following:
| 1) One-to-many RNN architecture | i) Sentiment analysis of Netflix reviews |
|---|---|
| 2) Many-to-one RNN architecture | ii) Convert English sentence to Hindi |
| 3) Many-to-many RNN architecture with equal number of inputs and outputs | iii) Named entity recognition |
| 4) Many-to-many RNN architecture with unequal number of inputs and outputs (Encoder and Decoder model) | iv) Music generation |
1→ iii, 2→ iv, 3→ ii, 4 → i
1→ iv, 2→ i, 3 → iii, 4→ ii
1→ i, 2→ ii, 3 → iii, 4→ iv
1→ i, 2→ iii, 3 → ii, 4→ iv
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Correct answer
1→ iv, 2→ i, 3 → iii, 4→ ii
Question 11
Match the following attention mechanisms to their corresponding alignment score functions:
| (1) General Attention | (i) |
|---|---|
| (2) Content-Based Attention | (ii) |
| (3) Dot-Product Attention | (iii) |
| (4) Additive Attention | (iv) |
| (5) Location-Based Attention | (v) |
1→iii, 2→ii, 3→v, 4→iv,5→i
1→iii, 2→iv, 3→i, 4→ii,5→v
1→i, 2→iii, 3→iv, 4→ii,5→v
1→v, 2→iv, 3→iii, 4→i,5→ii
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Correct answer
1→v, 2→iv, 3→iii, 4→i,5→ii
Question 12
Which of the following techniques help control the exploding or vanishing gradient problem in recurrent neural networks?
1. Gradient clipping
2. Use ReLU activation funtion to control exploding gradient and sigmoid activation to control vanishing gradients
3. Use Long Short-Term Memory (LSTM)
4. Use data augmentation methods (for example, reversing the input sequence)
1, 2, and 3; but not 4
1, 3, and 4; but not 2
All of these
Only 1 and 3
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Correct answer
1, 3, and 4; but not 2
Question 13
State whether the given statement is True or False:
While training an object detection algorithm, you need a training set that contains many pictures of the objects you want to detect. However, bounding boxes are not typically provided in the training set, since architectures like Faster-RCNN and YOLO can learn to detect the object by themselves.
True
False
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Correct answer
False
Question 14
How are saliency maps generated in the context of Convolutional Neural Networks (CNNs)?
By applying a convolutional filter to the input image
By computing the gradient of the model’s output with respect to the input image
By randomly sampling regions of the image and assessing their importance
By measuring the similarity between the input image and pre-trained feature maps
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Correct answer
By computing the gradient of the model’s output with respect to the input image
Question 15
Consider an object detection system evaluated on a dataset consisting of 1000 images. The system makes 1500 predictions across these images, and for each image, there are annotated ground truth bounding boxes.
The system’s precision-recall curve is calculated, and the precision at different recall levels for one of the classes is as follows:
| Recall | Precision |
|---|---|
| 0.1 | 0.90 |
| 0.2 | 0.85 |
| 0.3 | 0.80 |
| 0.4 | 0.75 |
| 0.5 | 0.70 |
| 0.6 | 0.65 |
| 0.7 | 0.60 |
| 0.8 | 0.55 |
| 0.9 | 0.50 |
| 1.0 | 0.45 |
Calculate the mean Average Precision (mAP) for this class using the 11-point interpolation method, which averages the precision values at recall levels {0.0, 0.1, 0.2, ..., 1.0}. The precision at recall 0.0 can be assumed to be 1.0.
Additionally, the system’s AP values for the other two classes are as follows:
- AP for class 2: 0.78
- AP for class 3: 0.72
Based on these AP values, what is the mean Average Precision (mAP) across all three classes?
0.70
0.69
0.73
0.76
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Correct answer
0.73
Question 16
Which one of the following statements is false? (Pick the most appropriate one.)
Attention mechanisms cannot be applied to the bidirectional RNN model
An image captioning network cannot be trained end-to-end even though we are using 2 different modalities to train the network
One of the key components in the vanilla transformer is the recurrent connection that help them to deal with variable input length.
All of these
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Correct answer
All of these
Question 17
Which of the following statements is True (select all that apply):
The number of learnable parameters in an RNN grows exponentially with input sequence length considered
Long sentences give rise to the vanishing gradient problem
Electrocardiogram signal classification is a sequence learning problem
RNNs can have more than one hidden layer
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Correct answers
Long sentences give rise to the vanishing gradient problem
Electrocardiogram signal classification is a sequence learning problem
RNNs can have more than one hidden layer
Question 18
Which of the following is true regarding Hard Attention and Soft Attention?
Soft Attention is smooth and differentiable
Variance reduction techniques are used to train Soft Attention models
Soft Attention is computationally cheaper than Hard Attention when the source input is large
The inference (test time) overhead is low in Hard Attention when compared to Soft Attention models
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Soft Attention is smooth and differentiable
The inference (test time) overhead is low in Hard Attention when compared to Soft Attention models
Question 19
Which of the following are true?
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Question 20
Consider a Faster R-CNN object detection framework, which is being trained with a minibatch size of 2. The RPN produces 512 proposals, out of which 256 and 128 of them are foreground proposals, corresponding to each image in the mini-batch. For a single mini-batch update, the bounding box regression loss will be computed _______________ times.
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Correct answer: 384
Question 21
Based on the above data, answer the given subquestions.
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Correct answer: 4
Question 22
Based on the above data, answer the given subquestions.
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Correct answer: 6
Question 23
Based on the above data, answer the given subquestions.
Show answer
Correct answer: 3
Question 24
Based on the above data, answer the given subquestions.
Show answer
Correct answer: 1
Question 25
Based on the above data, answer the given subquestions.
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Correct answer: 2
Question 26
Based on the above data, answer the given subquestions.
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Correct answer: 5
Question 27
Based on the above data, answer the given subquestions.
Number of Parameters: __________________
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Correct answer: 12800
Question 28
Based on the above data, answer the given subquestions.
Computational Cost: __________________
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Correct answer: 209715200
Question 29
Let input have size where and and output feature map (after passing input through conv layer) has size where . Assume padded convolution. Let width of the square kernel in conv layer be where (Ignore the bias term in the calculation).
Calculate the number of parameters and computational cost, but make use of Depthwise Seperable convolution and pointwise convolution instead of standard convolution.
Based on the above data, answer the given subquestions.
Number of parameters for depthwise convolution: __________________
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Correct answer: 400
Question 30
Let input have size where and and output feature map (after passing input through conv layer) has size where . Assume padded convolution. Let width of the square kernel in conv layer be where (Ignore the bias term in the calculation).
Calculate the number of parameters and computational cost, but make use of Depthwise Seperable convolution and pointwise convolution instead of standard convolution.
Based on the above data, answer the given subquestions.
Computational Cost for depthwise convolution: ________________
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Correct answer: 6553600
Question 31
Let input have size where and and output feature map (after passing input through conv layer) has size where . Assume padded convolution. Let width of the square kernel in conv layer be where (Ignore the bias term in the calculation).
Calculate the number of parameters and computational cost, but make use of Depthwise Seperable convolution and pointwise convolution instead of standard convolution.
Based on the above data, answer the given subquestions.
Number of parameters for pointwise convolution: _________________
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Correct answer: 512
Question 32
Let input have size where and and output feature map (after passing input through conv layer) has size where . Assume padded convolution. Let width of the square kernel in conv layer be where (Ignore the bias term in the calculation).
Calculate the number of parameters and computational cost, but make use of Depthwise Seperable convolution and pointwise convolution instead of standard convolution.
Based on the above data, answer the given subquestions.
Computational cost for pointwise convolution: ___________________
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Correct answer: 8388608
Question 33
Based on the above data, answer the given subquestions.
Number of weights in Weight Matrix U1 is: ______________
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Correct answer: 5000
Question 34
Based on the above data, answer the given subquestions.
Number of weights in Weight Matrix V1 is: _______________
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Correct answer: 2500
Question 35
Based on the above data, answer the given subquestions.
Number of weights in Weight Matrix U2 is: ________________
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Correct answer: 10000
Question 36
Based on the above data, answer the given subquestions.
Number of weights in Weight Matrix V2 is: ______________
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Correct answer: 40000
Question 37
Based on the above data, answer the given subquestions.
Number of weights in Weight Matrix W is: ________________
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Correct answer: 200000