Low-cost dynamic real-time foveated imager.

Abstract

Foveated imaging systems have the ability to capture local high-resolution or high-magnification images with wide field of view (FOV); thus, they have great potential for applications in the field of monitoring and remote sensing of unmanned aerial vehicles. Hence, foveated optical systems are in strong demand. However, the existing foveated imaging systems either are equipped with expensive modulators or require fixing the local high resolution imaging field, which is not suitable for mass production or object tracking in industrial applications. We propose a low-cost dynamic real-time foveated imaging system for extensive use in the listed applications. Specifically, we place a microlens behind the first intermediary image plane to modulate the local focal length, constructing a local high magnification imaging channel. One two-axis translation stage drives the microlens to scan in the plane perpendicular to the optical axis, resulting in dynamic local high magnifying imaging. Furthermore, the peripheral imaging channel and the foveated imaging channel focus on the same detector, and the post image fusion is unnecessary; the system consists of only a common aspherical lens and thus is very inexpensive. The experimental system has a focal length of 25mm, a full FOV of 30°, and an entrance pupil diameter of 5mm, while the local high magnifying imaging channel has a focal length of 35mm and FOV of 15°. Experiment results show that the low-cost dynamic real-time foveated imaging system performs very well.