Vision systems require suitable lenses. Applications like Autonomous Mobile Robots (AMRs), bin picking, and stereo vision utilize wide angle lenses. Traditionally, only fisheye lenses captured ultra-wide fields of view, but they suffer from barrel distortion, reducing edge resolution and limiting applications. For this problem, there is now an efficient solution: rectilinear lenses.

Wide angle lenses take two approaches to representing the 3D world on a 2D plane:

• Equal angular slices: Each pixel captures an equal angle, leading to barrel distortion (fisheye lens).
• Equal planar distances: Each pixel images an equal distance, producing a rectilinear lens.

Rectilinear lenses maintain straight lines, though parallel lines may appear to converge (key-stoning). This is useful when imaging objects perpendicular to the optical axis, such as LCD screens for defect detection. Unlike fisheye lenses, rectilinear lenses ensure uniform pixel coverage, preserving accuracy.

A rectilinear lens effect is 3D stretching at image edges, where objects appear elongated due to flattening along the tangent angle. The wider the field of view, the more pronounced this effect. This effect increases edge resolution compared to fisheye lenses, benefiting object detection and positioning—critical for situational awareness and navigation in applications requiring real-time localization and mapping.
 

Optical Distortion

Traditional wide angle lenses (over 80-degree fields of view) exhibit curved barrel distortion due to equal angular imaging, resulting in compressed images, reduced resolution, and loss of detail at image edges. Once lost, this information cannot be recovered with software.

Software correction can convert fisheye images into rectilinear ones, but this introduces processing delays, problematic for real-time applications like AMR navigation, robotics and automation. A rectilinear lens eliminates this latency by optically correcting barrel distortion in the lens design, requiring no software intervention.

Technological Innovation

Theia Technologies' patented Linear Optical Technology addresses ultra-wide-angle imaging challenges. This technology enables rectilinear, low-distortion lenses with up to 135-degree horizontal fields of view across various image sensor formats. These lenses offer minimal working distances as low as 10cm ideal for short range inspection, up to 200lp/mm resolution performance, Near-Infrared (NIR) correction, ensuring consistent resolution from 435 – 940nm for multi-spectral use.
 

Applications

Many industries benefit from ultra-wide, no-distortion lenses. For machine vision, robotics, and automation, rectilinear lenses can enhance object position mapping, increasing situational awareness for AMRs and UAVs. Their ultra-wide, undistorted view improves obstacle detection and navigation efficiency. Rectilinear lenses enable close focus and wide coverage in pick-and-place applications, preventing work surface blind spots. Rectilinear lenses allow real-time object tracking without latency from fisheye distortion correction, improving timing and accuracy in robotics. Increased edge resolution supports large-area inspection at close distances, such as package identification and damage detection. Ultra-wide no distortion lenses provide high-resolution monitoring for remote pipelines, eliminating the need for multiple cameras. Lastly, Rectilinear lenses improve human motion analysis with a portable setup, simplifying calibration by removing image de-warping before stitching.
 

Conclusion

Modern vision systems require high-performance, wide angle lenses for real-time, high-resolution imaging. Fisheye lenses introduce barrel distortion, compressing images and requiring software correction, causing latency. Rectilinear lenses correct distortion optically, eliminating software delays and preserving resolution—an elegant, efficient solution.