The Computer Vision Metrics Handbook
Every score in computer vision, from the ground up. One confusion matrix grows into precision and recall; those scale to many classes, stretch over boxes and masks, follow identities through time, and finally measure images with no ground truth at all. Six chapters — the equations, the intuition, and runnable code.
- 01Classification
Classification Metrics, From the Ground Up: Precision, Recall, F1, ROC and AUC
The confusion matrix and everything that falls out of it — precision, recall, F1, specificity, the precision/recall trade-off, PR and ROC curves, and AUC — built on one running toy example (a backyard cat-cam), with the equations, the intuition, and scikit-learn.
Confusion matrixPrecisionRecallF1SpecificityPR & ROC curvesAUC - 02Multiclass & multilabel
Multiclass and Multilabel Metrics: Micro, Macro, Weighted, and the Difference That Matters
How precision/recall/F1 scale past two classes — one-vs-rest, and the micro/macro/weighted averaging that decides whether rare classes count. Plus multilabel-specific metrics: subset accuracy, Hamming loss, and top-k — all on one running shelter-camera example, with scikit-learn.
One-vs-restMicroMacroWeightedSubset accuracyHamming lossTop-k - 03Object detection
Object Detection Metrics: IoU, AP, and the mAP Everyone Quotes
How detection is scored — IoU to decide a hit, greedy matching into TP/FP/FN, per-class Average Precision as the area under the precision–recall curve, and the COCO mAP@[.5:.95] you see in every paper — all on one running parking-lot example, with torchmetrics.
IoUAPPR curvemAP - 04Segmentation
Segmentation Metrics: IoU, Dice, mIoU, and Panoptic Quality
Scoring masks instead of boxes — pixel IoU/Jaccard and the Dice coefficient (and why they're related), mIoU for semantic segmentation, mask-AP for instance segmentation, and Panoptic Quality for the unified task — on one running cat-mask example, with the equations and code.
IoU / JaccardDicemIoUMask APPanoptic Quality - 05Object tracking
Object Tracking Metrics: MOTA, MOTP, IDF1, and HOTA
Tracking adds identity over time, so its metrics score two things at once — detecting objects and keeping their IDs consistent. MOTA, MOTP, ID switches, IDF1, and the modern HOTA that balances detection against association — on one running door-cam example, with the equations and motmetrics.
MOTAMOTPID switchesIDF1HOTA - 06Image generation
Image Generation Metrics: FID, IS, KID, LPIPS, and CLIPScore
How do you score images with no ground truth? You compare distributions and use learned perceptual models — Inception Score, Fréchet Inception Distance, KID, LPIPS, and CLIPScore for prompt fidelity — on one running cat-generator example, with the equations, the catches, and torchmetrics.
Inception ScoreFIDKIDLPIPSCLIPScore
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