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Really? Do you care to explain? What is the dividend and what is the divisor? Why can dividing a image by its low pass filtered version (or vice versa) be used
by donquichotte 9y ago
Really? Do you care to explain? What is the dividend and what is the divisor? Why can dividing a image by its low pass filtered version (or vice versa) be used to "clean up" the image, i.e. subtract the background, find main colors and cluster similar colors with k-means? What if the divisor has pixels near zero?
- deleted 9y ago[deleted]
- keenerd 9y agoAreas of low contrast become whiter and areas of high contrast become more saturated. It is also more robust than k-means. The author's algo will only work on scanned images. Photographed pages from a book will often have a slight shadow on half the page from the curvature. Blur-divide will clean this up. K-means will think you've used a lot of gray and not figure out that there are multiple background colors.
- 333c 9y agoI can confirm that the author's approach doesn't work well for photographed pages. I took a photograph[0] of a page of notes, and due to the shadow, the results[1] were very unsatisfactory. [0]: https://i.imgur.com/CLZHshT.jpg https://i.imgur.com/CLZHshT.jpg [1]: https://i.imgur.com/rrwca0m.jpg https://i.imgur.com/rrwca0m.jpg