Image segmentation is a simple computer vision and a technique for image processing. Depending on the pixel level, it does the grouping and labeling of cognate regions and segments in a particular image with the help of machine learning and AI.
Every image has mainly two components. That is:
Things: the countable objects such as people, birds, animals, etc in an image are called things.
Stuff: the shapeless and structureless regions in an image are called stuff. They are roads, trees, sky, etc.
The difference between semantic, instance, and panoptic segmentation lies based on how they treat 'things' and 'stuff'.
The difference
Semantic segmentation focuses on the uncountable stuff in a particular image. It analyzes each stuff in the image and assigns a class label based on the pixel representation of the image. For instance, if there are two cars and two people then in semantic segmentation the cars will be identified in one class label and the two people will be put in another class label. Thus, semantic segmentation assigns a unique class label to each of these categories.
Instance segmentation deals with the countable things in a particular image. It can identify every object and instance in an image and assigns a class to it with a distinct identifier. For instance, if there are two cars in instant segmentation then it will identify the two cars separately as car A and car B and will not put both the cars in the same class label.
Panoptic segmentation is the most recent and best version of the image segmentation technique. In this technique, every pixel of an image is assigned a unique semantic label and also a distinctive identifier. Panoptic segmentation prioritizes identifying each thing rather than each stuff. When the problem of overlapping pixels appears, it favors each object instance. Thus, it combines both semantic and instance segmentation.
Evaluation Metrics
As things and stuff are processed distinctively, different evaluation metrics are applied to assess the different identifiers in a segment.
The intersection over union (IOU) metric is mostly used in semantic segmentation. It analyses the similarities between the objects and places them in the same or different class labels.
The average precision (AP) metric is used in instance segmentation. It is a standard evaluation technique that analyses each object on a pixel-to-pixel basis.
The panoptic quantity (PQ) metric is used in Panoptic segmentation. It analyzes unique identifiers for both things and stuff. It is calculated by multiplying segment quantity and the terms of recognition quantity.
Here And Now Applications
These are the various image segmentation techniques and you may also gain insights into the image processing methods if you want to better the real-world applications of these techniques. Some real-world applications of these image segmentation techniques are stated as follows:
- Semantic segmentation helps to identify the objects on the street better when driving an autonomous car.
- Instance segmentation analyzes the object instance and calculates speed and distance with greater depth.
- These techniques have improved the quality of X-ray, MRI, and CT scans and helped in medical advancement.
- The space and satellite images are also improved with the help of these image segmentation techniques.
- The geographical images of rivers, plateaus, agricultural fields, etc are also better visible and captured with these segmentation techniques.
Final Thoughts
The major distinctions between semantic, instance and panoptic segmentation have been discussed here. It provides an overview of these particular image segmentation techniques and how they are applied and used in the real world. Image processing with machine learning has made the understanding and categorization of things and stuff easier and that has been made possible by these image segmentation techniques.