Have we solved the autofocus problem in car cameras?
The new Sharp-7 camera from Sheba Microsystems has achieved thermal stability. What does that mean for the future of assisted driving?
Sheba Microsystems claims to have developed the world’s autofocus camera for cars.
If it’s shown to work, that would be a huge leap forward for advanced driving assistance systems, and ultimately autonomous driving vehicles.
If it seems strange that an autofocus camera should be such a big deal, it’s worth investigating the science of the device.
Plenty of cameras – including the ones in our phones – have autofocus capabilities. But they’re often only used “in the moment of need.” You pull out your phone, the autofocus engages, you take a selfie, upload it to your top ten social media platforms and go about your day. The whole process takes less than thirty seconds, and your phone is then usually replaced in a familiar environment with a temperature that’s more or less constant within an acceptable level of human comfort.
That’s a whole different ball game to what an autofocus camera for cars has to endure.
In the first instance, the camera’s outdoors, always. If it isn’t outdoors, always, it’s functionally useless as a car camera.
That means if the temperature outside falls, the temperature of the camera falls. If the temperature outside soars, so does the temperature of the camera. And these are not momentary fluctuations – these temperature shifts can be significant, severe, spread over a long exposure…
And that causes problems.
Camera components expand and contract with temperature differences. What does expansion and contraction do to lenses? It de-focuses the images they produce.
Ironically, you might think that having a higher-quality camera with more pixels per inch would overcome that issue.
You would be almost magnificently wrong. More pixels per inch merely magnifies the effect.
What Sheba has done is shifted the sensor along the optical axis, and then applied micro-electromechanical systems micro-actuators, meaning the camera can micro-adjust itself to the effect of the temperature change.
In essence, the micro-actuators allow the Sharp-7 camera to balance on the high wire of image clarity, by gently adjusting itself to its conditions as necessary.
In other words, it maintains thermal stability, and so delivers consistently crisp, clear images, in anything from -40 to 302 degrees Fahrenheit, or from -40 to 150 degrees Celsius.
That means the camera could be used consistently in an ADAS rig to help increase the road safety of both drivers and vehicles.
