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%.

In fields such as computer vision that require image processing, telecentric lenses are widely used because of their high-precision imaging effects, which make image processing more precise.

Thorlabstelecentric lens

In aircraft photography and telephoto photography, telecentric lenses can capture images with strong three-dimensionality and high precision, and are widely used.

Telecentric lens is a type of optical lens, also known as television lens, or a telephoto lens. Through special lens design, its focal length is relatively long, and the physical length of the lens is usually smaller than the focal length. The characteristic is that it can represent distant objects larger than their actual size, so it can capture distant scenery or objects more clearly and in detail.

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:

Telecentric Lensbuy

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)

The working principle of a telecentric lens is to use its special structure to disperse light evenly and project the image onto a sensor or film. This feature allows it to achieve better imaging results when shooting scenes far away from the subject. So, what are the characteristics of telecentric lenses?

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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.

Telecentric lensworking distance

The edge imaging of the telecentric lens will not bend. Even at the edge of the lens, the lines still maintain the same intersection angle with the central axis of the lens, so high-precision images can be taken.

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.

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!

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).

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!

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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.

Telecentric lenses are widely used in scenes such as sports events, wildlife and nature photography, and astronomical observations, because these scenes often require shooting or observing objects from a long distance. Telecentric lenses can bring distant objects “closer” while maintaining the clarity and detail of the picture.

Telecentric lens photographytutorial

Because of the orthogonal projection, the telecentric lens can maintain the proportional relationship of space, making the captured images have a strong three-dimensional sense.

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.

Bitelecentric lens

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Due to the special internal optical structure, the telecentric lens can keep the light entering the lens parallel at all positions, which means that the image lines captured by the lens will remain straight without bending or deformation.

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?”

In some professional photography, telecentric lenses are often used, such as architectural photography, product photography, etc.

In addition, due to the long focal length of telecentric lenses, they can achieve background blur and shallow depth of field, making the subject more prominent when shooting, so they are also widely used in portrait photography.

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.

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)