Easy concepts in Computer Vision, page 2
Background Subtraction: Finding What's Moving in Video
Think of a security camera that has memorized the empty room. Background subtraction digitally 'subtracts' this static view from the live feed, leaving only moving objects. It’s used to spot intruders or count cars, but fails if the background itself changes.
Optical Flow: Tracking Motion by Watching Pixels
Optical flow tracks motion by watching how brightness patterns move between video frames. It's used for video compression and robot navigation. The main footgun is that it can mistake lighting changes, like a shadow moving, for actual object motion.
Action Recognition: Teaching Machines to Understand 'Doing'
Action recognition teaches computers to understand *what* is happening in a video by analyzing motion over time. It's used for fall detection in healthcare, sports analysis, and security. The footgun is confusing it with single-frame object detection.
Attention in Vision: Teaching Models Where to Look
Attention teaches a model where to look in an image by dynamically weighting important pixels or features. It's used in object detection to focus on relevant regions. The footgun is assuming it's free; attention adds computational cost and complexity.
Generative Adversarial Networks (GANs): A Forger and a Detective
A GAN pits two neural networks against each other: a Generator that creates fakes and a Discriminator that spots them. This adversarial game forces the Generator to produce highly realistic outputs, like photorealistic faces. The main footgun is mode collapse.
Patch Embedding: Turning Images into Words for Transformers
Patch embedding chops an image into a grid of squares, turning each into a vector. This lets sequence-based models like Transformers "read" images. It's the core of Vision Transformers (ViTs), but it discards the fine-grained detail inside each patch.
Variational Autoencoders: Learning to Generate Data
A VAE learns to create new data by compressing examples into a "latent space" of core features and then decoding from it. It's used for generative art and data augmentation, but its outputs can be blurrier than those from other models like GANs.
Latent Space: A Map Where Distance is Similarity
A latent space is a map of concepts where distance equals similarity. Similar items are clustered together, which powers image generation and recommendation engines. The footgun is that the map's dimensions are abstract, not human-interpretable features.
Text-to-Image Generation: From Words to Pixels
Text-to-image models act like a digital artist, translating language into visuals. They're used to create art, marketing materials, and prototype designs. The main footgun is prompt ambiguity, which can lead to bizarre or nonsensical images.
Image Captioning: Teaching Machines to Describe What They See
Image captioning teaches a computer to generate a human-readable sentence describing an image, translating pixels into words. This powers accessibility features and better image search.
Visual Place Recognition: Finding Your Location from a Picture
Visual Place Recognition (VPR) answers "Where am I?" by matching a live camera image to a database of pre-recorded pictures. It's a visual GPS for robots and self-driving cars to find their position when GPS is unreliable, like in cities or indoors.
Pretext Tasks: Making Data Teach Itself
A pretext task is a fake problem you invent for a model so it learns from unlabeled data. For example, asking it to predict a missing image patch forces it to learn about objects. This is the core of self-supervised learning.
Semi-Supervised Learning: More From Less Data
Semi-supervised learning uses a small set of labeled data and a large set of unlabeled data to train a model. It's ideal for tasks like image classification where labeling is costly. The footgun: if your unlabeled data is noisy, it can degrade performance.
N-way-K-shot: Classifying with Few Examples
N-way-K-shot is a framework for testing a model's ability to learn from scarce data. It asks: 'Can you classify between N categories after seeing only K examples of each?'
High Dynamic Range (HDR): Seeing More Light
HDR captures a wider range of light and dark than standard images, preventing blown-out highlights and crushed shadows. It's used to show scenes as the human eye sees them. The footgun is thinking HDR is just 'brighter'—it's about more detail in the extremes.
Image Stitching: Creating Panoramas from Overlapping Photos
Image stitching digitally 'tapes' together overlapping photos to create a single, wider panorama or a super-high-resolution image. It's used in phone panorama modes and for creating gigapixel photos. The main footgun is insufficient overlap between shots.
Focus Stacking: Combining Focal Planes for Ultimate Sharpness
Focus stacking creates an image with impossible depth of field by combining the sharpest parts of multiple photos. It's essential for macro, landscape, and microscopy where one shot can't keep everything sharp.
Image Sensors: Converting Light to Data
An image sensor is the digital equivalent of film, turning light into electrical signals. It's the core component in everything from your phone's camera to medical imaging.
ImageNet: The Dataset That Launched the Deep Learning Boom
ImageNet is a massive, human-labeled image library that became the standard benchmark for teaching computers to "see". It's the dataset behind the deep learning revolution, used to pre-train models for photo search and more.
Data Labeling: Teaching Computers How to See
Data labeling is like creating flashcards for an AI. You show it an image and explicitly tell it what's important, like 'this is a cat.' It's essential for training models for self-driving cars or medical imaging.
We are hiring for this. Every open role lists the topics its interview covers, so you can prepare for the real thing rather than guessing.
See open roles