Active acoustic defogging
Camera and sensor lens defogging: instant removal of condensation, mist and water droplets on optical glass and sapphire windows — a low-power alternative to lens heaters, active only when needed.
When transparent optics fog over, vision systems go blind
Temperature swings, humidity, rain and mist leave fog, condensation and droplets on glass and sapphire optical windows — outdoors, inside vehicles and inside the body. Today's workarounds all fall short.
Constant power drain, minutes of lag, heat noise near the sensor, and baked-on residue as water evaporates.
Break, freeze, obstruct the view. Useless against internal fog.
Degrade under UV and abrasion. Cannot remove water already present.
Acoustic lens defogging. Nothing in the optical path.
Sense & excite
Actuators around the rim sense fog on the glass and switch on automatically, outside the field of view.
Wave propagation
Acoustic waves travel across the rigid glass or sapphire window.
Droplet ejection
Fog and droplets are propelled off the window to a gravity drain. 100% aperture clarity, no coating to wear.
It knows when the lens fogs
The same acoustic system senses the state of the glass surface and clears it only when needed. No extra sensors, no always-on power draw.
50% less energy per clear
Our next-generation design targets half the energy of today's Gen 1 results, at the same clearing speed.
18× faster recovery at a fraction of the energy
Measured on a commercial outdoor surveillance camera testbed at 0W (passive control), 1W, 3W and 6W driving power.
Time to 90% clear, relative to passive control
How much faster the optical window reaches 90% clear area compared with no actuation (0W). At 90% the critical aperture is already usable for computer vision and human recognition.
Passive evaporation: several minutes
90% clear 6× faster
90% clear 9× faster
90% clear 18× faster
Cumulative energy over 60 minutes
Fog returns, so the lens must be cleared again and again. A low-power lens heater draws 0.5–1W the whole time. SonoFog senses the surface itself and switches on automatically only when fog re-forms — each step in the line is one clearing event. Shown for heavy re-fogging (every 2 minutes), with the fast 40 J clear and the standard 15 J clear.
- Heater 1W continuous3,600 J
- Heater 0.5W continuous1,800 J
- SonoFog fast · 40 J per clear (6W)1,200 J
- SonoFog standard · 15 J per clear (1W)450 J
less energy than a 0.5–1W heater with standard 15 J clears, even under heavy re-fogging
SonoFog 15 J clearing events for the energy of one hour of heating
~7.5 J per standard clear: 50% lower than Gen 1
What you are looking at
Recordings of the wetted optical cover window on the camera testbed, at different driving powers. Watch the droplets being propelled off the window acoustically while the passive control stays covered.
Better than heating on every axis
Heating is today's default because it is simple. But a heater never removes water, it only waits for it to evaporate, and it pays for that every second it is on.
| Axis | Continuous heating | SonoFog |
|---|---|---|
| Energy | Always on, 0.5–2W around the clock | Runs only when fog is sensed, a few joules per clear |
| Speed | Minutes of thermal lag to warm the glass | Seconds: 100% clear in 8–26 s |
| Residue | Evaporation bakes salt, minerals and chemical films onto the glass | Droplets and contaminants are ejected to a drain, not baked on |
| Off-grid power | Drains batteries in under a day | Months-class battery life on the same pack |
| Extreme conditions | Struggles in heavy rain, spray and fast fog fronts | Actively clears liquid water, not just thin fog |
Proven to integrate into existing camera architectures
- Circular optical cover windowPlaced directly in front of the camera lens aperture of a standard outdoor security camera form factor.
- Peripheral acoustic actuatorsPositioned around the rim, outside the field of view.
- Passive gravity drainageEjected water exits through the bottom of the housing.
- Clear path to enclosure-ready electronicsClearing is validated on the testbed. Shrinking the driver to fit inside standard camera enclosures, on camera battery power, is a straightforward design-in step with OEM partners.
How often would batteries need changing?
Battery cameras wake on motion. SonoFog senses the glass and clears it automatically whenever it re-fogs, from a few times a day in summer to about every 15 minutes in autumn. A continuous 1W lens heater would empty the same battery in about 22 hours, in any season.
Click a location. The chart and yearly swaps below update to match.
swaps a year with Gen 1 · +1.6 with Gen 2
- Camera only, no clearing4.3 / yr
- With SonoFog Gen 17.5 / yr (+3.2)
- With SonoFog Gen 2 (target)5.9 / yr (+1.6)
- Continuous 1W lens heater~402 / yr
How we calculate it
- Camera use per day: 400 J standby + 15 recordings × 35 J = 925 J/day.
- Clearing per day: seasons average ~46 clears/day (5 / 30 / 50 / 100) × 15 J = 694 J/day.
- Over a year: clearing adds 253,219 J. One battery holds ~79,200 J, so that is about 3.2 extra batteries.
- Gen 2 halves the energy per clear, so the extra swaps halve too.
- A 1W heater uses 86,400 J every day, more than a full battery, so it would need a swap almost daily.
Most of the extra use falls in autumn, when fog returns every ~15 minutes. In summer clearing barely touches the battery.
Estimates for a ~6,000 mAh outdoor camera battery: ~400 J/day standby, ~35 J per recorded clip, 15 J per clear (Gen 1). Gen 2 targets half the clearing energy.
Entry in outdoor machine vision, scaling to remote sensing, medical and automotive
A staged market entry: start where design cycles are short and the pain is acute, then move into regulated, high-value optics where qualification creates a lasting moat.
- PHASE 1 · ENTRYNow
Outdoor machine vision & surveillance
Battery and PoE security cameras, industrial vision, drones. No regulatory barriers, standard cover windows, and a clear battery-life pain point.
- Market size
- ~$35B
- global video surveillance market
- Ease of entry
- Fast entry · 6–12 month design cycles
- PHASE 2 · ADJACENT1–2 years
Remote sensors & high-tech gear
Weather stations, chemical process sight glasses, telecom masts and offshore monitoring. Every fogged window means a costly site visit, tower climb or process stop.
- Market size
- ~$18B
- weather stations, process monitoring & telecom masts combined
- Ease of entry
- Fast entry · industrial certification only
- PHASE 3 · PATIENT SAFETY2–3 years
Medical visualization
Laparoscopes, robotic-surgery cameras, bronchoscopes and surgical microscopes. A fogged view forces scope removal, longer anesthesia and higher risk of injury or infection.
- Market size
- ~$15B
- endoscopy & surgical visualization devices
- Ease of entry
- Moderate · medical device qualification
- PHASE 4 · SCALE3–5+ years
Automotive ADAS
All-weather clarity for exterior camera and sensor cover glass. Long qualification, but high switching costs once designed in.
- Market size
- ~$40B+
- ADAS sensor & camera market
- Ease of entry
- Long cycle · automotive qualification
Born from ultrasonics research at Aalto University
SonoFog is a research and commercialization project within Aalto University's Medical Ultrasonics Laboratory (MEDUSA) in Espoo, Finland. The clearing method grew out of years of acoustic wave research and was validated in the lab, and is now being taken towards industry.
Commercialization was funded by Business Finland's Research to Business programme together with Aalto. That stage is complete — SonoFog has moved on to paid integration pilots with camera and sensor makers.
Path to market
- 01CompletedAalto lab research
Acoustic wave research and Gen 1 benchmarks on a camera testbed.
- 02CompletedResearch to Business
Business Finland and Aalto co-funded commercialization and Gen 2 design.
- 03NowPaid OEM pilots
Paid integration pilots with camera and sensor makers.
- 04NextDesign-in & volume
Joint development, OEM modules and licensing.
Acoustic defogging, answered
How does acoustic defogging work?
Peripheral acoustic actuators send surface acoustic waves across the transparent window. The waves push and atomize droplets, mist and condensation off the optical aperture, with no wipers, moving parts or coatings.
How much energy does camera lens defogging use?
In our tests one clear used about 15 J at 1W and about 40 J at 6W. A continuous 1W lens heater uses 86,400 J a day. Because SonoFog runs only when the glass fogs, it needs a fraction of a heater's energy.
How fast is it compared to a lens heater or passive drying?
At 6W the window reached 90% clearing 18× faster than passive evaporation and was fully clear in about 8 seconds. At 1W it reached 90% clearing 6× faster.
Which optical windows can be defogged?
SonoFog is designed for rigid transparent substrates such as optical glass and sapphire windows used in outdoor cameras, machine vision, endoscopes and automotive sensors.
Can it be integrated into battery-powered or PoE cameras?
Yes. The driving electronics are designed to fit inside standard outdoor camera enclosures, and event-driven clearing keeps the energy budget small enough for battery and PoE cameras.
How do we evaluate SonoFog for our product?
Through a paid integration pilot: we fit SonoFog to your optical window, test it in your conditions and deliver speed and energy data plus an integration roadmap.
See your own camera clear itself
We fit SonoFog to your camera or sensor, test it in your conditions and hand over the data. The first step towards joint development.
Scope is tailored to your form factor, number of units and test conditions, and agreed before work starts.
- Prototype fitted to your optical window
- Clearing tests in your fog & rain conditions
- Results report: speed, energy, image quality
- Integration roadmap for your product
- 01Scope callFree, 30 min
- 02Pilot build & testPaid pilot
- 03Joint developmentDesign-in