Why shouldn’t I buy a $69 webcam for my machine vision application?

This is a question we get asked frequently: “Why should we pay $200 plus for your board level machine vision camera when we can just get a webcam for $69?”

A great question and maybe you can, but what ARE the differences?

Basically, there are just a few questions you need to answer to see if you should use a webcam for you machine vision application which are as follows:

Do you need to program to integrate the video into an application with processing or control?
Do you need consistent image quality?
Are you doing computer vision (the computer is making decisions based on the images) or are you just viewing the images visually?
Do you care if the camera specifications change over your product’s life cycle?
Is the object under inspection moving?
Do you need to control when you take the picture or interface to a trigger or strobe?
Do you need to be able to choose what lens you will need?

If the answer to any of the above are YES, then a webcam will NOT work well or at all for your application. If the answers are NO, then by all means, you might be able to save money and just use a low-cost webcam. (You can stop reading here if you want, or continue for more details below).

Machine Vision Camera Software

Webcams do NOT come with a SDK as they are made to show video only. They normally provide a universal video driver, and also an application for viewing video.

Industrial machine cameras come with a SDK programmable in C/C++/C#/etc. It allows you to programmatically control the camera for both data acquisition and control of the camera’s parameters. (Example HERE to show extensive support of various operating systems and download)

Moving objects

Webcams have rolling shutter sensors which mean they cannot acquire images of moving objects without ‘smearing’ them. Industrial machine vision cameras use sensors with global shutters providing the ability to freeze the image to produce non smeared images of moving objects.

Example: Without adequate shutter speed with a global shutter, image will be blurry with motion

Trigger and Strobe Control

Webcams only have an interface to the USB data, whereas industrial machine vision cameras have hardware and software inputs and outputs. These allow for exact timing for a trigger to take a picture and a strobe to illuminate the object.

Example: External trigger control is tightly timed with IO including light flash. Courtesy of IDS Imaging

Camera Specs Changing over time

Webcams just need to show you video! In turn the manufacturers are not concerned if the sensors inside the camera change every six months. Whether the sensitivity changes by 10% makes no difference when you are just video conferencing with Grandma.

Industrial machine vision cameras are made with image sensors that don’t go obsolete every 6 months, but rather companies hope for 10 year life spans. It makes a huge difference if you are doing a computer vision algorithm that you have 5 man years of software development and the sensor’s sensitivity changes by even 1%.

Furthermore, the form factor of webcams change frequently as well. This doesn’t make a difference when it is just on your desk. It makes a huge difference when your camera and lens is fixtured in a machine that has 500 hours of CAD work to design, much less build. Moving the camera and lens 10cm might not be possible!

Do you need to choose your lens?

Webcams come with an integrated lens that is suitable for general viewing, and this lens is integrated with the camera and not changeable. Industrial machine vision cameras come with no lenses as not only do lenses come in a variety of focal lengths for different magnification, but also lenses coming in a variety of resolutions. Choosing a lens requires you to know the size of the sensor, your working distance, your field of view, and the pixel size. (See related educational blogs on lenses at end of this post)

What are your options for a low cost camera solution?

If you need industrial machine vision camera solutions with a solid SDK, long life cycles, at a low price, there several solutions to consider. Rolling shutter imagers are always lower price which are always a place to start along with USB2 interfaces. Read our previous blog HERE which outlines some specific models which are low cost. There is also a great new platform coming providing 5 Megapixel resolution with a rolling shutter imager, but with great performance for $280! Contact us for more details.

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

Imaging Basics – Calculating Lens Focal length

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Not All Lenses are Created Equal! Lens MTF Comparisons

December 10, 2018December 17, 2018

Learn about the new 5GigE camera interface

Machine vision interfaces have continued to evolve over the years increasing data throughput and cable lengths. Commonly used interfaces are GigE and USB3. However, 5GigE is an interface now gaining attention in the industrial imaging / machine vision market with some nice advantages.

We will outline the benefits of 5GigE, but first, lets give a brief overview of the commonly used camera interfaces, with their pluses and minuses:

GigE / GigE Vision

110 MB/s of sustainable throughput. In real world terms, a HD, 2MP camera can get 50-55 fps in 8 bit mono or 8 bit color mode. Note, this isn’t real HD, since you need 60 FPS.
Data cable lengths up to 100m using regular CAT 5e/6 cable.
Easy to put multiple cameras on a system.

USB 3 / USB3 Vision

420 MB/s of data throughput. A HD 2MP camera can run 60 fps in 8 bit mono or color and can also run RGB at 60 FPS no problem. With the higher throughput, a 5MP camera can achieve 85 fps in 8 bit mode.
Data cables up to 5 meters and up to 20 meters with active cables. However, active cables can be quite costly, adding up to $200 in cost.
Not as easy as GigE to put multiple cameras on a system, and gets harder with each additional camera, especially if you have limited USB3 controllers.

As a note, there is no cost difference when using cameras with the same sensor from the same manufacturer with USB or GigE! They will cost about the same with no premium for one interface over the other.

What are the limitations of GigE and USB3 now solved by 5GigE?

USB3 is limited in cable length, so going faster than GigE is great, but you can not have long cable lengths.
GigE has cable lengths up to 100 meters, but is limited to ~ 110MB/s of data, so you do not have the high frame rates as in a USB3 camera.
USB3 in 4+ camera systems is not as stable as GigE AND you’re still limited on cable lengths.

Wait! – What about 10GigE?

Up until now, 10G was the next interface. However, the jump to 10G has quite a few limitations as outlined below.

Heat generation is significant, so cameras are large and not in the smaller 29 x 29mm cube form factor.
Not a lot of demand for very high speed 10G, so not a lot of sensors being offered
Minimal number of manufacturers for 10G, higher cost.
Special cabling, either optical or high quality cat 7.

What we have found is that there are several types of applications for 10G cameras and are as follows

Applications where you need 10G of speed of course (high resolution + fast frame rates)
Require greater than 110MB/s of data and need long cable lengths.
Where there is the required combination of 110MB/s for high frame rates, multiple cameras and long cable lengths, 10G is a perfect solution.

We have seen that the need for higher bandwidth + long cable lengths is more prominent vs. the real need for 10GigE!

Introducing 5GigE that provides increased bandwidth, long cable lengths at reasonable prices! or N Base T.

5GigE (also known as N Base T) has become a new standard for industrial, machine vision cameras.

In the general compute world, a much much larger market than vision, there has also been a need to go faster than GigE. However, the issue of replacing the existing cabling is the major issue preventing this. If you think of a big box store, say a Home Depot for instance, the amount of cabling is huge. Ripping that out and rewiring far exceeds the cost of the equipment to use it!

5G was made to go faster, but use existing cabling. Regular cat6e cable can be used, and 5G is a subset of 10G, so all switches etc. can be kept in service.

5G gives users in the vision market USB3 speeds, but with ALL of the regular GigE features, at a very small premium!

October 15, 2018December 17, 2018

Learn about CoaXpress and frame rates achievable with Allied Vision’s “Bonito Pro” cameras with CXP-6

What is CoaXPress, especially with “CXP-6” capability?

CoaXPress is an established industry standard allowing high speed communications over coaxial cable. The current version supports bit rates up to 6.25 Gbits/sec over a single coaxial cable. When used in parallel, two or more coaxial cables can provide incremental speed gains. The naming convention associated with CoaXPress signify the bit rate as seen in the chart below. In cases that you see CXP-6 has a bit rate of 6.25 Gb/s. The 4 x means the number of lanes. Multiply the 2 and you get your total bit rate.

The new Allied Vision Bonito Pro cameras utilize 4 DIN 1.0/2.3 connectors on a CXP-6 interface (4 lanes) x 6.25Gbits/Sec. This allows for resolutions of up to 26 megapixels to reach 70 frames per second (fps). The first two Bonito PRO models (Bonito PRO X-2620 and X-1250) support high resolution with 26.6MP and 12.5MP at 80 and 142 fps respectively.

The Bonito PRO cameras are ideal for a wide range of applications including, 2D/ 3D surface inspection, high speed printing, PCB & Electronics inspection.

Even faster frame rates can be achieved using the Bonito Pro X1250 (12.5MP) in partial scan mode. Set to a 768 line height, a rate of 503 fps can be achieved!

The following video’s are good representations of what this relates to in real applications which you can appreciate.

Full specifications for the Allied Vision Bonito Pro cameras can be found HERE, but main features and benefits include:

Sensors available in Monochrome (X-1250B) and Color (X-1250C) and extended near-infrared (X1250B NIR ) models
On board defect pixel and 2D fixed pattern noise correction for improved image quality
Fan-less design for industrial imaging applications.
DIN 1.0 / 2.3 CoaXPress connections for secure operation in industrial environments.
Single cable solutions using trigger and power over CoaXPress (PoCXP)

UPDATE: New video of the Bonito Pro detailing the multi-ROI function

July 18, 2018September 5, 2018

Dalsa Nano M2450 polarized camera: Resolving defects that are undetectable with traditional imaging!

The first Genie Nano camera model with a quad-polarizer filter using the Sony Pregius IMX250-MZR 5.1MP monochrome image sensor is now available. The Teledyne Dalsa Nano M2450 camera incorporates the nanowire polarizer filter allowing detection of both the angle and amount of polarized light.

What problems can the Nano M2450 polarized camera solve?

Polarized filtering can reduce the effects of reflections and glare from multiple directions and reveal otherwise undetectable features in the target scene. Polarization enables detection of stress, birefringence, through-reflection and glare from surfaces like glass, plastic, and metal. Sony’s newest image sensor, with its pixel-level polarizer structure, enables the detection of both the amount and angle of polarized light across a scene.

Four different angled polarizers (90°, 45°, 135° and 0°) are positioned on each pixel, and every block of four pixels comprises a calculation unit.

How does polarization work? Theory of operation

Polarization direction is defined as the electrical direction. Light, with its electrical field oscillating perpendicular to the nano wire grid, passes through the filter while that in the parallel direction is rejected.

For Polarized light, only the portion of the light vector perpendicular to the angle of the nanowire filter grid passes.

For example, with a wire-grid polarizer filter at 90 deg. to the maximum transmission is for polarized light at an angle of 0 deg.

The polarizer filter is placed directly on the sensor’s pixel array, beneath the micro-lens array. This design, compared to polarize filters on top of the micro lens array reduced the possibility of light at a polarized angle being misdirected into adjacent pixels (cross talk) and incorrectly detected at the wrong angle.

The Genie Nano’s polarizer filter on the camera sensor is a 2 x 2 pattern, with each pixel having a nanowire polarizer filter with different angles (90, 45, 135 and 0 degree’s)

The image output pattern of the monochrome camera is arranged in 2 x 2 pixel block as follows:

That is, the first line output is an alternating sequence of pixels 0 & 35 degrees, with the following line of 45 and 90 degrees.

Given the proportion of light available through these four filters, any angle of polarized light can be calculated. Any given state of polarization can be composed by two linearly polarized waves in perpendicular directions. The state of polarization is determined by the relative amplitude and difference in phase between the two component waves.

Calculations on the 2×2 filter blocks result in a single pixel for each polarizer filter angle, therefore the resulting image is one fourth the original image resolution. For example, with an original image of 2464×2056, the resulting image is 1232×1028 (original buffer width/2 and original buffer height/2) for a single polarizing angle.

Teledyne Dalsa offers a Polarization demo user interface making it easy to test the polarization techniques for various applications. This includes the ability to see the results of various processing algorithms with the summed images.

Dalsa Polarization demo — As part of the demo program, images can be displayed with pseudo-color mapping

In summary, the new Dalsa Nano M2450 polarized camera can help resolve defects not detected by traditional imaging! Contact 1st Vision to arrange a camera demo in which we will provide the demo polarization software as well or discuss your application. Or click HERE to request a quote

Need line scan? – With the addition of the Genie Nano polarized model, Teledyne DALSA is the first company to offer polarization for both area and line scan (Piranha™4 polarization) cameras

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