Can not install Image acquisition package in Octave - image

Question

According to the relevant wiki page (http://wiki.octave.org/Image_acquisition_package) to install the image acquisition package you enter:
pkg install -forge image-acquisition
I did that in the Octave console and I got an error message:
pkg install -forge image-acquisition
error: get_forge_pkg: could not read URL, please verify internet
connection
error: called from
get_forge_pkg at line 77 column 7
get_forge_download at line 26 column 12
pkg at line 393 column 29
Could you help me install the package? Thank you.

Answer 1

I got the same error on Ubuntu 19.04 after installing Octave from a snap package. The problem was that Apparmor was blocking requests to network resources. The problem was corrected by editing the Octave Apparmor profile file. The following steps fixed the problem:
Add following rules to the file: /var/lib/snapd/apparmor/profiles/snap.octave.octave. The rules should be added to the bottom of the file, just before the closing parenthesis
Add following rules:
owner #{HOME}/.bash_logout r,
owner #{HOME}/.xinputrc r,
owner #{HOME}/.pam_environment r,
owner #{HOME}/.bashrc r,
owner #{HOME}/.bash_history r,
owner #{HOME}/.profile r,
owner #{HOME}/.cache/mesa_shader_cache/index rw,
owner #{HOME}/.sudo_as_admin_successful r,
/usr/share/ca-certificates/mozilla/* r,
/etc/ssl/certs/ r,
/run/systemd/resolve/stub-resolv.conf r,
/etc/hosts r,
/etc/host.conf r,
/etc/ssl/certs/ca-certificates.crt r,
network inet stream,
network inet6 dgram,
network inet dgram,
Reload the Octave Apparmor profile using the command: sudo apparmor_parser -r /var/lib/snapd/apparmor/profiles/snap.octave.octave
Restart Octave
Run the command pkg list -forge

Answer 2

I obtained this error in a network with blocked ports (only 80 and 443 allowed). After connecting to another network the error disappeared.

Answer 3

I'm guessing that you are using Windows. it appears that the Windows versions of Octave currently have an issue making https connections. Bug report #49869 has been created addressing this issue. It appears that the Windows version has not been compiled with proper configuration for ssl downloads, hence Octave cannot read the URL. I expect that pkg update will not work for you either.
Until that gets patched, you should be able to manually install the image acquisition package. Download the package file using the download link at the Octave Forge image-acquisition package page
Then, in Octave, navigate to the location where you saved the package file and type pkg install image-acquisition-0.2.2.tar.gz (or whatever the name is of the version you download).
Finally, since it seems you are using Windows, it is worth mentioning that the image-acquisition toolbox currently has limited (if any) functionality for non-Linux systems. According to the wiki you first linked, there are Linux library build dependencies for that package that are likely unavailable on your Windows system.There has been some recent discussion about this on the Octave help list here and here, but it is still a work in progress.