Debian-facile

  # sane-find-scanner will now attempt to detect your scanner. If the
  # result is different from what you expected, first make sure your
  # scanner is powered up and properly connected to your computer.

  # No SCSI scanners found. If you expected something different, make sure that
  # you have loaded a kernel SCSI driver for your SCSI adapter.

could not open USB device 0x1d6b/0x0003 at 002:001: Access denied (insufficient permissions)
found USB scanner (vendor=0x04f9 [Brother], product=0x0448 [DCP-L3550CDW series]) at libusb:001:005
could not open USB device 0x046d/0xc05a at 001:003: Access denied (insufficient permissions)
could not open USB device 0x046d/0xc31c at 001:002: Access denied (insufficient permissions)
could not open USB device 0x1d6b/0x0002 at 001:001: Access denied (insufficient permissions)
  # Your USB scanner was (probably) detected. It may or may not be supported by
  # SANE. Try scanimage -L and read the backend's manpage.

  # Not checking for parallel port scanners.

  # Most Scanners connected to the parallel port or other proprietary ports
  # can't be detected by this program.

  # You may want to run this program as root to find all devices. Once you
  # found the scanner devices, be sure to adjust access permissions as
  # necessary.