# Localize Screws with Blue Locate

Screws or any other cylindrical object need to be rotated during inspection. Looking not only at one specific line along the rotation axis, but at the full object over several images, brings the advantage that you can see the surface and defects at different angles to the camera and the illumination. For instance, some defects will show best when they are on the center line, others will show better when they are slightly off to the sides.

In this particular set of images, however, the screws are moving across the entire image such that it is advisable to first use a Blue Locate Tool to localize and crop the screw image before feeding it to the Red Analyze tool for detecting any defect.

The objectives of this tutorial are:

- Use the Blue Locate tool to localize and track fuzzy features.
- Generate a geometric model to find the screw's pose.

Note: For more information on the specific steps of setting up the tools, see the .

1. Add the images for the Screw tutorial.
   1. While in training mode, after a Workspace has been added or opened, images can be added through either the Database menu (select Add Images), by pressing Add Images in the display space of the GUI, or dragging and dropping images from a Windows Explorer directory into the View Browser.
2. Add a Blue Locate tool.
3. Adjust the ROI to segment an image, and then press the Scissors icon to process the images based on the new ROI.
4. Set the Feature Size parameter to 80.
5. Define at least two features (for example, the end and the tip of the screw) on at least three images.
6. Press the Brain icon to train the system. Then review the results and manually label the images where the features were not found correctly.
7. If you had to manually label new images, retrain the system and review the results.
8. Right click on an image which has the two features and create a model named "screw".
9. Reprocess the image and make sure the model is correctly found.