Alignment Block

Use the Alignment Block page to Capture a Template Image as a reference for your inspection program, and use pattern-matching to locate and orient parts for relative inspection.

Capture Template Image - Click this button in the top right corner of the menu to capture (or re-capture) a template image. Capturing a Template Image is a required step for ALL recipes.

Skip Aligner - Enable this toggle to skip the remaining Alignment Block setup and use fixed-position Regions of Interest. This is recommended for applications with parts that are fixtured or presented to the camera very repeatably.

Template Regions - Click + Square or + Circle to add a Template Region of that shape to the Template Image. The OV20i will detect edges inside these Template Regions and try to locate parts by matching similar edge patterns.

Ignore Template Region - Click here to access a brush tool that can be used to erase unwanted edges from any Template Region. This is used to mask out unwanted edge noise and focus the Alignment on clear, repeatable edge patterns.

Rotation Range - Enter an angle of 0-180 degrees to constrain the amount of rotation the Alignment Block will tolerate. Set this to 180 to find parts rotated at any angle. Set this to 0 to find only parts that match the template image angle.

Sensitivity - Adjust the slider to increase/decrease edge-finding sensitivity. Higher sensitivity settings will find more edges, and lower sensitivity settings will find fewer edges.

Mode - Select Fast or Accurate to augment the performance of the Alignment Block. Accurate Mode is recommended for the majority of applications.

Confidence Threshold - Use this slider to set the minimum confidence required for an Alignment to be considered valid (100% indicates an identical match). This threshold should fall between 60-90% for consistent Alignment.

Enable Live Preview Mode - Runs the alignment block in real-time allowing you to test its performance and confidence on different situations and parts.

Alignment Block Best Practices

1. When placing Template Regions, focus on edges that are simple, unique, and consistently visible across all parts. Try to avoid edges that may be obscured by defects, or edge patterns that vary from part to part.

2. Edges found inside a Template Region are highlighted green. Red highlights indicate that there are not enough edges found for valid alignment. You can increase sensitivity or add more Template Regions to increase the edge count (below).

3. Use the Ignore Template Region tool to filter out edge noise from the Alignment. ‘Edge noise’ includes any highlighted edges that do not represent a simple, unique, and consistently visible pattern. For example, a Template Region might inappropriately highlight textured surfaces, reflections, debris, or other features as edges in your Template Image.

Tips

1. If Alignment is inconsistent or fails when testing on different parts, your Template Regions may be set up on a pattern that is not simple enough, or not consistently visible across all parts. Try reducing the amount of edges, or choosing a different pattern to focus on for Alignment.

2. If Alignment has frequent ‘false positives’ where it matches to something other than the part you want to find, you may have chosen a pattern that is not unique enough. Try increasing the Confidence Threshold to screen out the false positives, or add Template Regions and/or Sensitivity to make your Alignment pattern more specific.