Introduction
Template matching is a fundamental concept in computer vision that allows you to find a smaller image within a larger image. This technique is widely used in various applications, including object recognition, image analysis, and pattern detection. In this article, we will explore the concept of template matching and provide a step-by-step guide on how to apply it using Roboflow Workflows, a web-based computer vision application builder.
What is Template Matching?
Template matching allows you to find a reference image within a larger image. This is useful for object identification, where you know the shape of an object you expect to find within a larger image. Template matching falls within the category of classical computer vision techniques. Modern, deep-learning based approaches are able to more effectively identify objects. To learn more about object detection and deep learning, refer to our "What is Object Detection?" Guide.
Step #1: Create a Workflow
To get started, create a free Roboflow account. Then, navigate to the Roboflow dashboard and click the Workflows tab in the left sidebar. This will take you to the Workflows homepage, from which you can create a Workflow. Click "Create Workflow" to create a new Workflow.
Step #2: Add a Template Matching Block
Click "Add Block" in the top right corner of the Roboflow Workflows builder, then search for "Template Matching". When you add the block, you will be asked to configure two variables: an input image that will be run through the template matching algorithm, and a reference "template" image.
Step #3: Add a Visualizer
By default, Workflows returns a JSON response with the information computed from your Workflow. You can also add visualizer blocks to create visual representations of the results from your Workflow. Let’s add a Bounding Box Visualization so we can see the exact regions where our template matches in an image.
Step #3: Test the Workflow
Your final Workflow should look like this. In this Workflow, we accept a template and an input image, apply template matching to the input image using the template, visualize results from template matching, and return the template matching information in JSON, and a visual response showing the matched templates.
Conclusion
You can use template matching to localize objects in an image. In this guide, we walked through how to apply template matching with Roboflow Workflows, a web-based computer vision application builder. We created a new Workflow, added a template matching block, then tested the Workflow with a reference and input image.
Frequently Asked Questions
Question 1: What is template matching?
Template matching is a computer vision technique that allows you to find a smaller image within a larger image.
Question 2: How do I apply template matching using Roboflow Workflows?
To apply template matching using Roboflow Workflows, you need to create a new Workflow, add a template matching block, configure the input image and reference template image, and add a visualizer block to visualize the results.
Question 3: What is the purpose of the template matching block in Roboflow Workflows?
The template matching block in Roboflow Workflows is used to find a reference image within a larger image.
Question 4: Can I use template matching for object recognition?
Yes, template matching can be used for object recognition, where you know the shape of an object you expect to find within a larger image.
Question 5: Are there any limitations to template matching?
Yes, template matching has limitations, such as the need for a good quality reference image and the potential for false positives or negatives.
