Image

Download

Version 2.4: SD-card image | GPG-signature

• Updated openMHA to version 4.15.0
• Updated Raspian
• Updated Linux kernel to version 5.10
• Removed .git folders of openMHA and hearingaid-prototype to keep image size small
• Changed back image compression format to xz (requested by a user)

Version 2.3: SD-card image | GPG-signature

• Updated openMHA to version 4.10.0
• Update Raspbian (but not Linux-kernel)
• Installed playrec
• Added real-time processing example with playrec and GNU/Octave
• Changed image compression format from xz to zstd

Version 2.2: SD-card image | GPG-signature

• Added more recorded samples (from noisy Lisbon/Portugal)
• Increased threshold noise by 6dB (adjusted thresholds in self-fitting GUI accordingly)
• Updated openMHA to version 4.9.0 (which required also changes to openMHA.cfg)
• Update Raspbian (but not Linux-kernel)

Version 2.0: SD-card image | GPG-signature

• Added a selection of recordings which can be used with the self-fitting GUI
• Small improvements to self-fitting GUI
• Tried to fix data inconsistency when recording
• Updated openMHA to version 4.8.1
• Updated Raspbian

Version 1.2: SD-card image | GPG-signature

• INCREASED OUTPUT REFERENCE LEVEL TO 100.8 dB SPL (by 8 dB)
• Revised input and output compensation filter calculation
• and updated coefficients in openMHA.cfg
• Added self-fitting GUI functionality
• Updated openMHA to version 4.7.0
• Updated Raspbian

Version 1.1: SD-card image | GPG-signature

• Re-upload of corrupted image version 1.0

Version 1.0: SD-card image (corrupted image removed) | GPG-signature

• Reduce gain of compressive default gain table by 10dB
• Added license information to many files (GPL)
• Fixed issues when Bluetooth game pad switched off
• Minor UI fixes when device is individualized

Version 0.9: SD-card image | GPG-signature

• Refactored and extended Bluetooth game pad user interface (cf. Tutorial)
• • Menu for individualization including measurement of hearing thresholds with sweeps
• • Start binaural recordings (of 10s duration)
• • Dynamic gain table generation with three parameters for self fitting
• • Improved (text2speech based) dialogs with confirmations
• Changed openMHA config to reduce temporal aliasing
• Lowered level of threshold simulating noise
• Updated Raspbian

Version 0.8: SD-card image | GPG-signature

• Added four exemplary gaintables generated with the openMHA fitting GUI
• Refactored feedback cancellation initialization (init_feedbackcancellation.sh)
• New default key bindings for Bluetooth remote control with many useful options, including: turn a threshold simulating noise on/off, turn amplification on/of, load pre-configured gain tables, power off the device, and re-estimate feedback path
• Text to speech feedback on remote control input (with flite)
• Reduced level of noise used for feedback estimation by 6 dB
• Remove some unneeded files from the system to reduce the download size

Version 0.7: SD-card image | GPG-signature

• Added proof of concept code for bluetooth remote control (tested with "8bitdo zero")
• Refactored feedback measurement/visualization/cancellation code for better re-use
• Added script to measure remaining feedback after compensation

Version 0.6: SD-card image | GPG-signature

• Improved robustness of feedback path estimation (update_configuration.m)
• Adjusted microphone recording level by 1.5 dB to better match the average sensitivity
• Added tool to perform recordings in intervals (record.sh)
• Updated openMHA to version 4.6.1
• Updated Raspbian

Version 0.5: SD-card image | GPG-signature

• Set calibration values according to Calibration

Version 0.4: SD-card image | GPG-signature

• Updated openMHA to version 4.6.0
• Updated Raspbian

Version 0.3: SD-card image | GPG-signature

• Updated openMHA to version 4.5.8
• Updated Raspbian (should now work with Raspberry Pi 3 Model B+)
• Reduced period/fragment size to 48 samples to reduce latency (now approx 3.7 ms w/o algorithms)
• Added preliminary compensation filters to get closer to a "transparent" perception
• Added a simple static feedback cancellation (WARNING: this will cause the playback of a white noise with high level at boot time to measure the feedback path)
• Removed coherence filters and frequency shifter
• Stripped comments and default values from openMHA.cfg
• Added the possibility to play a continuous threshold simulating noise for demonstration purposes (disabled by default)

Version 0.2: SD-card image | GPG-signature

• Updated openMHA to version 4.5.3
• Updated Raspbian
• Changed default gain table to no amplification. You will probably want to change the gain table in order to hear an effect.
• Added tools to measure feedback and IO-functions

Version 0.1: SD-card image | GPG-signature

• Initial release

Creation

To create the images that are available for download the following steps are performed.:

1. Mount the two partitions of the SD card
2. Add init=/usr/lib/raspi-config/init_resize.sh to the first line of the file 'cmdline.txt' on the boot partition
3. Remove any private or unneeded data from the root partition, e.g. '/home/pi/.bash_history'
4. Unmount the two partitions
5. Run zerofree on the root partition
6. Copy the whole SD card content to an image file with diskdump (dd)
7. Shrink the image to the minimal size, e.g., with the script provided here: https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=58069#p436666
8. compress the image with zstd --long -19

Signing

I (Marc René Schädler) sign the released images with GPG. The signatures can be found in the repository: https://github.com/m-r-s/hearingaid-prototype/tree/master/signatures