Super wide-angle lenses and fisheye lenses have pronounced barrel distortion. When viewing a flat object, off-axis features are “squeezed” significantly relative to the on-axis ones. This reduces the effective off-axis resolutions. For many applications, it is an undesirable effect. It is possible to post-processing the image to reduce this effect. However, post-processing in software reduces the image quality because the missing off-axis information must now be interpolated.
We created a new class of super wide-angle and fisheye designs using high precision aspherical elements to reduce the off-axis “squeezing” optically. Comparing with standard f-theta designs, the distortion reduction is on the order of 50%. This allows off-axis objects to be imaged with more pixels. This technology has brought significant commercial benefits to security and automotive back-up cameras.
Tailored Distortion® is an innovation from Sunex to manipulate the distortion to achieve the best image quality in accordance with a client’s requirements:
- Edge Enhanced for fisheye lenses
- Fovea profile for forward ADAS
- Custom profile
Tailored Distortion® is used to achieve the following:
- Increase the angular resolution in a specific region of interest
- Minimize or eliminate the use of electronic distortion correction
- Improve the image quality when electronic distortion correction is employed
- Manipulate the HFOV with respect to the VFOV
The below graphic compares a fisheye lens with standard distortion (on the left) with a Sunex Tailored Distortiontion™ lens (on the right). One can observe three key differences:
- Tailored Distortiontion™ offers more vertical pixels (here 8 compared to 5 squares) while maintaining the same horizontal resolution
- Pixels in the center (blue color) are less blown-up for a Tailored Distortiontion™ lens
- Pixels at the edge (yellow color) are less squeezed for a Tailored Distortiontion™ lens
A further advantage of Tailored Distortion is that it provides a more rectilinear image. The result is an image that maintains a more realistic perspective that is much less disorienting than traditional fisheye images. This means that many applications, such as automotive surround view, doorbell phones or 360º surveillance may not require any software dewarping at all. And since Tailored Distortion is all done optically, there is no software manipulation of the actual image, thus avoiding many of the issues sometimes associated with post-processing.
Like a traditional fisheye lens, Tailored Distortiontion™ is ideal for automotive, security, and medical applications where an ultra-wide field of view is required. Please view our webinar to learn more about Sunex Tailored Distortiontion™.
Please view this link for a list of Sunex Super Fisheye and Tailored Distortion(R) lenses: http://www.optics-online.com/dsl_fisheye.asp