Recent changes with the new sensor sizes and telecentric lenses for measurement applications

Transcription

1 Recent changes with the new sensor sizes and telecentric lenses for measurement applications By Raf Slotwinski Alrad Imaging division of Alrad Instruments Ltd

2 ALRAD - Company Profile ALRAD are a Distribution company for Imaging, Electronic, Photonic and Analytical Components and Instruments including: CCD, CMOS and other cameras (InGaAs, bolometer, etc.) Frame Grabbers and Digital Acquisition Cards LED and Laser Lighting for Machine Vision Imaging and Image Processing Software Optics, Lenses Linear and Area Sensors Trading since 1970, 44 years in business. Three divisions Imaging, Photonics and Electronics

3 Historic sensor formats and resolutions Analogue interline CCD sensors around Y2000 were mainly interlaced designs: EIA/NTSC or CCIR/PAL, with either 350TVL (std) or 570TVL (high) resolution. This was followed by introduction of progressive scan sensors with digital interfaces: 1/4in VGA 1/3in VGA XGA SXGA 1/2in VGA SXGA 1/1.8in UXGA 2/3in SXGA QXGA

4 Sensor size format or type Format Type Aspect Ratio Ø Dia. (mm) CCD/CMOS Sensor sizes* (mm) Diagonal mm Width mm Height mm 1/10" 4: /8" 4: /6" 4: /4" 4: /3.6" 4: /3.2" 4: /3" 4: /2.7" 4: /2.5" 4: /2.3" 4: /2" 4: /1.8" 4: /1.7" 4: /1.6" 4: /3" 4: " 4: /3" 4: " 3: mm Film 3:2 n/a Camera Tube CCD or CMOS Face view of a Camera Pick-Up Vacuum Tube Sensor, with a CCD superimposed on the imaging face, to illustrate the correlation of Imperial Format Types. Note: Typical sizes for camera tubes were: ½, 2/3 & 1 diameter.

5 Common Video CCD Sensors 4:3

6 Common Photographic Sensor Sizes

7 Image Circle and Image Sensor The Image Circle is the circular area where the image is produced by the lens at the focal plane. For an Area Scan sensor, the required image circle should match or exceed the sensor diagonal, irrespective of the sensor ratio, 16:9, 4:3, 3:2 or 1:1. It can be calculated very easily using the Pythagorean formula (right-angled triangle): For a Line Scan camera, the required image circle diameter corresponds to the length of the sensor.

8 Image Circle and Image Sensor In general, it is advisable to use a larger than the minimum image circle, as the optical errors tend to increase significantly from the centre of the image towards the image margin. However, some lenses are optimised for specific pixel pitch and should match closely the specifications of the sensor. The image circle that is too small for a given sensor will produce vignetting:

9 CMOSIS CMOS sensors

10 t New Sony CMOS Exmor 16:9 sensors

11 j New Sony CMOS sensors

12 New Sony CCD Sensors

13 j New e2v CMOS sensors

14 New AnaFocus / e2v sensor

15 CCD & CMOS Full Frame Format Cameras CCD: 5fps CMOS: 168fps CMOS: 30fps

16 Telecentric Lenses for Machine Vision These lenses are used mainly for highly accurate measuring applications, often used as a high magnification macro lens if small dimensions are required. VST offer a wide range of telecentric lenses, mainly small to medium diameter, fixed iris, with axial illumination option

17 Lenses for Machine Vision One object different perspectives to image entocentric perspective centre is in front of object nearer objects are larger, distant objects are smaller objective telecentric perspective centre is at infinity nearer and farther are the same size objective hypercentric perspective centre is behind the object nearer objects are smaller, farther objects are larger objective

18 Telecentric Lenses for Machine Vision entocentric telecentric telecentric measu- telecentric wide imaging accessories objectives microscopes rement objectives field objectives and -objectives

19 Telecentric Lenses for Machine Vision Telecentric optics: Influence of the optics on the image produced Distorted and distor- Strong perspective / Perspective and reflections / tion free image perspective-free image without both.

20 Telecentric Lenses for Machine Vision vicotar telecentric wide field objectives application inspection of 85 mm deep car catalytic converter with approx. 10,000 channels (0.8 mm); left: with entocentric lens, right: with telecentric lens Due to the lightweight construction with plastic lenses telecentric wide field objectives can also be used in industrial environment.

21 Lenses for Machine Vision Telecentric Lenses OptoEngineering is a optics company specialising in Telecentric Lenses and Systems, as well as other specialist optics. Their bi-telecentric range covers a wide range of sensor compatibility (up to 2/3 format) with high resolution an low distortion. back to systems end

22 Lenses for Machine Vision Telecentric Lenses Some measurement applications using Telecentric Lenses back to systems end

23 Bi-Telecentric Optical Bench

24 Some of the Industries & Applications Automotive Electronic / PCB Metals Welding Dental Food Transportation Wood

25 Trends in Imaging Technologies Higher resolution sensors VGA for speed 1.2MP main digital level, up to 29MP Improved CMOS sensors global shutter, large area, sensitivity, scmos Faster interfaces USB3, 10GigE Vision, CoaXPress, CLHS New Sensors for industrial applications InGaAs for NIR, Bolometer for LWIR (thermal) Improvements & new developments in optics resolution (>10MP), design (telecentric & custom) Improvements in Lighting technology High Intensity LEDs, new designs

26 THE END Thank you for your attention and please feel free to ask any questions OR Visit our Stand C21