Selecting an ROI Tool for OCR

NI OCR Training Interface

Selecting an ROI Tool for OCR

In OCR applications, you want to focus on specific areas of the image. You can define these specific areas with region of interest (ROI) tools. The following tools are available depending on the orientation of the text in the image:

Rotated Rectangle ROI tool—Use this tool to draw a rotatable rectangle in the image. Click and drag to select a rectangular region. Press the <Shift> key while you click and drag to contain the region to a square, and then click the lines inside the rectangle and drag to adjust the rotation angle.
Annulus ROI tool—Use this tool to draw an annulus in the image. Click the center position and drag to the size you want. Adjust the inner and outer radii, and adjust the start and end angles.

The Annulus Orientation control becomes available when you select the Annulus ROI tool. Choose one of the following options.

  • Baseline Inside—Select this option when the imaginary line on which the bottoms of the letters align is closer to the center of the annulus.
  • Baseline Outside—Select this option when the imaginary line on which the bottoms of the letters align is closer to the outside of the annulus.