The Imaging Source blog

May marks the first anniversary of Nikon Metrology's designation of The Imaging Source as a key supplier within their Strategic Partnership program. Nikon Metrology provides precision instruments for optical inspection and visual and mechanical metrology solutions. In partnering with The Imaging Source, Nikon Metrology is able to offer their customers a wider pallet of imaging hardware for inspection needs - enabling greater product precision and flexibility.

The anniversary provides an opportunity to express our appreciation for being part of a program which supports Nikon's goal of offering the widest range of metrology and microscope-imaging solutions possible. The Imaging Source looks forward to contributing to the continuing success of Nikon Metrology's Strategic Partner Program.

The following interview with The Institute for Printing (iPrint) gives specific application information about the DMK 33GP031 mentioned in our May 1, 2017 blog post. If you would like more information about the Inkjet Training course, please visit iPrint.

You chose the camera model DMK 33GP031.
Why was this particular model right for your application?
The DMK 33GP031 fulfills all demands for available drivers (our inkjet analysis system works primarily with Matlab drivers), synchronization, resolution, color depth and frame rates necessary for the analysis of inkjet systems and this with, to our knowledge, an unbeatable price to performance ratio. For many inkjet analyses (especially volume measurement and measurements made using multiple independent color channels) multiple cameras are necessary. Thanks to the Gigabit Ethernet interface, we can equip all of our controllers with minimal effort.

What specifically were the cameras used for?
During the Inkjet Training course, we use the DMK 33GP031 for inkjet droplet analysis (dropwatching). The camera exposure, droplet generator and flash diode are synched together using a FPGA-based controller. Inkjet drops have a velocity of approximately 1-20 m/s. Very short flash durations are required in order to capture the smallest high-speed drops with minimal motion distortion. With a flash duration of only a microsecond and a droplet speed of 10 m/s the droplet image is stretched to 10 µm. By controlling the flash durations, several droplets can be stacked. By illuminating a droplet twice at different points during its flight, droplet speeds or flight angles can be determined independent of the background fluctuations influencing droplet velocity (jitter).

In order to capture and measure details of droplet formation, resolutions of approximately 1 - 2.5 µm /pixel are necessary. With pixels measuring 2.2 µm, the DMK 33GP031's pixels are already quite small. We were able to use an inexpensive standard lens with minimal enlargement in order to reach the resolution we needed. Additionally, color information is valuable for interpolating contours or in order to stack multiple measurements. With 12-bit color depth, the DMK 33GP031 offers adequate color information for most inkjet analyses. Thanks to the 5 MP resolution, we can maintain a large field of view even at high resolutions.

In comparison to the previous model, the DMK 33GP031 is also able to reach higher frame rates due to its 12-bit color depth; it supports controlled exposure times via the trigger which allowed for greatly simplified and efficient synchronization with our analysis system. A significant additional plus point for the camera is its high frame rate when using a reduced region of interest (ROI). At 2592 x 24 pixels, we reached frame rates of up to 500Hz; when used with two cameras and layered measuring techniques, we were able to verify the presence of all droplets with frequencies of over 10kHz.

How do the images/data you acquire from the cameras figure into your application (e.g. quality control etc.)?
The captured images enable us to make adjustments to the settings of the printing system or printer itself which means printing with higher quality and efficiency. Because each Piezo inkjet printhead requires a slightly different working voltage to produce the same droplet velocity, printhead manufacturers specify a nominal voltage with which a nominal droplet size and velocity can be achieved.

In order to reach the same results using ones own printing fluid/ink with the specified nominal voltage as those of the test ink, we use droplet analysis to test several nominal voltages until we reach settings that will give us the desired printing properties.

What software did you use in connection with the cameras?
We used Matlab, IC-Capture and IC-Measure (we also use the DMK 23GP031 on our microscopes).

How was your experience with the cameras and the software?
The performance of The Imaging Source cameras is very good. The high-performance driver package enables simple, efficient integration. Occasionally, the Matlab interface had some problems during longer live previews on lower-performace PCs. In such cases, we use IC Capture for the live preview before the measurements are made; in settings it's possible to change from Live-Preview to Matlab. IC Capture is also a helpful tool for the hassle-free recording of image sequences and with which to test camera settings and performance. We also use IC Measure in conjunction with our microscopes which with its variety of measurement capabilities and compatibility, we find it to be an excellent tool for microscopy.

The following is an overview of an inkjet technology workshop and their use of the DMK 33GP031. For more technical information about how the DMK 33GP031 was used in the iPrint workshop lab, please see the interview here.

Since the 1970s when inkjet printing first became commercially viable, the technology has commanded the continued interest of researchers. In short, it is a no-contact method for the digital delivery and positioning of extremely small volumes of material or fluid with precision and high frequency. Inasmuch, inkjet technology is fundamentally a form of additive manufacturing; currently used in printed electronics, direct printing, ceramics and textiles and even with experimental jetable fluids and substrates such as live-cell printing for biofabrication, organic semi-conductors and organic light-emitting diodes. The Institute for Printing (iPrint) at the College of Engineering and Architecture at the University of Applied Sciences of Western Switzerland began offering an inkjet training course in 2015 which multidisciplinary professionals a week of theoretical and practical training with the various components of inkjet systems.

During the course, participants learn a key aspect of the printing process is determining the print quality delivered by an inkjet print head. This monitoring process begins with the properties of the jetted drop: the drop velocity, jetting direction, presence of satellite drops and drop volume. These droplet properties must be tightly adjusted in order to achieve and maintain the precision required by the application at hand. Machine vision systems are used to image the droplets during printing which allows for the continuous measurement of droplet properties - a process known as dropwatching. There are many possible imaging configurations for dropwatching, each with its own advantages: nozzle plate analysis, multi-camera dropwatching, overlaid imaging, multi-wavelength dropwatching or dropwatching in the printing gap. For their course, iPrint selected The Imaging Source's DMK 33GP031 industrial monochrome cameras. Regardless of which method is preferred, dropwatching is critical for performance optimization, print system (or print head) analysis, reliability verification and monitoring of the printing process.

As iPrint notes on their website, [inkjet research is] "by its very nature, multidisciplinary as it requires cutting-edge skills from various domains, notably those of mechanical engineering, chemistry and nanotechnologies." Typical participants are highly-skilled engineers or chemists who are experts in one area of inkjet but who might have only a limited working knowledge of other aspects of the technology; these participants are looking to broaden their knowledge base and develop a cross-system awareness of the entire process.

From April 3-6, The Imaging Source welcomed visitors to its booth at Automate 2017. On display were the 42 MP autofocus camera, USB and GigE color and monochrome cameras featuring the latest Sony and On Semiconductor sensors as well as The Imaging Source's new stereo 3D-vision system.

As North America's premier automation trade show, Automate 2017 hosted industry leaders in robotics, machine vision, metrology as well as other automation sectors. The biennial show, which took place in Chicago, experienced a nearly 25% increase in exhibitors over 2015. Robotics-based topics dominated (nearly 40%) the conference sessions, but the talks also included topics such as 3D vision, smart manufacturing, and Industrial Internet of Things (IIoT) - numbers which attest to the continuing strength and expansion of industrial automation in the North American market.

The Asian machine vision market continues its growth and attendance at the 2017 Korea Vision Show seemed to be in line with this as trade fair organizers recorded a 24% increase in visitors compared to last year. In order to open up the topic of machine vision to as wide an audience as possible, The Korea Vision Show was co-located with aimex - AUTOMATION WORLD; from March 29-31, 2017, The Imaging Source and reseller VIEWRUN Co. Ltd. attended the show at the Coex Center in Seoul, South Korea.

At The Imaging Source booth, 1D and 2D barcode recognition tasks featuring the 42 MP autofocus and zoom cameras were demonstrated using The Imaging Source's developer library, IC Barcode. Booth visitors also had a first look at cameras featuring the latest Sony and ON Semiconductor sensors: 33 (USB 3.0) and 33e (GigE) series cameras. Thanks to VIEWRUN for a great show!