Regardless of the specific tool, the process generally follows these steps: Scalar plot digitizer - File Exchange - MATLAB Central
: For a manual, code-based approach, you can use the built-in ginput function. A common workflow involves loading an image with imread , displaying it with imshow , and then using ginput to capture pixel coordinates and transform them into graph coordinates using a calibration algorithm .
Several powerful MATLAB-based tools and blog resources exist for digitizing (extracting data from) plots in images. The most effective approach typically involves using specialized GUI tools from the MATLAB Central File Exchange . Top MATLAB Plot Digitization Tools plot-digitizer-matlab
: Specifically designed to digitize X-Y scatter plots from pictures. It is frequently updated and used for basic 2D data extraction.
: Detailed walkthroughs for tools like Gravit (or GRABIT) demonstrate how to load images, calibrate linear or log axes, and export data directly to the MATLAB workspace. General Digitization Workflow Regardless of the specific tool, the process generally
: This tool uses an automated algorithm that can trace a graph from an initial point, picking the nearest point to the previously digitized one to speed up the process. Key Tutorials and Blog Resources
: For those looking to automate the process, Steve Eddins’ blog post Automating Data Extraction provides a deep dive into using the Image Processing Toolbox to extract data from line plots. : Detailed walkthroughs for tools like Gravit (or
: A modern app that handles various image formats and supports complex digitizations, including log-scaled, tilted, skewed, or polar plots. It can re-interpolate data to a specified sampling rate, which is useful for further analysis like surface interpolation.