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Spatial resolution is an essential machine vision concept

Spatial resolution is determined by the number of pixels in a CMOS or CCD sensor array.  While generally speaking “more is better”, what really matters is slightly more complex than that.  One needs to know enough about the dimensions and characteristics of the real-world scene at which a camera is directed; and one must know about the smallest feature(s) to be detected.

Choosing the right sensor requires understanding spatial resolution

The sensor-coverage fit of a lens is also relevant.  As is the optical quality of the lens.  Lighting also impacts the quality of the image. Yada yada.

But independent of lens and lighting, a key guideline is that each minimal real-world feature to be detected should appear in a 3×3 pixel grid in the image.  So if the real-world scene is X by Y meters, and the smallest feature to be detected is A by B centimeters, assuming the lens is matched to the sensor and the scene, it’s just a math problem to determine the number of pixels required on the sensor.

There is a comprehensive treatment how to calculate resolution in this short article, including a link there to a resolution calculator. Understanding these concepts will help you to design an imaging system that has enough capacity to solve your application, while not over-engineering a solution – enough is enough.

Finally, the above guideline is for monochrome imaging, which to the surprise of newcomers to the field of machine vision, is often more better than color, for effective and cost-efficient outcomes.  Certainly some applications are dependent upon color.  The guideline for color imaging is that the minimal feature should occupy a 6×6 pixel grid.

If you’d like someone to double-check your calculations, or to prepare the calculations for you, and to recommend sensor, camera and optics, and/or software, the sales engineers at 1stVision have the expertise to support you. Give us some brief idea of your application and we will contact you to discuss camera options.

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1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

About Us | 1stVision

1st Vision is the most experienced distributor in the U.S. of machine vision cameras, lenses, frame grabbers, cables, lighting, and software in the industry.

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What can multifield linescan imaging do for me?

Multifield imaging is a new imaging technology that enables capturing multiple images simultaneously at various lighting conditions e.g. brightfield, darkfield, and backlight in a single scan. It’s a variation on the concept of sequence modes. Teledyne Dalsa Linea HS is the industry’s first TDI camera capable of capturing up to three images using light sources at different wavelengths.

OK, cool.  How does that help me?  How does it differ from other imaging methods?  What applications can it solve that couldn’t be tackled before?

Backlight, Darkfield, and Brightfield images of same target

Perhaps a quick review of area scan imaging and conventional linescan imaging will help set the stage:

Area scan cameras are most intuitive, creating in one exposure a rectangular array of pixels corresponding to an entire scene or field of view.T hat’s ideal for many types of machine vision imaging, if the target fits wholly in the field of view, and if the lighting, lens, and image processing can best achieve the desired outcome at an optimal price point.

But linescan imaging is sometimes a better choice, especially for continuous-flow applications, where there is no discrete start and end point, in one dimension.  Linescan systems can capture an image “slice” that is enough pixels wide to make effective imaging computations, and, where required, to archive those images, using fewer active pixels and reducing sensor costs compared to area scan.  Other benefits include high sensitivity and the ability to image fast moving materials without the need for expensive strobe lighting.

Understanding line scan applications: concepts still relevant!

… so much for the review session.  So, what can multifield linescan imaging do for me?  Multifield capable linescan cameras bring all the benefits of conventional linescan imaging, but additionally deliver the perspectives of monochrome, HDR, color/multispectral (NIR), and polarization views.   This can enable machine vision solutions not previously possible, or solutions at more attractive price points, for a diverse range of applications.

Multifield imaging is a new imaging technology that enables capturing multiple images simultaneously at various lighting conditions e.g. brightfield, darkfield, and backlight in a single scan.

Consider OLED display inspection, for example. Traditionally an automated inspection system would have required multiple passes, one each with backlight, darkfield, and brightfield lighting conditions. With a multifield solution, all three image types may be acquired in a single pass, greatly improving throughput and productivity.

Flat panel glass is inspected at every stage of manufacturing

So how is multifield imaging achieved? In this blog we’re more focused on applications. For those new to Time Delay and Integration (TDI), it is the  concept of accumulating multiple exposures of the same (moving) object, effectively increasing the integration time available to collect incident light. The key technology for a multifield linescan camera is the sensor uses advanced wafer-level coated dichroic filters with minimum spectral crosstalk to spectrally isolate three images captured by separate TDI arrays, i.e. wavelength division multifield imaging.

Multifield images on one sensor using filters to isolate wavelengths

This new technology significantly boosts system throughput as it eliminates the need of multiple scans. It also improves detectability as multiple images at different lighting conditions are captured simultaneously with minimum impact from mechanical vibration.

1stVision is pleased to offer our customers a multifield linescan camera from Teledyne Dalsa, the HL-HF-16K13T: https://www.1stvision.com/cameras/models/Teledyne-DALSA/HL-HF-16K13T

Contact 1stVision for support and / or pricing.

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

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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Computar ViSWIR Visible + SWIR lenses

1stVision is pleased to make available two new lens series from Computar: both the ViSWIR HYPER / APO Lens Series, and the VISWIR Lite Series. Traditionally, applications landed in either the visible or the SWIR range, so components tended to be optimized for one or the other. The new lens series are designed to perform well with for both visible and SWIR, enabling cost-effective and performant imaging systems for a range of applications.

ViSWIR Hyper / Multi-Spectral Lens Series were created for the latest Vis-SWIR imaging sensors, the IMX990/IMX991 SenSWIR, currently found in the new Allied Vision Goldeye G-130. The series was recognized as a Gold Honoree by Vision Systems Design in 2021:

With fully corrected focus shift in visible and SWIR range (400nm-1,700nm), spectral imaging is achievable with a single sensor camera by simply syncing the lighting. Per Sony, “the IMX990/IMX991 top indium-phosphorus (InP*2) layer inevitably absorbs some visible light, but applying Sony SWIR sensor technology makes this layer thinner, so that more light reaches the underlying InGaAs layer. The sensors have high quantum efficiency even in visible wavelengths. This enables broad imaging of wavelengths from 0.4 μm to 1.7 μm. A single camera equipped with the sensor can now cover both visible light and the SWIR spectrum, which previously required separate cameras. This results in lower system costs. Image processing is also less intensive, which accelerates inspection.”

With ViSWIR HYPER-APO, it is unnecessary to adjust focus for different wavelengths or to keep the high resolution from short to long working distances. The focus shift is reduced at any wavelength and any working distance, making the series ideal for multiple applications, including machine vision, UAV, and remote sensing.

Computar ViSWIR HYPER-APO lens series

Since diverse substances respond to differing wavelengths, one can use such characteristics as the basis for machine vision applications for materials identification, sorting, packing, quality control, etc. To understand the value of these lenses, see below for an example of conventional lenses that cannot retain focus across different wavelengths:

Conventional lenses only focus in specific wavelengths

Now see images across a wide range of wavelengths, with the award winning Computar lens, that retain focus:

Diverse materials under diverse lighting – in focus at each wavelength.
The same lens may be used effectively in diverse applications.

Also new from Computar is the VisSWIR Lite series, providing:

— High transmission from Visible to SWIR (400-1700nm) range
— Reasonable cost performance for narrow band imaging
— Compact design
Key features of Computar VisSWIR Lite seriesComputer

Computer ViSWIR Lite lens series

Which to select? APO or Lite series?

Contact 1stVision for support and / or pricing.

Contact us to talk to an expert!Give us some brief idea of your application and we will contact you to discuss.

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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Allied Vision G-130 TEC1 SWIR Camera

1stVision is pleased to announce that we can obtain Allied Vision’s new G-130 TEC1 SWIR camera for our customers. Utilizing Sony’s innovative IMX990 sensor, based on their SenSWIR technology, the camera is responsive in both the visible as well as the short-wave infrared range, spanning from 400 – 1700nm.

AVT G-130 TEC1 SWIR camera

While there are a number of cameras that cover short-wave infrared (SWIR) alone, from 900 – 1700nm, this sensor’s responsivity down to 400nm in the visible range opens up applications possibilities not previously possible with a single sensor camera.

Besides the wide spectral range, the sensor uses small 5µm pixels, with high quantum efficiency, offering precise detection of details.

The Goldeye 130 with IMX990 1.3MP SXGA sensor can deliver 110fps with Camera Link interface, or 94fps with GigEVision interface. The camera is fan-less, using thermoelectric sensor cooling (TEC1), yielding a robust and compact design.

Contact 1stVision for support and / or pricing.

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

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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Allied Vision Alvium with Sony Pregius Gen 4 Sensors

Allied Vision Alvium camera image

1st Vision is pleased to relay that Allied Vision has introduced new Alvium machine vision camera models featuring 4th gen IMX Sony Pregius S global shutter sensors. The sensors feature an improved back side illuminated pixel architecture that can capture light more effectively. This leads to improved quantum efficiency (QE) compared to 2nd and 3rd generation IMX sensors. Because of the decreased pixel size of 2.74µm, higher pixel densities and resolutions for the same optical format are possible.

Allied Vision Alvium

The IMX542 sensor in the 1800 U-1620 models has a 16:9 wide screen format similar to the IMX265 (2nd gen.). It is practically the same size but has almost twice the resolution. So, the FOV is nearly the same but at a much higher resolution. This sensor is especially suited for ITS applications.

The IMX540 sensor in the 1800 C/U-2460 models has an almost square format. Even though it is not much wider than the IMX304 (2nd gen.), it is considerably higher. It is a solid, lower priced alternative to the OnSemi Python 25k sensor, which has a similar resolution and aspect ratio, but is much larger.

The IMX541 sensor in the 1800 U-2040 models has a square format which was only available in the larger IMX367, but is now available as a C-mount camera in a sugar cube housing. This makes it especially suited for microscopy applications.

A summary of the new Alvium USB3 camera is as follows:

CameraSensorResolutionFormatFrames / Sec
1800 U-1620Sony IMX54216.2 MP5328×304022
1800 U-2040Sony IMX54120.4 MP4512×451217
1800 U-2460Sony INX54024.6 MP5328×460814
New Alvium cameras with Sony 4th Gen Pregius sensors

Contact 1stVision for support and / or pricing.

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

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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Opto Imaging Modules Provide a Turn-Key Solution

Demanding imaging applications require particular combinations of image sensor, lens, and lighting in order to achieve an optimal image.  It can be challenging to choose the right components and configure them in a compact space. An attractive solution for many is to use “Imaging Modules” which contain an integrated camera sensor, lens and lighting in an “all in one” housing.  A range of imaging modules are available, each configured to optimize component alignment and operations. The end-user may quickly deploy a new system, benefiting from the standardized systems, economies of scale, and expertise of the module builder.

Simplified example of imaging module key components

Opto Imaging GmbH offers imaging modules based on their more than 40 years experience in imaging.  Early leaders in imaging software, they also led with products and systems for stereo microscopy imaging, fluorescence imaging, metrology, surface imaging, and bioimaging.  They now offer Opto Imaging Modules, a collection of “plug-n-play” imaging systems for rapid deployment in diverse situations.

Here are 5 key benefits derived from using Opto Imaging Modules :

One unitCompact integrated sensor, lens, and lighting, optimally calibrated and tested
One wireUSB-C provides power, control signals, and images, and image data on a single cable
Plug and playRapid turn-key deployment into your environment, with minimal configuration, and confidence to achieve reliable results, thanks to pre-configuration by the manufacturer
Free viewer https://www.opto.de/en/software/opto-viewer/
SDK includedOr use any standard SDK you may prefer
Five key benefits of Opto Imaging Modules

Application areas include but are not limited to:

Machine vision microscopy: Hardness testing, bond inspection, scratch analysis, automated measurements and documentation, metrology, and more.

Industry 4.0 production micro imaging: With a measurement resolution of 1.8 micrometers per pixel, it enables the analysis of the smallest details.

Surface inspection: For example, of highly-reflective metal surfaces: https://www.opto.de/media/solino-slider.gif

Macro imaging: Traditional machine vision of scenes or objects larger than 20mmx20mm. Options include megapixel sensors and/or telecentric optics.

Watch this short video captured with an Opto Imaging module, capturing blood cells in a biomedical application: https://www.youtube.com/watch?v=E4Uy00rzejI 

Demonstrations are available: virtual demos are available by appointment, and demo loaners are available to try in your own environment.

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Give us some brief idea of your application and we will contact you to discuss camera options.
Opto Imaging Modules offer varied sub-components pre-configured and calibrated to work together

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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Teledyne DALSA launch “Linea Lite” line scan cameras

Linea Lite and Linea sizes compared

The “Linea Lite” 2k and 4k line scan cameras provide industry-leading performance in a compact package. Built for a wide-range of machine vision applications, the new Linea Lite cameras feature a 45% smaller footprint than the original Linea and are based on a brand new, proprietary CMOS image sensor designed by Teledyne Imaging. This expands on the success of the Linea series of low cost, high value line scan cameras.

Designed to suit many applications, the Linea Lite offers customers a choice between high full well mode or high responsivity mode, via easy to configure gain settings.

Linea Lite (left) vs. original Linea (right – with lens) (Note: original Linea series also available)
Linea Lite 4k – Linea 4k

The cameras are available in 2k and 4k resolutions, in monochrome and bilinear color. Linea Lite has all the essential line scan features, including multiple regions of interest, programmable coefficient sets, precision time protocol (PTP), and TurboDrive™. With GigE interface and power over Ethernet (PoE), Linea Lite is an excellent fit for applications such as secondary battery inspection, optical sorting, printed materials inspection, packaging inspection, and many more.

Linea Lite Specifications

Download full specifications here.

KeyFeatures:

– 7µm or 14µm pixels

– 2k and 4k resolutions

– Configurable full well

– Precision time protocol

– Selectable 8 or 12-bit output

Contact us for a quote

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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Types of 3D imaging systems – and benefits of Time of Flight (ToF)

Time Of Flight Gets Precise: Whitepaper

2D imaging is long-proven for diverse applications from bar code reading to surface inspection, presence-absence detection, etc.  If you can solve your application goal in 2D, congratulations!

But some imaging applications are only well-solved in three dimensions.  Examples include robotic pick and place, palletization, drones, security applications, and patient monitoring, to name a few.

For such applications, one must select or construct a system that creates a 3D model of the object(s).  Time of Flight (ToF) cameras from Lucid Vision Labs is one way to achieve cost-effective 3D imaging for many situations.

ToF systems setup
ToF systems have a light source and a sensor.

ToF is not about objects flying around in space! It’s about using the time of flight of light, to ascertain differences in object depth based upon measurable variances from light projected onto an object and the light reflected back to a sensor from that object.  With sufficiently precise orientation to object features, a 3D “point cloud” of x,y,z coordinates can be generated, a digital representation of real-world objects.  The point cloud is the essential data set enabling automated image processing, decisions, and actions.

In this latest whitepaper we go into depth to learn:
1. Types of 3D imaging systems
2. Passive stereo systems
3. Structured light systems
4. Time of Flight systems
Whitepaper table of contents
Download

Let’s briefly put ToF in context with other 3D imaging approaches:

Passive Stereo: Systems with cameras at a fixed distance apart, can triangulate, by matching features in both images, calculating the disparity from the midpoint.  Or a robot-mounted single camera can take multiple images, as long as positional accuracy is sufficient to calibrate effectively.

Challenges limiting passive stereo approaches include:

Occlusion: when part of the object(s) cannot be seen by one of the cameras, features cannot be matched and depth cannot be calculated.

ToF diagram
Occlusion occurs when a part of an object cannot be imaged by one of the cameras.

Few/faint features: If an object has few identifiable features, no matching correspondence pairs may be generated, also limiting essential depth calculations.

Structured Light: A clever response to the few/faint features challenge can be to project structured light patterns onto the surface.  There are both active stereo systems and calibrated projector systems.

Active stereo systems are like two-camera passive stereo systems, enhanced by the (active) projection of optical patterns, such as laser speckles or grids, onto the otherwise feature-poor surfaces.

ToF diagram
Active stereo example using laser speckle pattern to create texture on object.

Calibrated projector systems use a single camera, together with calibrated projection patterns, to triangulate from the vertex at the projector lens.  A laser line scanner is an example of such a system.

Besides custom systems, there are also pre-calibrated structured light systems available, which can provide low cost, highly accurate solutions.

Time of Flight (ToF): While structured light can provide surface height resolutions better than 10μm, they are limited to short working distances. ToF can be ideal for or applications such as people monitoring, obstacle avoidance, and materials handling, operating at working distances of 0.5m – 5m and beyond, with depth resolution requirements to 1 – 5mm.

ToF systems measure the time it takes for light emitted from the device to reflect off objects in the scene and return to the sensor for each point of the image.  Some ToF systems use pulse-modulation (Direct ToF).  Others use continuous wave (CW) modulation, exploiting phase shift between emitted and reflected light waves to calculate distance.

The new Helios ToF 3D camera from LUCID Vision Labs, uses Sony Semiconductor’s DepthSense 3D technology. Download the whitepaper to learn of 4 key benefits of this camera, example applications, as well as its operating range and accuracy,

Download whitepaper
Download whitepaper
Time Of Flight Gets Precise: Whitepaper
Download Time of Flight Whitepaper

Have questions? Tell us more about your application and our sales engineer will contact you.

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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Keys to Choosing the Best Image Sensor

Keys to Choosing the Best Image Sensor

Image sensors are the key component of any camera and vision system.  This blog summarizes the key concepts of a tech brief addressing concepts essential to sensor performance relative to imaging applications. For a comprehensive analysis of the parameters, you may read the full tech brief.

Download Tech Brief - Choosing the Best Image Sensor

While there are many aspects to consider, here we outline 6 key parameters:

  1. Physical parameters


    Resolution: The amount of information per frame (image) is the product of horizontal pixel count x by vertical pixel count y.  While consumer cameras boast of resolution like car manufacturers tout horsepower, in machine vision one just needs enough resolution to solve the problem – but not more.  Too much resolution leads to more sensor than you need, more bandwidth than you need, and more cost than you need.  Takeaway: Match sensor resolution to optical resolution relative to the object(s) you must image.

    Aspect ratio: Whether 1:1, 3:2, or some other ratio, the optimal arrangement should correspond to the layout of your target’s field of view, so as not to buy more resolution than is needed for your application.



    Frame rate: If your target is moving quickly, you’ll need enough images per second to “freeze” the motion and to keep up with the physical space you are imaging.  But as with resolution, one needs just enough speed to solve the problem, and no more, or you would over specify for a faster computer, cabling, etc.

    Optical format: One could write a thesis on this topic, but the key takeaway is to match the lens’ projection of focused light onto the sensor’s array of pixels, to cover the sensor (and make use of its resolution).  Sensor sizes and lens sizes often have legacy names left over from TV standards now decades old, so we’ll skip the details in this blog but invite the reader to read the linked tech brief or speak with a sales engineer, to insure the best fit.

  2. Quantum Efficiency and Dynamic Range:


    Quantum Efficiency (QE): Sensors vary in their efficiency at converting photons to electrons, by sensor quality and at varying wavelengths of light, so some sensors are better for certain applications than others.

    Typical QE response curve

    Dynamic Range (DR): Factors such as Full Well Capacity and Read Noise determine DR, which is the ratio of maximum signal to the minimum.  The greater the DR, the better the sensor can capture the range of bright to dark gradations from the application scene.

  3. Optical parameters

    While some seemingly-color applications can in fact be solved more easily and cost-effectively with monochrome, in either case each silicon-based pixel converts light (photons) into charge (electrons).  Each pixel well has a maximum volume of charge it can handle before saturating.  After each exposure, the degree of charge in a given pixel correlates to the amount of light that impinged on that pixel.

  4. Rolling vs. Global shutter

    Most current sensors support global shutter, where all pixel rows are exposed at once, eliminating motion-induced blur.  But the on-sensor electronics to achieve global shutter have certain costs associated, so for some applications it can still make sense to use rolling shutter sensors.

  5. Pixel Size

    Just as a wide-mouth bucket will catch more raindrops than a coffee cup, a larger physical pixel will admit more photons than a small one.  Generally speaking, large pixels are preferred.  But that requires the expense of more silicon to support the resolution for a desired x by y array.  Sensor manufacturers work to optimize this tradeoff with each new generation of sensors.

  6. Output modes

    While each sensor typically has a “standard” intended output, at full resolution, many sensors offer additional switchable outputs modes like Region of Interest (ROI), binning, or decimation.  Such modes typically read out a defined subset of the pixels, at a higher frame rate, which can allow the same sensor and camera to serve two or more purposes.  Example of binning would be a microscopy application whereby a binned image at high speed would be used to locate a target blob in a large field, then switch to full-resolution for a high-quality detail image.

For a more in depth review of these concepts, including helpful images and diagrams, please download the tech brief.

Download tech brief - Choosing the Best Image Sensor

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.

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1stVision Announces New Logo, Refreshed Website, and Continued Investment in Customer Support

1stVision

We are excited to be shining the spotlight on ourselves today as we introduce for the first time our new logo and website user interface (UI) design . Our new logo signifies our continuous high-level commitment to all your machine vision needs and captures the new foundation laid by a capital investment by and strategic partner relationship with Next Imaging.

On February 7, 2020, we announced that 1st Vision had been acquired by Next Imaging but would continue doing business as 1st Vision, Inc. We are keeping our well-known identity and presence in the North American Market and looking to excel even further at becoming your 1st choice for all your imaging requirements.

Check out our new website!

1st Vision’s sales engineers have an average of 20 years experience to assist in your camera selection.  Representing the largest portfolio of industry leading brands in imaging components, we can help you design the optimal vision solution for your application.