The fundamentals of digital image processing involve a series of steps to manipulate and analyze images using computational algorithms. The key steps involved is as follows:
IMAGE ACQUISITION: The process of capturing images using various sensors such as cameras, scanners, or satellite instruments. Images can be acquired in different modalities including visible light, infrared, radar, or multispectral bands depending on the application.
IMAGE PREPROCESSING:
- IMAGE CALIBRATION: Correcting distortions and artefacts introduced during the image acquisition process, such as sensor noise, lens aberrations, and geometric distortions.
- IMAGE RESIZING AND SCALING: Adjusting the spatial resolution and size of the image as required for further processing.
- COLOR CORRECTION: Ensuring consistency and accuracy in color representation, particularly when images are captured under different lighting conditions or sensors.
- NOISE REDUCTION: Removing unwanted noise from the image using filtering techniques such as median filtering or Gaussian smoothing.
- IMAGE REGISTRATION: Aligning multiple images acquired from different sensors or viewpoints to the same coordinate system for accurate comparison and analysis.
IMAGE ENHANCEMENT:
- CONTRAST ENHANCEMENT: Adjusting the dynamic range of pixel intensities to improve visibility and highlight specific features of interest.
- HISTOGRAM EQUALISATION: Enhancing image contrast by redistributing pixel intensities to achieve a more uniform histogram distribution.
- SHARPENING: Increasing the edge contrast and spatial resolution of the image to enhance fine details and improve visual clarity.
IMAGE RESTORATION:
- DEBLURRING: Removing blur caused by motion or defocus to restore sharpness and clarity in the image.
- DECONVOLUTION: Recovering the original image from its degraded version by modeling and compensating for the blurring process.
IMAGE SEGMENTATION:
- THRESHOLDING: Dividing the image into regions or objects based on pixel intensity thresholds.
- EDGE DETECTION: Identifying boundaries between different regions in the image by detecting abrupt changes in pixel intensity.
- CLUSTERING: Grouping similar pixels or image regions into clusters based on their features such as color, texture, or spatial proximity.
FEATURE EXTRACTION:
- OBJECT DETECTION: Identifying and localising specific objects or patterns within the image, such as faces, vehicles, or buildings.
- TEXTURE ANALYSIS: Quantifying the spatial arrangement and variation of pixel intensities to characterise surface textures in the image.
- SHAPE ANALYSIS: Extracting geometric properties of objects, such as size, orientation, and curvature, for further analysis and classification.
IMAGE ANALYSIS AND INTERPRETATION:
- CLASSIFICATION: Assigning semantic labels or categories to image pixels or regions based on their features and attributes.
- OBJECT RECOGNITION: Identifying and categorising objects within the image based on their visual appearance and context.
- QUANTITATIVE MEASUREMENT: Extracting numerical information and statistics from the image to quantify specific properties or phenomena of interest.
These steps represent a general framework for digital image processing, which can be tailored and customized according to the specific requirements and objectives of each application.