# Feature Extraction Modes

As you configure a Checkerboard Calibration tool you must choose a mode for extracting the features of your calibration plate. The tool supports the following modes for older VisionPro applications that use either a checkerboard or grid-of-dots plate:

- Checkerboard
- DotGrid

Cognex does not recommend using either the Checkerboard or DotGrid modes for new vision applications. Instead VisionPro offers the following exhaustive or efficient feature extraction modes:

- CheckerboardExhaustive for plates with or without the "L" fiducial or CheckerboardExhaustiveMultiRegion for plates with DataMatrix fiducial marks.
- CheckerboardEfficient for plates with or without the "L" fiducial or CheckerboardEfficientMultiRegion for plates with DataMatrix fiducial marks.

In general, the efficient modes will execute faster than the exhaustive modes with the following exceptions and limitations:

- The number of features extracted in the efficient modes might be lower than the number of features extracted in the exhaustive modes.
- The accuracy of the features extracted in the efficient modes might be lower than the accuracy of the features extracted in the exhaustive modes. This is more likely to be true when the quality of the calibration image is poor (e.g. highly distorted, and/or low resolution, and/or poor contrast).
- When lower accuracy features are extracted, the process of computing a nonlinear calibration might take longer. The nonlinear calibration algorithm does more work to produce minimal error results from less accurate features. Because of this, when the calibration image is of poor quality, overall calibration time using efficient feature extraction may actually exceed overall calibration time using exhaustive feature extraction, and the overall quality of the calibration (as indicated by the RMS Error) might be lower.

You might need to experiment with the efficient and exhaustive modes to see which works best with your application.