File this one away under dubious uses for a 3D printer.Continue reading Floppy Green Onions
✔ ~/bin $ git clone https://github.com/exiftool/exiftool Cloning into 'exiftool'… remote: Enumerating objects: 727, done. remote: Counting objects: 100% (727/727), done. remote: Compressing objects: 100% (551/551), done. remote: Total 12272 (delta 443), reused 301 (delta 170), pack-reused 11545 Receiving objects: 100% (12272/12272), 15.40 MiB | 12.58 MiB/s, done. Resolving deltas: 100% (10445/10445), done.
For instance, when checking some images I can see that there’s a ton of EXIF information in there, including the precise location where the image was taken:
✔ ~/blog $ exiftool ./2019/11/IMG_20191111_2029432-825x510.jpg ExifTool Version Number : 11.76 [...] GPS Version ID : 188.8.131.52 GPS Latitude Ref : North GPS Longitude Ref : East GPS Altitude Ref : Above Sea Level GPS Time Stamp : 19:29:43 GPS Dilution Of Precision : 16.132 GPS Img Direction Ref : Magnetic North GPS Img Direction : 178 GPS Processing Method : fused GPS Date Stamp : 2019:11:11 [...] GPS Altitude : AA.A m Above Sea Level GPS Date/Time : 2019:11:11 19:29:43Z GPS Latitude : DD deg MM' SS.SS" N GPS Longitude : DD deg MM' SS.SS" E
✔ ~/blog exiftool -gps:all= -r -overwrite_original -P -ext jpg .
This will remove the GPS data for all JPEG files in a folder and all subfolders.
I recently tested two portable disk drives to use for data backups but was appalled by how badly they performed. The drives would alternate between writing quickly (50 – 100MB/s) and stuttering to a halt (250 – 500KB/s), and I could not understand why.
Here’s what that looked like:Continue reading Why Are My Backups So Slow?
MSBuildSDKsPath=/path/to/dotnet/sdk to your user environment, like this GitHub issue says.
A bit obnoxious when things don’t work right out of the box, but after adding this, the steps in https://code.visualstudio.com/docs/languages/dotnet work again.
For some reason, when I was googling the Field of View (FOV) value for the Pixel 2 camera recently, I couldn’t find the answer.
So I thought back to high school trigonometry and measured it myself.
It’s not perfect, but it works:
I took a 30cm ruler and taped it up, then measured how far away the camera needed to be from the ruler to fit the whole thing just inside its Field of View.
d_h = the distance away from the ruler in landscape mode
d_v = the distance away from the ruler in portrait mode
This is what it looks like:
The trigonometry for a right angle triangle means that:
α_h = arctan(15 / d_h) = arctan(15 / 24.5)
α_v = arctan(15 / d_v) = arctan(15 / 32)
and obviously the full FOV_h and FOV_v are double that.
This works with any camera, so if you don’t have the sensor size and don’t want to run through the lens equation, try this method out instead.
Finally, a practical use for all that trigonometry I memorized in high school. (Ok, that’s not true, we used a ton of it in electrical engineering, too.)
In other words, all that the Field of View triangle is saying (and indeed what the tangent ratio is saying) is that:
If we’re holding the camera in landscape mode, then stepping forwards or backwards by 24.5cm will remove or add 30cm of the scene in front of us to the picture.
If we’re holding the camera in portrait mode, then stepping forwards or backwards by 32cm will remove or add 30cm of the scene in front of us to the picture.