Digital image processing (DIP) refers to the use of computer algorithms to perform operations on digital images. It involves manipulating and analyzing images to enhance their quality, extract information, or transform them for various applications. Unlike analog image processing, which uses physical objects like lenses and filters, DIP uses numerical representations of images.

Core Concepts: A digital image is represented as a grid of pixels, each with a numerical value representing its intensity or color. DIP algorithms operate on these pixel values.

Key Stages/Techniques:

1. Image Acquisition: Capturing the image using sensors (e.g., cameras, scanners).
2. Image Enhancement: Improving the visual quality of an image for human interpretation or further processing. Techniques include contrast stretching, histogram equalization, noise reduction (e.g., median filtering), and sharpening.
3. Image Restoration: Removing degradation from images due to factors like blur, noise, or atmospheric interference, often using mathematical models of the degradation process.
4. Image Transformation: Changing the image's domain, such as converting it from spatial domain to frequency domain (e.g., using Fourier Transform) for easier analysis or compression.
5. Image Compression: Reducing the amount of data required to represent an image, facilitating storage and transmission (e.g., JPEG, PNG).
6. Image Segmentation: Partitioning an image into multiple segments or objects, often to locate objects and boundaries (e.g., edge detection, region growing).
7. Feature Extraction: Identifying and quantifying specific characteristics or patterns within an image, such as shape, texture, or color.
8. Image Recognition/Classification: Assigning labels to objects or regions in an image based on extracted features, often using machine learning algorithms.

Applications: DIP is widely used in remote sensing (satellite imagery analysis), medical imaging (MRI, X-ray), computer vision, security (facial recognition), industrial inspection, and graphic design. It is a fundamental technology enabling machines to 'see' and interpret visual information.