Computer Vision

Faster R-CNN replaces Selective Search with which component?

• RPN (Region Proposal Network)
• RoI Align
• Feature Pyramid Network
• Focal Loss head

YOLO v1 default output tensor for PASCAL VOC is:

• 7 × 7 × 20
• 13 × 13 × 25
• 7 × 7 × 30
• 14 × 14 × 30

λ_coord and λ_noobj in YOLO loss are typically:

• 1 and 1
• 5 and 0.5
• 0.5 and 5
• 10 and 0.1

Mask R-CNN's mask head produces:

• A single binary mask per RoI
• K binary masks per RoI (one per class)
• A single multi-class softmax mask per RoI
• Bounding boxes only

Dilated/atrous convolutions enlarge the receptive field by:

• Adding more parameters
• Inserting gaps between kernel taps
• Increasing stride
• Pooling

OpenPose's output channels for K keypoints and L limb types is:

• K + L
• 2K + L
• K + 2L
• 2K + 2L

SMPL's pose parameter θ has dimensionality:

• 10
• 24
• 72
• 6890

PointNet achieves permutation invariance via:

• Sorting input points
• Shared MLP + max-pool
• Voxelization
• Graph convolution

Total learnable parameters per 3DGS Gaussian (degree-3 SH):

• 48
• 59
• 62
• 72

Σ = R·S·Sᵀ·Rᵀ in 3DGS guarantees:

• Diagonal covariance
• Positive semi-definiteness
• Unit determinant
• Orthogonality

Why is QKᵀ divided by √dₖ?

• Numerical stability for softmax to keep gradients alive
• To make the output unit-norm
• To allow positional encoding
• To enforce attention to sum to 1

ViT-B/16 on 224² images yields how many tokens entering the encoder (including [CLS])?

• 196
• 197
• 256
• 224

Which SSL method does NOT use negatives?

• SimCLR
• MoCo
• BYOL
• CLIP

MAE's mask ratio is:

• 15%
• 50%
• 75%
• 90%

RoPE's key property is:

• Adds learnable parameters
• Encodes absolute position
• Dot product depends only on relative position
• Replaces softmax

In PaliGemma, which component is randomly initialised?

• SigLIP encoder
• Gemma decoder
• The linear connector
• All of the above

I3D's 'inflation' trick:

• Trains a 3D CNN from random init
• Replicates 2D pretrained kernels along time, divides by K_T
• Applies 2D conv per frame and pools
• Uses transposed conv