Thursday, December 20, 2012

Vectorizing scans

I am always unhappy about the way my scanned handwritten documents look. Pencil looks especially bad. I have earlier used the fantastic inkscape to trace bitmaps and create vectorized versions of my scans, with success. But the process is somewhat cumbersome, and I tend to forget how to do it between the times I need it.

The result is worth it, though. Black is real black, and since it produces vector graphics the edges are not pixelated, even if you zoom in.

Original scan, grey and pixelated.

After the vectorizing, black and white, and no visible pixelation (you may distinguish pixels here, since I converted the image from pdf to png).

Here comes a way to do it in one command from a terminal.

Wednesday, August 8, 2012

Mounting an exFAT disk in Ubuntu

I recently had trouble mounting an external drive in Ubuntu 11.04.

I take system disc images with dd, from Ubuntu booted with a live CD. One of the steps of the process is to mount the drive where the backup file is to be stored. To do that I need to know the format of the drive.

My problem was that fdisk -l told me that the destination drive was HPFS/NTFS, which was wrong. Connecting the drive to a Windows machine made it clear that it was formatted as exFAT.

Ubuntu does not support the exFAT format in its current distribution (at least not in 11.04), which explains why fdisk gave the wrong information.

If you have trouble connecting an external drive to your Ubuntu install, and fdisk tells you it is NTFS, read on...

Sunday, June 3, 2012

Making system backup smaller

While taking a snapshot of my system disk, I discovered that the image file produced by dd had grown way too large. This post explains what happened and how to solve it.

Sunday, February 19, 2012

Data backup with rsync

After years of backing up personal data on an external disk and keeping the disk in a cupboard, I finally got to implement something a bit more safe.

Off site copy

Having your backup disk at home protects you against data loss in case of disk failure. Should your house burn down, your backup disk would not help much.
If burglars pay you a visit and take your computer, they may just as well take all your electronic equipment as well, including your backup copy.