What is the difference between image classification and image annotation?

Both are used to organize the images but their process and applications are different. Image classification is a task of extracting information classes from a multiband raster image. While on the other hand Image annotation is marking of images buy humans readable for machines.

Image classification can be used to create thematic maps depending on the interaction between the analyst and the computer during classification and there are two types of classification called supervised and unsupervised. Image annotation is an automatic image tagging used for computer vision to automatically assign metadata in the form of captioning or keywords to a digital image. The method used for annotation is multi-class and image classification.  

The biggest difference between in these two is image classification is usually an automatic task performed by the computers, while image annotation is manually done by the humans to label and annotate the images with recognizable tags.

For an example if Image classification is done by a computer for furniture in a room it will automatically create a bounding box and a confidence interval for its classification. While, on the other hand, image annotation creates a bounding box over the chair and add as a label that, the bounding box surrounds a chair in it.

Unsupervised classification of images is a method which examines a large number of unknown pixels and divides into a number of classed based on natural groupings present in the image values. Unlike supervised classification, unsupervised classification does not require analyst-specified training data. 

Image annotation with automation is a multi-label classification problem that aims at associating a set of textual with an image that describe its semantics. It has potential applications in image retrieval, image description, etc. Thus, Image annotation is usually used on a first stage to create a dataset for training the machines, while image classification is then performed to test if the machine is classifying correctly compared to ground truth. 

Image annotation is more critical task and it is done manually by humans, so seekers need to hire the professionals having significant knowledge and experience in annotating the images in precise manner. Cogito Tech is offering Image annotation services to mark the pictures and images using the right tools and techniques to give the best or accurate results. Cogito is also providing medical image annotation for healthcare industry with quality results.