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.

Considerations for Color machine vision cameras using a Bayer filter – White paper

Bayer image
Dalsa Falcon camera

Users of single chip color machine vision cameras have lots of choices in camera features. The following are a few issues relating to these types of cameras that users need to be aware of when they are choosing their camera type.

First, its important to understand how a “single chip” machine vision color camera creates a color image. Thanks to Bryce Bayer of Eastman Kodak, we have the “Bayer” filter mosaic filter pattern that generates a color image through interpolation which is the technique used in most machine vision cameras today.

Bayer filter
Bayer Filter

From a macro view, using the Bayer filter, we collect light onto individual pixels through each of the red, green and blue filters which assigns intensity values. Using various interpolation methods, each pixel uses data from adjacent pixels to determine its color to generate a nice color image.

There are several considerations in color imaging during this process such as:
1 – Bayer conversion – Understanding this is important as it may effect the computer CPU load and image fidelity.
2 – Frame rates – Depending on the color format (ie. RGB vs Raw), you will need to understand how this effects the camera frame rate requirements and camera interfaces.
3 – Color formats – Depending if the application simply wants to identify a blue vs red part vs doing a more in depth color analysis will determine which color format is utilized.

1stVision has published a white paper addressing these considerations in the link below.

Download this comprehensive white paper – “Considerations for Color machine vision cameras using a Bayer filter. Click HERE.

For any color application, there is various color camera technology that needs to be considered first. 3-Chip Color machine vision cameras have advantages over Bayer color cameras in which color fidelity and resolution are superior. Additional resources on each aspect is below:

3 chip color camera block diagram
Block Diagram of 3 chip color camera – Courtesy of JAI

Color Fidelity – If your application requires high color fidelity and trying to detect small differences in color, 3 chip color cameras should be also considered. Learn more in this related blog HERE.

Resolution – Due to the interpolation in Bayer color cameras, the overall resolution is reduced significantly. In applications where resolution AND color are important, 3 chip color cameras provide these advantages. Comparison images and further explanation can be found in this blog HERE.

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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

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IDS uEye cameras now focus automatically! Learn how to optimize your application

IDS camera

IDS Imaging has released its new contrast-based autofocus features in the popular LE board level cameras. These additions take advantage of standard liquid lenses from Varioptic with resolutions up to 18 megapixels. The uEye software now comes with an intuitive GUI with adjustable regions of interest and various image sharpness measurement algorithms.

As much as “Auto focus” seems like it would be the flip of a switch, its important to understand the various methods used in the image analysis. In order to focus an image, algorithms are needed to measure image sharpness which is relayed to the liquid lens to make adjustments. These methods as based on principles in measuring edge sharpness to analyzing histogram values of the pixel grey scales.

Measuring image sharpness additionally has various algorithms which which can be run providing more exact methods versus basic analysis. It is important to understand these methods as additional processing power is required, effecting the overall camera frame rate.

IDS Imaging has a “Tech Tip” which covers various auto focus methods, defines the characteristics of search algorithms and how they effect speed and provides application examples. Click the icon below to download.

Click to download tech tip

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

Related Blogs & Products
IDS UI-1007XS – AutoFocus, 5MP camera for < $300 Click HERE for details

Everything you need to know about 10GigE Vision cameras! – White Paper

10 GigE Vision compliant cameras are easy to integrate enabling more machine vision applications and image processing. Camera image sensors have continued to increase in resolution which requires higher bandwidth interfaces to achieve high frame rates. 10 GigE cameras are a great solution as implementation is less costly and complex versus camera link and CoaxPress.

Baumer has a comprehensive white paper outlining application benefits for 10GigE Vision and gives recommendations on system architecture – Downloaded HERE

Aside from the features of 10GiGE Vision, the Baumer VLXT series cameras are extremely feature rich and cost competitive making them an excellent choice for 10GigE Vision cameras.

11 Key Features are listed below with many being unique, solving more vision applications in 10 GigE Vision cameras


1 – True 10GigE bandwidth! –
2 – Liquid lens & Canon EF mount control
3 – Exposure times down to 1uS with Sony Sensors
4 – Power outputs (4x) for direct driving LED lights eliminating a lighting controller.
5 – IP67 Ratings and extended temperatures for harsh environments
6 – IEEE 1588 Precision Timing protocols for synchronized timing with multiple devices.
7 – Long cable lengths up to 55 meters (Cat 6) and 70+ meters with Cat 6a / 7 and longer with optional fiber optic interface.
8 – Standard low cost 10GigE NIC’s can be used opposed to some manufacturers requiring special NICs
9 – Fully GigE Vision compliant for easy implementation with the benefits of high bandwidths. Allows support of third party software libraries.
10 – RS232 support
11 – On board JPEG compression available

Full specifications on the Baumer VLXT cameras which range from 3 megapixels to 12 megepixels can be found HERE

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