Light behaves like a wave.
Brightness is expressed as amplitude.
Color is expressed as wavelength.
For example, light from the sun or a fluorescent lamp
vibrates in various directions.
These types of lights are called unpolarized light.
On the other hand, light vibrating in a specific direction
is called polarized light.
Unlike brightness or color,
polarization can’t be detected
by conventional image sensors or human eyes.
“Polarsens” is a new image sensor technology
for detecting polarized light.
How to create polarized light?
First, let’s see polarized light by reflection.
Depending on the reflected light angle,
the degree of polarization shows the level of polarized light.
When light is reflected at an angle of 0 degree
it will have little polarized light.
But the greater the angle,
the higher the degree of polarization.
The angle at which we can achieve the highest degree of polarization
is called “Brewster’s angle”
This varies depending on materials,
but for most it is 60 degrees.
When the light source is unpolarized,
it is important to set the camera angle at this “Brewster’s angle”
to get the optimized information.
On the other hand,
if using a Polarized light source,
then you will have far greater flexibility.
By using a polarization filter,
we can abstract polarized light.
When polarized light enters the polarization filter,
the intensity of outgoing light changes
depending on the relative angle
between the polarized direction
of incoming light and the polarizer.
“Polarsens” has multi-direction on chip polarizer.
The intensity of the light
through each polarized pixel is different.
Polarsens, can capture multi-directional
polarized images in a single frame.
The intensity of the light is converted
into an electric signal in the image sensor
and recognized as digital value.
The degree and direction of polarization
can be calculated with these values.
For example, we can easily identify
the shape of an object
or detect scratches by making use of
this polarization information.
By using the HSV color mapping,
we can easily see the direction of polarization.
Different colors represent different directions.
For example, scratched and dents
will be seen due to the difference
in the degree of polarization.