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CNNs & Image Recognition

From the convolution to ResNet, efficiency, and detection

01 ·CNNs & Image Recognition·FREE·8 min read Image Classification from Scratch — The Invention of the Convolution Feed a photograph straight into a fully connected layer and you get over a hundred million parameters — and a model for which the same cat, moved a few pixels, is an entirely different input. The convolution solves both with one idea: slide a small window. Kernels, stride, padding and pooling, ending with softmax turning scores into probabilities. 02 ·CNNs & Image Recognition·★ MEMBER·PAPER·9 min read Object Detection from Scratch (from YOLO to DETR) A from-zero guide to object detection: the classic toolkit of two-stage detectors, anchors, and NMS — and how DETR reframed the whole problem to make all of it unnecessary. Primary source: the DETR paper. 03 ·CNNs & Image Recognition·★ MEMBER·PAPER·8 min read The CNN Family Tree — From AlexNet to ResNet and EfficientNet A decade of CNNs told as two campaigns — the race for depth and the race for efficiency. ReLU, residual connections, and compound scaling explained from scratch with metaphors, interactive figures, and code. 04 ·CNNs & Image Recognition·FREE·9 min read The Autonomous Driving Perception Stack from Scratch — What Cameras and LiDAR Each Bring to the Table How a self-driving car figures out what is around it, starting from sensor physics. We cover the complementary strengths of cameras and LiDAR, the bird's-eye-view grid where all sensors meet, occupancy grids grown by Bayesian updates, and the tug-of-war between safety requirements and compute budgets — no prior knowledge assumed. 05 ·CNNs & Image Recognition·★ MEMBER·11 min read Anomaly Detection from Scratch — Learning From Normal Alone Why an AI can learn from good units alone on a factory floor where defect samples barely exist. Two rulers — reconstruction error and density estimation — built up from metaphor to equations, all the way to the part that decides everything in practice: choosing the threshold. 06 ·CNNs & Image Recognition·★ MEMBER·9 min read Medical Imaging AI — Validation Design Comes Before the Accuracy Number An AI that scored beautifully on your own hospital's data turns out to be useless at the hospital next door — a failure that has been reported over and over in medical imaging. Sensitivity and specificity, the way prevalence flips the meaning of a positive result, internal versus external validation, what site-to-site variation actually is, and what regulators are really reviewing: building up, from first principles, the habit of questioning the validation design before the accuracy figure. 07 ·CNNs & Image Recognition·FREE·PAPER·9 min read The ImageNet Moment — The Day Deep Learning Won In 2012 an image-recognition contest saw its error rate fall from around 26% to 15% in a single year. Neural networks had existed for three decades — so why then? This is the story of the moment data, compute, and method finally lined up, told down to the technical details. 08 ·CNNs & Image Recognition·★ MEMBER·PAPER·8 min read Paper Walkthrough: TurboVLA — Kick the LLM Out of the Loop and Run a Robot Policy at 32 Hz on an RTX 4090 with Under 1 GB of VRAM Mainstream VLA models route every control step through a large language model. TurboVLA removes the LLM and fuses vision and instructions with lightweight bidirectional cross-attention instead — hitting 97.7% on LIBERO with 0.2B parameters, 31.2 ms latency, and 0.9 GB of VRAM. A from-scratch walkthrough of the paper. 09 ·CNNs & Image Recognition·★ MEMBER·PAPER·10 min read Paper Walkthrough: PhiZero — A World Model That Reasons in a Language of Physics Before It Renders A close read of PhiZero, which reasons about how the world will change in a discrete 'physical language' learned self-supervised from video, and only then renders the footage — instead of predicting pixels directly. The two-stage tokenizer and reasoner, the top spot on Physics-IQ Verified, zero-shot motion transfer, and the limitations the paper itself admits.