Detecting Highly-Degraded Occurrences of a Reference Model in Multiple Files

Pattern Finding and Retrieving Results

Objective

Following this tutorial, you will learn how to use EasyFind to detect in multiple images highly-degraded occurrences of a reference model. The degradation can be due to noise, blur, occlusion, missing parts or unstable illumination conditions.

You'll need first to load a reference image, define an ROI where EasyFind will learn the reference model, and set rotation and scaling tolerances for the expected occurrences to search for (steps 1-4). Then you're ready to open multiple files, and perform automatic detection of occurrences (even highly-degraded) of the reference model (steps 5-6).

Reference model

Occurrences of the reference model are found, even if highly-degraded

Step 1: Load the reference image

1. From the main menu, click EasyFind, then New EasyFind Tool.
2. Keep the default variable name for the new PatternFinder object, and click OK. The PatternFinder management dialog box is opened.
3. In the Model tab, click the Open icon, and load the image file EasyFind\Fiducial 1.tif.
4. Keep the default variable name for the new image object, and click OK.

Step 2: Create an ROI to define the reference model on the reference image

1. In the image, right-click and select New ROI... item from the menu.
2. Keep the default variable name for the new ROI object, and click OK. A default ROI is placed over the image (blue rectangle with handles). The ROI management dialog box is opened.
3. Drag the ROI over the reference model and resize it using its handles. Alternatively, enter the following coordinates in the ROI dialog box: 500, 365, 170, 170 for OrgX, OrgY, Width, and Height respectively, and click Close.

Step 3: Learn the reference model

1. In the PatternFinder Model tab, select the ROI object from the source image drop-down list, and click Learn. The reference model is perfectly detected (green edges).
2. In the PatternFinder Search Field tab, select the Image object from the source image drop-down list. Tick the Draw Features check-box.

The model location and feature points are highlighted in the source image.

Step 4: Set rotation and scaling tolerances

● In the PatternFinder Allowances tab, set both angle tolerance and scale tolerance to 25.0.

Step 5: Select multiple images

1. In the PatternFinder Search Field tab, click the Open icon. Select the images files EasyFind\Fiducial 2.tif to Fiducial 8.tif (use the shift key to select multiple files), and click Open.
2. Keep the default variable name for the new Image object, and click OK. The last image appears. The reference model is found, even if highly-degraded.
3. Detection of the reference model is automatically performed. It is not necessary to click Find once a new image appears, as inspection is automatically performed. However, clicking Find will insert the corresponding code into the script windows.
4. Click Results to find more information about the found instance.

Step 6: Browse multiple images

● In the PatternFinder Search Field tab, click the Load Next or Load Previous icons.

The image files appear, and the reference model is automatically detected.