> For the complete documentation index, see [llms.txt](https://docs.theiamarkerless.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.theiamarkerless.com/axiom-v2025/troubleshooting/error-messages/calibration-errors/field-of-view-coverage-insufficient-less-than-60.md).
# Field of view coverage insufficient (<60%)
### **Explanation**
This error message arises when processing a lens calibration trial, and the detected chessboard patterns fail to coverage a sufficient proportion of the camera view. Theia requires the chessboard pattern detections cover at least 60% of the camera view in order to produce lens calibration parameters for that view. Review the [Lens Calibration Metrics](/axiom-v2025/theia3d-documentation/theia3d-dropdown-menus/calibration-menu/lens-calibration.md#lens-calibration-metrics) section for more detail.
{% hint style="info" %}
While the minimum coverage required is 60%, we recommend aiming for as high coverage values as possible, with >90% coverage being our recommended minimum.
{% endhint %}
### **Possible Solutions**
Check that the correct lens calibration trial videos were loaded. If an [extrinsic chessboard calibration](/axiom-v2025/theia3d-documentation/data-collection/recording-extrinsic-chessboard-calibrations.md) trial is loaded and processed using the Lens Calibration tool, this error can occur.
Check that the chessboard pattern is sufficiently visible throughout the recording. If the videos are too dark or too bright, try using the [Enhance Videos](/axiom-v2025/theia3d-documentation/theia3d-dropdown-menus/tools-menu/enhance-videos.md) to improve the visibility of the chessboard pattern. If the chessboard is too close to the camera during the trial such that pattern is too large and is never fully visible, a new lens calibration trial will need to be recorded.
---
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