Posts

Posted on

Advantages of Telecentric lenses in machine vision applications

Telecentric lenses are essential in eliminating distortion errors caused by standard lenses in machine vision applications.  


Telecentric lenses are defined by lenses only accepting incoming light ray bundles whose principal rays are parallel to the optical axis of the lens as seen in the diagram below

 




















Key advantages to a Telecentric lens are constant magnification, no perspective error and very low distortion

 









 



How do the advantages of telecentric lenses help in machine vision applications?  

Constant Magnification

Telecentric lenses can provide constant magnification, and not influenced by varying lens to object distances.  



Example: The image to the right shows 2 screws in which the 2nd screw is 10mm further away from screw 1 when viewed from the Telecentric lens in the setup.












Using a standard lens, screw #1 which is closer will appear to be larger














Using a Telecentric lens, the screws look the same size and not influenced by the lens to object distance.  

This is very helpful in applications to ensure accurate measurements negating any deviations from part placement.

Perspective Error

Standard lenses show significant perspective errors, whereas telecentric lenses are able to eliminate any perspective effects.  In cases where measurements are critical, using a telecentric lens is a must!




Low Distortion

Regular lenses have 1-2% distortion, whereas telecentric lenses have 0.1%





Regular lens will either have “Barrel” (left image) or “Pin cusion” distortion (right image) 






    Barrel Distortion                   Pin Cushion Distortion

In barrel distortion, image magnification decreases with distance from the optical axis. This is common in fish-eye lenses.  

In pincushion distortion, image magnification increases with the distance from the optical axis.  

Using telecentric lenses in machine vision applications will eliminate barrel and pin cusion distortion.  Low distortion is imperative where accuracy is required.  

How can it get any better!  – Use Collimated light!

Telecentric lenses provide a high level of accuracy, but when coupled with a collimated light source, edge definition is increased.

Diffused backlights can generate unwanted border effects and create a “fake” image of the edge of a part.  Collimated backlights allow only parallel rays to pass by objects.  This setup would be setup like the diagram below.  

   
The result is very crisp edge definition as seen in the images below.  The left image is using a standard backlight in which light “wraps” around the cap.  The right images use a collimated back light providing excellent edge definition.










 

Images courteously of Opto Engineering!1st Vision has extensive knowledge in industrial imaging and can help answer any questions.  We have over 100 years of combined knowledge and look forward to discussing your application.  Please do not hesitate to Contact us!  1st Vision can provide a complete solution including cameras, lenses, lighting and cables.  

Ph:  978-474-0044
info@1stvision.com
www.1stvision.com  

Follow us on Social Media!

    https://www.facebook.com/pages/1st-Vision/944658058935262?fref=ts           

Posted on

Grade 1 image sensors provide a performance gain over Grade 2 image sensors! Learn how this effects your cameras quality.

 

When image fidelity is of high importance, seeking out cameras with a better “Grade” image sensor is required.

BUT.. What does this mean?  
What defines the “Grade” of an image sensor?

ON-Semiconductors (Formerly Kodak) is one of the few sensor manufacturers that provide options in sensor grades.  Camera manufacturers can typically select a Grade 1 or Grade 2 sensor for their camera designs.  All image sensors have some amount of defective pixels.  The number of defects determines the quality grade and the value of the image sensors.  Most camera manufacturers select Grade 2 due to lower cost sacrificing image performance except a select few.  



Defective pixels can either be dark, as they don’t collect any light, OR be bright (hot pixel), as they are always outputting a signal.  


An example of a “Hot Pixel” is shown to the right


Defective pixels, in turn can result in incorrect processing of an image!

In most all cases, cameras are corrected at the factory prior to shipment and found in the “defect map” that is stored in the camera.    

Under challenging conditions or high temperature environments, additional defective pixels may appear.  These can be corrected using a custom defect map. 

Defect pixel correction suppresses pixels or clusters and reconstructs the expected value by interpolating the neighboring pixels.  Standard algorithms use the pixel to the left or to the right of the defect pixel for the interpolation, however more advanced algorithms can be used.  

Image Sensors from ON-SEMI are graded per the number of defects within the sensor.  This encompasses bright and dark pixel defects along with cluster defects.  

Below is an example from the ON-Semiconductor 29MP KAI-29050 sensor defect description.   

** Chart is courtesy of ON-Semiconductor KAI-29050 specification 


Need additional help in making decisions on selecting a high resolution camera?  Visit our High Resolution camera page

1st Vision has extensive knowledge in industrial imaging and can help answer any questions.  We have over 100 years of combined knowledge and look forward to discussing your application.  

Please do not hesitate to Contact us!  1st Vision can provide a complete solution including cameras, lenses, lighting and cables.  

Ph:  978-474-0044
info@1stvision.com
www.1stvision.com  

Follow us on Social Media!

    https://www.facebook.com/pages/1st-Vision/944658058935262?fref=ts           

Posted on

71 MP Machine Vision USB3 cameras are now affordable!

The Crowley Company introduces the first affordable 71 megapixel machine vision camera using the CMOSIS CHR70M image sensor, the MACHCAM 71

The MACHCAM 71 is designed with machine vision in mind, bringing ultra high resolution together in a small case and USB3.0 interface

With a resolution of 10000 (H)  x 7096 (V) at 3 frame per second, this machine vision camera provides incredible resolution at an attractive price.   Contact us for a quote

Well suited to solve applications in various industries including: 

  • LCD / PCB Inspection
  • Aerial Imaging
  • Scientific Imaging
  • Medical Imaging
  • Aeronautics
  • Packaging and Inspection
  • Transportation

Features include:

  • 71 MP CMOS sensor (3.1um pixels) @ 3 fps (full resolution)
  • Compact size for large 71 MP sensor
  • USB3  Interface
  • Extended Temperature range  (-30 to +70 deg C )
  • Full Software Development Kit (SDK)
  • Internal trigger mode
  • F-mount standard
  • Color and Monochrome variants


That is a lot of pixels!!!   What’s that mean for an application in terms of pixels on a feature?  Download our whitepaper on calculating resolution which contains a helpful calculator.  

Questions?    –   1st Vision has extensive knowledge in industrial imaging and can help answer any questions.  We have over 100 years of combined knowledge and look forward to discussing your application.  

Please do not hesitate to Contact us!  1st Vision can provide a complete solution including cameras, lenses, lighting and cables.  


Ph:  978-474-0044
info@1stvision.com
www.1stvision.com  

Follow us on Social Media!

    https://www.facebook.com/pages/1st-Vision/944658058935262?fref=ts           

Posted on

New 5-megapixel Sony IMX250 & IMX264 models added to JAI’s GO Series of CMOS cameras

The GO-5100-PGE is a new 5-megapixel camera available in monochrome and Bayer color models built around the Sony PregiusTMIMX250 CMOS sensor. 
 
The GO-5101-PGE delivers the same 5-megapixel resolution using the Sony PregiusTM IMX264 CMOS sensor. It too offers a choice of monochrome or Bayer color models.
These new GO Series cameras feature small, 3.45-micron square pixels, enabling the full resolution (2464 x 2056 pixels) to fit within a standard 2/3-inch C-mount optical format. This gives users a wider range of lens options than 5-megapixel cameras with typical 1” optical formats, and also makes these cameras ideal replacements for customers using older CCD cameras built around Sony’s ICX625 sensors, which have an identical pixel size and optical format.
Both the GO-5100-PGE and the GO-5101-PGE run at 22.7 fps in full, 8-bit resolution. 10-bit and 12-bit modes are selectable at reduced frame rates. The cameras let users define a region-of-interest from within the full resolution, which can then be output at a faster frame rate. Similarly, on monochrome models, 1×2, 2×1, and 2×2 binning is available for both added sensitivity and faster frame rates at reduced overall resolution. 
As part of JAI’s popular GO Series, the GO-5100-PGE and GO-5101-PGE feature a small form factor (29 mm x 29 mm x 41.5 mm, excluding lens mount) and weigh only 46 grams – among the lightest cameras available at this resolution. More importantly, the cameras carry the same industrial-grade specifications as other Go Series models to ensure performance in factory environments. These include an 80G shock rating, 10G vibration rating, a standard operating temperature range of -5°C to +45°C, and an overall MTBF rating of more than 200,000 hours.
   
Standard features include a high-performance global shutter with speeds as fast as 14 µs (in 8-bit mode), pixel blemish compensation and shading correction functions, a built-in 256-point look-up table for gamma customization, and JAI’s Auto Level Control (ALC) feature that combines auto gain and auto shutter capabilities into an integrated function to let users optimize their auto exposure control for lowest noise, fastest shutter, or other priorities.
A multi-ROI mode is included on the GO-5100-PGE models to allow users to define from 2 to 64 sub-regions within a single frame. This lets users maintain a wide field of view while reducing the amount of data being read out of the camera and increasing the overall frame rate.
1st Vision has extensive knowledge in industrial imaging and can help answer any questions.  We have over 100 years of combined knowledge and look forward to discussing your application.  

Please do not hesitate to Contact us!  1st Vision can provide a complete solution including cameras, lenses, lighting and cables.  

Ph:  978-474-0044
info@1stvision.com
www.1stvision.com  

Follow us on Social Media!

    https://www.facebook.com/pages/1st-Vision/944658058935262?fref=ts