The task of assigning a label or category to an input image based on its content.Image classification is the task of assigning a predefined label or category to an input image based on its visual content. It is a core problem in computer vision, where algorithms learn to recognize patterns such as objects, scenes, or even galaxy morphologies. In the context of the provided titles, image classification is used to analyze galaxy shapes, identify cardiac conditions from ECG data, and recognize human movements from pose, showing its versatility across scientific domains.
The field gained momentum in 2012 when AlexNet won the ImageNet competition, but earlier work by Yann LeCun on CNNs for handwritten digit recognition in the 1990s laid the groundwork.
Modern image classification relies on convolutional neural networks (CNNs) that automatically learn hierarchical features: edges, textures, and object parts, culminating in a final classification layer. The network is trained on large labeled datasets, adjusting its weights via backpropagation to minimize classification error. For specialized tasks, like galaxy morphology, the same architecture is adapted with domain-specific data and sometimes custom loss functions.
Image classification powers medical diagnostics (e.g., detecting tumors in X-rays), autonomous driving (identifying pedestrians and traffic signs), and astronomical surveys (classifying galaxies into spiral, elliptical, or irregular).
Some image classifiers can be fooled by tiny, imperceptible perturbations to an image, causing them to misclassify a panda as a gibbon with high confidence.



















