Burlington, MA--Kasalis, which supplies manufacturing systems for camera-module assembly, has completed fully functional builds of array cameras developed by Pelican Imaging (Mountain View, CA).
Intended for mobile devices, the Pelican Imaging array cameras use computational imaging, which provides depth information at every pixel. As a result, the user can focus on any subject, change focus (even on multiple subjects) in postprocessing after the photo is taken, capture linear measurements, scale and segment images, change backgrounds, and apply filters. One well-known example of a similar type of device is the Lytro camera (a full-sized camera—much larger than the Pelican Imaging device).
Six-degree-of-freedom alignment
The builds were done on Kasalis' Pixid volume-manufacturing systems. These systems provide six-degree-of-freedom active alignment for Pelican Imaging's array cameras, which is important because inherent tolerances in the lens arrays produce variations in the back focal length (BFL) of each lens in the array. Using active feedback from the image sensor, the Pixid systems can adjust the tip, tilt, and focus positions of the lens array to both optimize focus and minimize the effect of the BFL variation of the elements of the lens array.
In addition, the sixth rotation axis (yaw or theta-Z) is used to position the center of each element of the lens array to the center of each focal plane on the sensor. Passive-alignment techniques don't meet the demands of an array camera, says Kasalis. The Pelican Imaging 4x4 array camera is divided into 16 individual focal planes, and the image on each of these individual active areas needs to be analyzed over many regions of interest to optimize the focus.
The Pixid systems examine the focus in up to nine regions of interest on each focal plane. For the 16 active areas of a 4x4 array, this adds up to 144 unique regions of interest. The Pixid’s Image Signal Processing Unit (ISP) has USB 3.0 streaming, quad-core processing, and real-time operating systems, allowing high megapixel images to be streamed and processed without using preview mode or other methods that may degrade image quality, notes Kasalis. Kasalis uses Pelican Imaging’s proprietary MIPI container algorithms to reconstitute the 16 images from the sensor.
