What is Image Annotation ?

September 19th, 2020 | by Almir

What is Image Annotation


Years back, human efforts were used to carry out a lot of activities. They were needed in various sectors that use the human working capacity to carry out their businesses. Today, the world is experiencing a widespread technology revolution whereby information technology (IT) is fast dictating the pace and the scheme of events. With the use of computers, brilliant ideas have been transformed into excellent innovations like artificial intelligence and machine learning. These two innovations have made life, and business processes become easier. Machine learning and artificial intelligence rely on the use of a computing algorithm to replicate intelligent human behavior. These behaviours include automatic speech recognition, augmented reality, and neural machine translations. That said, the success of these technological innovations in various sectors led to intensive research on the use of computers to visualize and interpret images. With different software, computer vision makes an effort to activate the machine eyes to see and interpret images.

Technology has proved that computer vision can give the human race and scientists autonomous vehicles, unmanned drones, and facial recognition. However, this extraordinary development can be enjoyed with the introduction of image annotation in the technology world. Image annotation is an important task when it comes to computer vision.   As useful as this technology may be to the human race, there are lots of hidden information that are needed to be unraveled to understand its function fully and uses in the world. Therefore, today, I will be telling you all you need need to know about image annotation.

                         What is Image Annotation ?

Image annotation is an innovative computing technology where a human-powered task is used to manually identify and define regions in an image and also create a text-based description for the areas specified in the image. Image annotation catalyzes the pattern recognition process of the computer vision system when it is presented with a new image or data. The rate at which patterns or labels on images are being recognized differs. Images or data with similar labels are recognized easier and quicker than those with different labels. Image annotation technology is mostly used by artificial intelligence (AI) engineers to give information about an image for developing a computer vision model.


Different Techniques of Image Annotation


  1. 2D Bounding Box

The 2D bounding box technique is one of the significant techniques used in annotating images. In this method, annotators create a box around the object of interest at a particular frame and location. Also, you create place anchor points at the edges of each object. Many a time, the object may look the same. In this instance, you can draw boxes of all the objects in the image. Also, when there are different objects in the location, you must draw boxes around each object. For instance, if you have cars, bicycles, and pedestrians, you should draw boxes around each of them. After drawing the box, the annotator will choose labels that are a perfect fit to object in the box.

  1. 3D Bounding Box

The 3D bounding box, also known as cuboid, is a technique that is similar to the 2D bounding box. In this technique, the annotator creates a box around each image. They also place a point anchor point on the edges of each object. The boxes are created to cover a specific location and frame. However, the difference here is that the boxes can show the depth of the object been annotated.

  1. Polygon Annotation

Polygon annotation is an excellent image annotation technique annotator can use for objects that have irregular shapes and sizes. This method is useful because 2D and 3D bounding boxes can only annotate images with regular shapes. In this technique, polygons are created around the image of interest. This makes it easier to predict accurately the image’s volume and position within the polygonal space.

  1. Polylines

Polyline annotation is a fantastic annotation technique that is mainly used when you desire to make your computer vision system aware if annotating boundaries, splines, and lines. Annotators can also use the polyline technique to plan trajectories in drones. In this technique, straight or curved lines are created on images. Then the annotator would be left the option of annotating sidewalks, lanes, powerlines, and some other boundary indicators.

  1. Keypoint

Keypoint tracking is an image annotation technique that annotators can use to determine the outermost part of an object. They also use it to determine the size and position of essential parts of the object. For instance, if you are annotating a car, it vital parts like side mirrors, headlights, and wheels are determined.

  1. Semantic Segmentation

If you wish to annotate image by dividing it into different segments or regions, you can choose semantic segmentation. For example, you can annotate the image of your car pack. A typical car pack comprises of trees, grasses, and sidewalk. Each of these components is separated into different segments. Then they are annotated separately. While using a semantic segmentation technique to carry out image annotation, you may need to adjust the threshold of the semantic segmentation algorithm. This will help it annotate any kind of image you desire.


Steps in Image Annotation

  1. Analyze Project Limitations

The first step to annotate a given image is to analyze the restriction on the project. Therefore, analyzing the project give annotators an idea about the project and its constraints.

  1. Use Appropriate tools

Many tools have been made available for annotators to use. However, you need to choose the right tool for the kind of image you want to annotate. The analysis you have previously done will assist you in choosing the best tool for a specific image.

  1. Use Appropriate Technique

After you have selected the right tool, you need to employ the correct technique to annotate a particular image. This involves studying the project instruction. Images produced with the proper technique can be used as training data.

Best Company that Provide Image Annotation Service


LabelOps is one of the best companies that provide excellent and fantastic imaging annotating services worldwide. It has the lowest hourly rates and best accurate annotations for the best training dataset. The company has a team of experts and professionals that specializes in machine learning, artificial intelligence, and image annotation. It also has state-of-the-art facilities that are used to carry out annotating services. LabelOps is an image annotating company that is certified and provides fantastic customer support services when you consult them for image annotating services.

The company has a track record of outstanding and excellent services on its previous and ongoing contracts. Their professional services are rendered to IT customers and other stakeholders at affordable prices.


Image annotation is vital to artificial intelligence engineers. Today, I have discussed crucial points you need to know about Image annotation. Please read through it and get informed about the image and text-based description technology.

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