machine vision lenses Archives - 1stVision Inc.

January 24, 2024March 8, 2024

TCSE series hi-res telecentric lenses

Opto Engineering is known and respected for high-performance lenses in machine vision, medical, and related fields. The new TCSE series are telecentric lenses designed for large sensor formats (4/3″, APS-C, APS-H). Each provides high resolution with low distortion.

Who needs a telecentric lens?

Before inviting you to some of the TCSE series features, let’s offer readers who aren’t already telecentric-savvy a brief motivation for this category of lens. If you are doing precise gauging applications – measuring via optics and software – your tolerances may require a telecentric lens. A telecentric lens eliminates perspective error. They have very low distortion. And, if paired with collimated light, they enhance edge definition.

For a comprehensive read, check out our blog Advantages of Telecentric Lenses in Machine Vision Applications. Not sure if you need a telecentric lens? Call us at 978-474-0044 – tell us a little about your application and we can guide you through any or all of lens, camera, lighting and other choices.

TCSE5EM065-J – Courtesy Opto Engineering

TCSE lenses are available for applications using light in either the visible spectrum or near-infrared (NIR) wavelengths. Currently there are 8 members in the TCSE product family.

Image circle diameter

The TCSE Series offers image circle diameter options from 24 – 45mm.

Magnification

A key parameter in telecentric imaging is the level of magnification available. The 8 members of the TCSE Series offer magnification ranging from 0.36 through 2.75 times the original object size.

Working distance

The working distance (WD), from the front of the lens to the object being imaged, varies by lens model across the TCSE Series. The shortest WD offered is 160mm, spanning distances up to 240mm. These long working distances allow space for lighting and/or robotic arms.

Worth noting

While typically “plug and play” once mounted on your camera, it’s worth noting that the TCSE lenses offer back focal length adjustment, should one choose to fine tune.

Summary

Telecentric lenses are the core business for Opto Engineering, who have more than 20 years expertise in research, development, and production. 1stVision, North America’s largest stocking distributor, works to understand each customer’s application requirements, to help you select the ideal lens, camera, or other imaging component(s). Call us at 978-474-0044.

1st Vision’s sales engineers have over 100 years of combined experience to assist in your camera and components selection. With a large portfolio of lenses, cables, NIC cards and industrial computers, we can provide a full vision solution!

January 14, 2020January 14, 2020

Which machine vision lens provide ultra-high resolution?

The image fidelity achievable from a machine vision camera is only as good as the optics you use! Many of the machine vision cameras used today utilize very small pixels, down to 1.25um. The crispness of the images are a result of the resolution of your machine vision lens, so matching the right lens to the camera sensor is extremely important. We classify the lens resolution in terms of line pairs per millimeter (lp/mm). So, what lenses can help resolve these small pixels?

pixel size — Click to download our quick reference chart

First, the relationship of pixel pitch can be put in terms of lp/mm as seen in the chart to the right. Machine vision lens manufacturers today typically provide the resolving power on their data sheets to help in the lens selection and ensure your matching the lens to the image sensor. If not matched properly, image contrast will suffer.

For machine vision cameras with small pixels, the Moritex ML-M-UR “Ultra high” resolution lenses are an excellent choice with the capability of resolving pixel pitches down to 2.2um with good contrast.

Click HERE for specifications on the Moritex ML-M-UR series and request a quote

The comparison images below show the Moritex ML-M-UR series compared to a conventional lens with less resolution. As you can see in the cutout of the corner, the contrast is much higher with lenses with high resolving power.

machine vision lenses - image comparison — Left (High resolution lens) Right (Legacy lower resolution lens)

Lens resolution typically has fall off to the edges of a lens. To maintain high contrast, Moritex has optimized the ML-M-UR series to have good resolving power to the edges of the lens.

The charts below represent the contrast (MTF) corresponding to image height (x-axis ) showing the contrast from lens center to lens edge. The X-axis represents the center starting at zero millimeters and mapping MTF to the edge (furthest right point) The ML-M-UR shown in the left chart demonstrates very good performance across the lens. (A relatively flat line is good!) As a comparison to another lens (right chart), contrast is degraded across the lens from center to edge.

Aside from high resolution, The Moritex ML-M-UR series are a compact, 29mm diameter design and well suited for typical 29mm cube cameras. Additionally the lenses have an anti-vibration design with maximum acceleration to 10G’s.

Click to contact — Give us some brief idea of your application and we will contact you to
discuss camera options.

1st Vision’s sales engineers have over 100 years of combined experience to assist in your camera selection. With a large portfolio of lenses, cables, NIC card and industrial computers, we can provide a full vision solution!

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

Optotune liquid lenses – 5 case examples for machine vision

Liquid lens technology, with its ability to change focus within the order of milliseconds is opening up a host of new applications in both machine vision and the life sciences. It is gaining growing interest from a wide cross section of applications and easily adapts to standard machine vision lenses.

Liquid lens technology alone provides nice solutions, but when combined with advanced controls, many more applications can be solved.

To learn the fundamentals of liquid lens technology and download a comprehensive white paper read our previous blog HERE.

In this blog, we will highlight several case application areas for liquid lens technology.

Case 1: Applications requiring various focus points and extended depth of field: This does cover many applications, such as logistics, packaging and code reading in packaging. Optotune Liquid lenses provide the ability to have pre-set focus points, auto-focus or utilize distance sensors for feedback to the lens. In the example below, 2 presets can be programmed and toggled to read 2D codes at various heights essentially extending the depth of field.

Case 2: 3D imagery of transparent materials / Hyperfocal (Extended DOF Images: When using an Optotune liquid lens in conjunction with a Gardasoft TR-CL180 controller, sequence of images can be taken with the focus point stepped between each image. This technique is known as focus stacking. This will build up a 3D image of transparent environments such as cell tissue or liquid for analysis. This can also be used to find particles suspended in liquids.

A Z-stack of images can also be used to extract 3D data (depth of focus) and compute a hyper-focus or extended depth of field (EFOF) image.

The EDOF technique requires tacking a stack of individual well focused images which have preferably been synchronized with one flash per image. An example is show below with the rendered hyper focus image shown at right.

Case 3: Lens inspection: Liquid lenses can be used to inspect lenses, such as those in cell phones for dust and scratches looking through the lens stack.

For this application, a liquid lens is used in conjunction with a telescentric lens taking images through different heights of the lens stack.

Case 4: Bottle / Container inspection: Optotune Liquid lenses can be used to facilitate image bottom’s of glass bottles or containers of various heights.

In this example, the camera is consistently at the neck of the bottle, but the bottom is at different heights.

Case 5: Large surface inspections with variation in height: Items ranging from PCB’s to LCD’s are not flat, have various component heights and need to be inspected at high magnification (typically using lenses with minimal DOF). Optotune Liquid lenses are a perfect solution using preset focus points.

Machine Vision applications using Optotune Liquid lenses and controller are endless!

These applications are just the tip of the iceberg and many more exist, but this will give you a good idea of capabilities. Gardasoft TR-CL controllers are fully GigE Vision compliant, so any compatible GigE Vision client image processing software such as Cognex VisionPro, Teledyne Dalsa Sherlock or National Instruments LABVIEW can be used easily.

Contact us to help in the specification and providing pricing

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

What are the f-numbers on machine vision camera lenses? f-stop explained!

Why does 1stVision focus (no pun intended) so much on machine vision lenses. As the old saying goes, if you have garbage in, you get garbage out.

The lens is the input to the machine vision system. A low quality lens means that you have already degraded the image coming into the sensor. For instance, let’s say you chose a camera with 5um pixels, which equates to a lens being able to resolve 100 lp/mm. If your lens’ Modular Transform Function (MTF) is only 50 lp/mm, you should have chosen a camera with 10um pixel size, because the lens can’t do any better than that. As a note, don’t infer that a camera with 10um pixels is worse than a camera with 5umpixels from this example, as that is not true. Learn more on MTF here

A machine vision lens gathers light and then focuses it. When we talk about focus, we are talking about the MTF, but when we discuss light gathering properties, we need to discuss the lens f-number.

FUJI -f-stop — FUJI lens showing f-stops

f-number
The f-number is defined as the ratio of the focal length by the aperture width (diameter of the entrance pupil). So a 50mm focal length lens with a f-number of 2 has a 25mm entrance pupil. The lower the f-number, the more light will be allowed into the system, however this equates to more expensive lens as you need more glass to make a wider entrance pupil.

f-stop
Many camera lenses have an adjustable iris that opens and closes at the front of the lens to limit the amount of light coming in. When open all the way, the f-stop is the f-number. From there, each f-stop from wide open halves the amount of light, which corresponds to reducing the size of the aperture by 1/sqrt(2) or about 0.707 and in turn halving the area.

The f-stop is represented by a sequence of these numbers below, each letting in half the light.

Sequence: f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, f/64, f/90, f/128

The sequence is obtained by approximating the geometric sequence

Characteristics of the f-stop

Most lenses are designed to be optimal in the F4-F5.6 range, in which they have the best MTF.
The higher f-number (ie f/8 ) is, or the more closed the aperture is, better the depth of field if achieved
The lower the f-number (ie f/1.4) is, or the aperature being wide open is where you get the least depth of field, but not great MTF.

In a practical application, you need to trade off exposure time, depth of field, and available machine vision lighting. These three variables are always in tension. If you need fast exposure AND depth of field this means very small amounts of light gets to the sensor. If you need high contrast images in this situation, something has to change. Either get more light, accept less depth of field, or have some image blur.

For a full listing of machine vision lenses, click here and use the filter to help in your selection.

Related Blog posts

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Demystifying Lens performance specifications

Information courteous of Wikipedia