Object detection vs. image classification

Object detection and image classification are two fundamental problems in computer vision that are essential to allowing machines to perceive and comprehend visual data. Even though they both entail image analysis, their goals and methods differ.

Image classification

Image classification is a computer vision task that assigns a label or category to an entire image. The objective is to train a machine learning model to identify and classify images into predetermined categories. The model gains the ability to recognize the key features and patterns within an image that correspond to a certain category.

Workflow

  • Data collection and labeling: A dataset of images is gathered, and each image is labeled with the appropriate class.

  • Model training: A machine learning model, typically a convolutional neural network (CNN), is trained using the labeled dataset to enable it to recognize features and patterns in the images.

  • Inference: The trained model then classifies new, unseen images into predefined categories.

Image classification
Image classification

Applications

  • Image recognition: Image classification models are frequently used for scene identification, object recognition, and facial recognition.

  • Medical imaging: Image classification models are used in diagnosing illnesses or anomalies in medical images.

  • Content filtering: Image classification models help separate images into categories for social media content control.

Challenges

  • Limited information: A single label is assigned to a whole image, omitting information about the background or other objects in the image if any.

  • Inability to localize objects: Image classification does not disclose the position of an object within an image.

Object detection

Object detection is a more difficult problem involving localizing the locations of the objects in an image in addition to categorizing them. The objective is to recognize distinct objects in an image, define their borders, and give each identified object a name.

Workflow

  • Data collection and labeling: In object detection, an image dataset is gathered, similar to image classification, except each image is labeled with the position (a bounding box) and class of each object.

  • Model training: The annotated dataset is used to train object detection models, which are frequently based on architectures such as YOLO (you only look once) or Faster R-CNN (Region-based Convolutional Neural Network).

  • Inference: Using the trained model, objects in new images are located and classified.

Object detection
Object detection

Applications

  • Autonomous vehicles: Object detection models are used by autonomous vehicles for navigation. It helps identify different objects on the way such as obstacles, other vehicles on the road, and pedestrians.

  • Security and surveillance: Object detection models monitor and identify objects, such as people and their activities using camera footage.

  • Retail analytics: In retail analytics, object detection models help track and count the objects on the shelves for inventory management.

Challenges

  • Computationally intensive: Due to the additional task of localization, object detection demands more processing resources than image classification.

  • Fine-grained localization: Determining exact object borders may be difficult, particularly in complicated or congested settings.

Image Classification vs. Object Detection


Image Classification

Object Detection

Scope

Assigns a single label to an entire image

Identifies and localizes multiple objects within an image, assigning labels to each

Output

One label per image

Multiple labels with corresponding bounding boxes for each object in the image

Complexity

Generally less complex

More complex, involving both classification and localization


Use cases

Suitable for tasks where the presence of an object in the image is sufficient

Essential for applications requiring precise localization and identification of multiple objects within the image

Conclusion

Image classification and object detection are essential computer vision tasks with different purposes. Image classification assigns a single label to an entire image, making it suitable for recognizing the presence of an object in the image. Object detection, however, identifies and localizes multiple objects within an image, providing information about their positions and the class to which each object belongs.

Copyright ©2024 Educative, Inc. All rights reserved