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How to select the best industrial camera, Step 2 Preliminary Camera Selection

Posted by Gretchen Alper on Tue, Jan 24, 2012

Choosing the correct industrial camera for your machine vision system from the beginning can eliminate costly redesigns or upgrades in the future.  The question is, how do you determine the best camera? Best is always subject to your needs.  For Step 1, click here.

Create a list of possible cameras with the desired functionality

In our previous blog we talked about the first steps to identify the most important camera parameters for your system and start your research of available products. Suppose you have determined you need a lot of contrast in your image which means you need a high dynamic range, and your other system conditions have led you to conclude you need 4 Megapixels with a frame rate of at least 150 frames per second.  The system is already based on the Camera Link Adimec quartz checklistinterface and because several images are used for one measurement, you want global shutter technology to minimize the image-to-image effects.  This can help you narrow down your search to cameras based on a specific sensor, in this case say the CMOSIS CMV4000.  As you begin your search, you may find it difficult to compare camera specifications as each supplier may have determine the values in a different way or under different conditions even though they all use the same image sensor.  Another thing that is confusing is that cameras utilizing the same sensor can show different values for several parameters, such as dynamic range.

Detailed comparison of cameras by using datasheets and product specification documents (PSDs)

For example, the Point Grey Gazelle GZL-CL-41C6, the Adimec QUARTZ Q-4A180, and the Vieworks VC-4MC-M160 all utilize the CMOSIS CMV4000 image sensor.  From readily available and downloadable documentation from the manufacturers, you can find the following:

Point Grey Gazelle GZL-CL-41C6

SNR 58 dB

Adimec QUARTZ Q-4A180m/CL

Dynamic Range 60 dB

Vieworks VC-4MC-M160

Dynamic Range 56 dB

These values can depend on the way in which the measurements were made, also Point Grey presents the information as signal to noise ratio (SNR) rather than dynamic range.  The EMVA 1288 was developed to allow a consistent way of quantifying and comparing camera parameters.  Some camera manufacturers have had this analysis done by a third party or have done it themselves and share the data.  The cost for the analysis or equipment analysis is somewhat high so some have developed their own methods.  Even with comparable data, you still need to know which exact value is required by your system (see next blog).

Consult experts and references to narrow down to 3 to 5 suppliers

Also, you may still have a relatively long list of potential options at this point.  Perhaps this list can be further narrowed down by asking either colleagues or industry professionals to share their experiences (LinkedIn groups are a great resource).  As the cameras are going to be used in your systems, you may seek references and do some research on the stability and consistency of the manufacturer in addition to individual camera performance.

Before camera evaluation starts . . .

Before you start ordering evaluation cameras and talking to camera vendors try creating a checklist of items that are not camera properties but will affect the long-term buyer-supplier relationship you will have. These include items such as support level, quality of service, long-term supplier, markets served, etc.

Once you have done this, you will likely have a shorter list of 3 -5 possibilities and now you are ready to start evaluations…Click here for the last steps and to download all 3 steps in 1 document.

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Topics: Vision System Optimization

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