In September, Sony launched the IMX250MZR sensor to integrate polarisation functionality at the pixel level. The sensor can filter light in 4 planes with pixels assigned a plane in a 2×2 calculation unit. In a unique move, Sony Image Sensing Solutions division has developed both hardware and software offerings, with a IMX250MZR software development kit. Sony says this will cut development time from several months to weeks.
Stéphane Clauss gives Electronics a more in-depth look at the technology.
SDK Overview
It’s been a number of years since the R&D and market development phases of Sony’s first polarised camera module – the XCG-CP510 – began. In this time, from talking with selected key players of targeted markets, it became clear that the biggest barrier to adoption was the ability of system developers to work with the new sensor technology easily.
As a result, Sony has for the first time developed a dedicated image processing library to speed solution development: taking it from between 6-24 months, depending on your team, to c. 6-12 weeks. This approach brings together a set of key functions – such as stress measurement or glare reduction – with highly optimised algorithms. The set of functions have been developed to run on a standard PC, with the choice of CPU / GPU architecture being dictated by the processing functions, as well as its resolution and frame rate. The SDK launch is timed to match Sony’s polarised camera going into production at the end of November.
Key features
Support functions are the first level supplied in the SDK, including demosaic and raw extraction. The ‘Cosine fit’ allows the developer to define a virtual polariser angle for the whole image and the ‘average’ function creates a non-polarised image from the raw data, to simultaneously export what a standard machine vision camera would see for comparison. Pre-processing functions calculate various polarisation specific information like the ‘degree of polarisation’, ‘Stokkes vector’ and the ‘surface normal vector’. At the higher-end level, applications-oriented functions have been implemented to manage reflections and measure stress. These functions’ algorithms have been optimised for accuracy and high computing to enable its use in real-time inspection.
Applications
The use of polarised camera modules will prove vital in a wide range of applications. The SDK has developed models for the major subset of these, with key ones listed below:
Weakness detection
In stress monitoring, we can measure where stresses are occurring by how the light bends to highlight potential weaknesses, vital in industries such as glass, PET and phone displays.
Inspection – for manufacturing / ITS
Similarly, we’ve developed models to extract reflections on an object under inspection caused by unmanaged lighting. This reflection/glare management control will not only improve quality inspection for PCB inspection and packaging (particularly in the pharmaceutical industry); but for traffic monitoring, allowing you to confirm the driver or see if a mobile device is in use, a passenger isn’t strapped in, or if only one driver is in the 2+lane.
Scratch identification
For transparent goods inspection, the camera and SDK make it feasible, with the reflection enhancement, to more easily undertake surface inspection and scratch detection.
For the above, we have already developed and validated the software, in a collaboration between Sony and customers, to implement the applications listed above and we’re discovering new usages every day.
For more information on Sony’s SDK, click here.
