Tailored Distortion® Lenses

Sunex is pleased to introduce a new type of digital imaging lens that features optical distortion tailored to optimize camera performance.  The Tailored Distortion™ lens is ideal for any application using a wide-angle field of view camera, such as security cameras and automotive rear view cameras.

Optical distortion is an aberration that makes straight lines appear curved in the image.  Typically, the greater the field of view the greater the distortion, and the more curved straight lines appear.  A familiar example is the image formed by a fisheye lens.  The Tailored Distortion™ lens significantly reduces the distortion by optically “stretching” the information at the edge of the image. 

Reducing the distortion by optically stretching the information at the edge of the image has many benefits.  The optical distortion is drastically reduced.  Lines that appear very curved in a standard fisheye image will be significantly less curved with the Tailored Distortion™ lens.  Shapes appear more normal.  The result is a more acceptable and pleasing image. 

For automotive rear view cameras, wide-angle lenses are used to capture a wide field of view behind the vehicles.  If a fisheye lens is used, the off-axis objects are distorted and “squeezed” (see Figure 1A).   With a Tailored Distortion™ lens, the off-axis objects are less distorted and more visible to the driver (see Figure 1B).

Figure 1A. Rear view camera with a standard wide-angle lens	Fig 1B. Rear view camera with a Tailored Distortion lens

Another example is a security camera mounted in the ceiling: the entrances and exits from the room will be along the edge of the image.  With Tailored Distortion™ the entrances and exits are optically stretched resulting in more image sensor pixels devoted to this region of interest.  Compare the Tailored Distortion image (Figure 2B.) with the standard fisheye (Figure 2A).  With Tailored Distortion™ the entrances and exits appear stretched, details are easier to see.

A Tailored Distortion™ lens offers other benefits. In a typical application the image is captured and then dewarped by a digital signal processor (DSP).  Dewarping an image requires significant processing power from a DSP.  The Tailored Distortion™ lens eliminates or minimizes the processing required to dewarp the image.  Eliminating or minimizing the processor overhead devoted to de-warping can also decrease the amount of time delay between capturing and displaying an image, bringing the display closer to real-time. 

Reducing the distortion optically may also reduce the cost to develop software and implement these features into a camera.  And only a Tailored Distortion™ lens can increase the resolution in the area of interest.  Figure 3 is a simulated comparison between a standard fisheye lens and a tailored distortion lens both having 130 degree horizontal field of view. 

Figure 3 Comparison of a tailored distortion lens and a fisheye lens with 130 deg HFOV

Sunex has also developed proprietary de-warping software to enhance images taken with Tailored Distortion lenses. For more information about fisheye lenses with Tailored Distortion™ and de-warping software,  please contact Sunex Optical Sales Engineers at +1 760 602 0988.  Or visit the Sunex website at www.sunex.com.