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Comment by reaganing | Hacker News Reader

Not really a fan of Moleskine's notebooks, but this is interesting.

But, Evernote's Page Camera feature that was added to the iOS app does seem to work just fine with other paper (I tested Field Notes w/ graph paper). It's just 'optimized' for the paper in these notebooks, whatever that means.

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I love Moleskine, but that just made me all the more sceptical about the "optimized" dotted paper pattern. That just screams gimmick to me, especially looking at the picture provided.

If it does make a significant usability difference, that would be pretty cool and I'd love to get some insight into why dotted lines would be simpler for image processing software to work with than straight lines, but... For now, I'm gonna keep on trying to bury myself with post-it notes...

The grids or lines on the notebook are dotted. Their algorithm knows the geometry of those dots ahead of time, so it can exploit that fact to figure what the orientation is suppose to be.

But the geometry of all lined notebooks is effectively the same: horizontal parallel lines inside a rectangular shape. For this type of application I don't think any more geometry is needed.

Unless scale is important but I can't see how that could be.

If I had to guess, I'd say the extra geometry is useful because, 1: the dotted pattern is less likely to be confused with user writing/drawing, and 2: they have one specific notebook that they know works seamlessly with their current algorithms without a lot of extra field testing against different notebooks.

It most likely helped a good amount in bringing this feature to market as quickly as possible, and it'll be interesting what they do with the dotted pattern concept in the future (I see it either fading into an edge case of the software that becomes a technical debt for the remainder of its lifetime as the algorithms for handling the base case of any arbitrary notebook paper improve, or evolving into the base of an Evernote certification process for notebooks).

Personally, for me this feature is the tipping point between "yeah, Evernote seems kinda cool" and "I'm actually considering using Evernote (assuming the feature finds its way to Android)". The only improvement I would make that would really seal the deal would be the ability to fax all my notes to Evernote instead (seems like much less a pain in the ass for digitising volumes of notes than meticulously photographing each page), though I suppose that as long as they support manual uploading of images through their desktop site this would be fairly trivial to script myself.

The issue is that it would be much harder for an algorithm to figure out whether a line was something you drew or the grid lines of the paper, especially if the orientation is off. If the algorithm only has to look for a dot pattern with a known relative spacing, it makes the problem much easier.

for one, the paper has alignment dots that evernote uses to square the image perfectly even if the camera is held askew.

Can't a generalized line/grid detection algorithm be used to correct the skew from photos of any lined or squared note paper?

$25/notepad is way of the charts for the types of notes and sketches that I actually need a notepad for.

Yep. Edge detection + affine transform. No need for any fancy dots.

Use a Hough transform on the edge detection to get the right lines (you only want the longest, straightest ones). Then apply the affine transform back.

It gets harder if the notebook doesn't lie flat, though.

The limited selection is even worse than the price. I vastly prefer Moleskine's soft cover notebooks, and these are apparently only available in hard cover. Then again, aside from "disaster recovery", the flatbed scanner I already use to scan notebook pages probably works better than the iPad's camera even with special deskew logic anyway.

Have you used the 5 x 8.25 size with grid lines? I was a skeptic until then. Now I swear by them.

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