Since everyone may have a different idea of what counts as “similar”, and you may want to know: How does Cisdem Duplicate Finder detect similar images? What algorithms does it use? How accurate is the detection? In this guide, you will find the answers.
Cisdem mainly uses three algorithms to compare similar images, Histogram, pHash and Feature points. Understanding these 3 algorithms provides insight into how Cisdem Duplicate Finder detects similar images.
Histogram Comparison
A histogram looks at the overall color distribution in an image: how much red, green, blue, light, and dark it contains.
If two photos share a very similar mix of colors, Cisdem considers them similar.
pHash Comparison
pHash creates a kind of visual fingerprint for an image based on how it looks to the human eye. Even if the picture is resized, saved in another format, or slightly edited, its fingerprint usually remains close to the original.
It’s like recognizing a song. Whether it’s played on piano or guitar, the melody is the same, and you can still tell it’s the same tune.
Feature Points Comparison
Feature points are the distinct details in an image, like corners, edges or unique shapes. This method is very good at spotting similarities even if one image is rotated ,cropped or partly changes.
If you take two photos of the Eiffel Tower, once Cisdem detects the Eiffel Tower from the photos, they will be recognized as similar images regardless of shooting corner, scaling, resolution or other differences.
After understanding the above 3 algorthms, you will be able to choose a proper similarity comparison algorighm through the Similar images setting of Cisdem Duplicate Finder.
Smart Selection: This is the default option. Cisdem will automatically choose the most suitable algorithms based on your computer’s performance and the images being scanned.
Quality First: It uses Histogram and Feature points comparison, if you want to scan out images that are more alike, choose this option.
Speed First: It uses pHash and Feature points comparison, if you need to scan a large number of images or want to scan faster, choose this option.
Conclusion
Cisdem Duplicate Finder employs three algorithms—Perceptual Hash (pHash), Histogram, and Feature Points—to detect similar images. Each algorithm has their own focus, and together，they ensure precise, reliable and comprehensive detection of similar images.
Traci Gordon has worked as a tester in a software company for 8 years, she believes that the best software should be a tool that can help users accomplish what they need with the simplest steps.
