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Combine pixel-perfect centering measurement with AI analysis of corners, edges, and surface for the most accurate card grade possible.
Take or upload photos of the front and back of your card. Higher resolution gives better edge detection results.
Sobel edge detection auto-detects the card borders. Fine-tune the 8 guide lines to mark the inside and outside edges on all 4 sides.
AI examines corners, edges, and surface condition while using your measured centering as ground truth. You get 4 subgrades and a combined overall grade.
Same AI analysis, same cost — Precision Grade adds measured centering data
| Quick Grade | Precision Grade | |
|---|---|---|
| Centering | AI visual estimate | Pixel-perfect measurement |
| Corners | AI analysis | AI analysis |
| Edges | AI analysis | AI analysis |
| Surface | AI analysis | AI analysis |
| Speed | ~10 seconds | ~40 seconds |
| Cost | 1 credit | 1 credit |
Centering is the one subgrade that is mathematically deterministic. Unlike corners, edges, and surface — which require subjective judgment calls — centering is a ratio. The left border is either 55% of the total horizontal space or it isn't. There's no ambiguity.
That makes centering the one area where measurement can outperform estimation. AI visual centering analysis works well on most cards, but it can misread centering on foil cards, holographic patterns, dark or black borders, and vintage cards with irregular printing.
The difference matters at the margins. A card that's 55/45 centered earns a centering subgrade of 9 or higher at most grading companies. At 60/40, it drops to an 8. That single subgrade shift can move the overall grade from a PSA 10 to a PSA 9 — and the price difference between those two grades can be 2-5x or more.
Computer vision algorithm automatically detects the card's physical borders by finding high-contrast intensity gradients in the image.
Mark the inside and outside edges on all 4 sides. Inside edges define the printed border, outside edges define the physical card edge.
Your guide line positions are converted to exact centering ratios (e.g., 52/48) and injected into the AI prompt as ground truth data.
The centering subgrade is calculated directly from the measurements — it overrides the AI's visual centering estimate for maximum accuracy.
Explore our other free card grading tools