VISION AWARD
New camera lens design for shock and vibration resistance By Nina Kürten, Fujifilm Optical Devices Europe
I
ndustrial imaging systems are frequently subject to strong acceleration, shock, and vibration. Tis is especially true for mobile
systems, like robot-guided 3D scanners, but also for fixed installations. Such mechanical stress oſten causes a significant reduction in the resolution and a shiſt in the optical axis – a severe problem for machine vision, optical metrology applications, and optically calibrated systems. Fujifilm investigated the impact of shock and
vibration on industrial fixed focal length lenses and from this work developed a new mechanical design for lenses, the Fujinon Anti-Shock and Vibration technology. Tis technology is based on elastic fixation of the glass elements inside a lens. It minimises adhesives that are used to fix glass elements within conventional camera lenses. Adhesives are unable to withstand shock and vibration over time, causing the glass elements inside lenses to loosen and the resolution and mechanical stability to degrade. Te elastic fixation used in Anti-Shock and Vibration lenses gives a constant performance and high image quality over time. Fujifilm tested industrial fixed-length focal
lenses with, firstly, 10G shocks applied from six different directions orthogonal to the optical axis. Next, a special vibrating table exposed the
lenses to various sinusoidal vibrations according to IEC 60068-2-6 (up to 500Hz and 100m/s²). Finally, the shock test was repeated. Te tests showed that the position of
the optical axis shiſted by up to 26μm with conventional lenses. Tat corresponds to a change of approximately seven pixels for second generation Sony Pregius sensors with a pixel size of 3.45μm. Such a shiſt in the optical axis is not acceptable for calibrated systems such as 3D scanners or for metrology applications.
The test showed a
deterioration in the resolving power of conventional lenses after vibration
Te resolving power of the lenses was checked
before and aſter the test with a ‘text chart’, which gives the resolution of a lens across the entire image simultaneously by measuring the contrast of text. Te contrast measurement was transferred via a Fujifilm soſtware tool to a resolution map showing high resolution in red and low resolution in blue. Te test showed a deterioration in the resolving power of conventional lenses aſter vibration. For
The exposure measurement is asynchronously output from the sensor together with the pixel’s coordinates in the sensor array
most machine vision applications, where fast acceleration and strong vibration can occur, these lenses are not suitable. Te shiſt in optical axis is reduced
significantly in Fujinon machine vision lenses incorporating the Anti-Shock and Vibration technology. Te lenses withstood shocks showing a shiſt in optical axis of between 4μm and 10μm. Te resolving power also remained stable during and aſter the vibration test, and the resolution degradation is minimised across the entire image. Compared to conventional products, these
Anti-Shock and Vibration lenses maintain their high optical performance despite the shock and vibration that unavoidably occur in industrial imaging systems.
www.fujifilm.eu/eu/products/optical- devices/cctv-and-machine-vision
PhoXi 3D camera By Tomas Kovacovsky and Jan Zizka, Photoneo
P
hotoneo’s PhoXi 3D camera captures accurate point clouds combined with a standard intensity image. It is based
on Photoneo’s technology called Parallel Structured Light implemented on a custom CMOS image sensor. Te novel approach gives efficient, high-resolution scanning in motion. Photoneo’s Parallel Structured Light
technique projects and captures multiple encoded patterns at the same time. Tis is done by using pixel modulations inside the company’s custom CMOS sensor. Te sensor is divided into several groups of individually modulated pixels, which work synchronously with a laser light projector. Instead of modulating the projection itself, the coded patterns are injected into the groups. At the
end of the frame, the sensor can produce more than 20 different virtual images of the scene lit by the coded patterns. Te technique can use any kind of sequential structured light pattern, and can adapt to different materials and light situations. Te virtual images are then processed onboard the camera. In the ‘one-frame’ camera mode, the sensor
provides 1,068 x 800 resolution output at up to 60fps. Tese points are interpolated from around 500,000 individual measurements. Te typical standard deviation of z-noise at 1m distance is less than 0.5mm. Te sensor uses 4.5 pixels per 3D measurement with sub-pixel accuracy coding (high z-accuracy), which gives a high XYZ resolution. Te other mode of operation is a scanner
38 Imaging and Machine Vision Europe • October/November 2018
mode designed for static scenes. Here, the sensor returns its raw output of 1,602 x 1,200 individual measurements. Tis is captured in three subsequent frames. Te projection unit lights the scene with a laser deflected
@imveurope
www.imveurope.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72
