Industrial machinevision

Historically a fully installed machine vision system could have cost between $500,000 and $1,000,000. Now, thanks to technological advances and the volume production of cameras costs have come down, and an investment of $50,000 and $100,000 would get you a high-end vision system. The cameras of today come for a third of the price and offer five times higher performance and bandwidth. Smaller manufacturers, in many industry segments, are now able to justify the ROI on a system in shorter time periods and are seeing the value in adopting machine vision systems.

Cognex insight

Using this method, we can freeze motion better for cutting in our plates. However, there is a caveat one must consider. At narrower shutter angles, a subject in motion can appear jittery on screen. This is the strobe effect and can be very disconcerting for the audience. For this reason, choose narrow, skinny shutter angles with caution.

As a filmmaking term, shutter angle references the basic function of film-based motion picture cameras. In order to explain what a shutter angle is, we must first discuss the mechanics of the film-based camera system. Traditional film cameras create images using photographic emulsion as a recording medium, and this requires a shutter mechanism to control exposure time. There is a basic correlation between frame rate and the rotation speed of a camera’s mirror shutter. It is important to note that much of the way a contemporary digital cinema camera operates comes from the rudimentary function of film cameras and their film transport systems.

The automotive industry is a very large consumer of machine vision, using thousands of cameras along their production lines, each camera doing specific tasks and error-proofing at every step of automation. Historically, machine vision was used as a final quality check at the end of production. The goal today is to catch the error or defect as early as possible so as not to waste resources, particularly in high-speed and high-volume production setups. In this age of 100% quality inspection, error-proofing at every stage allows for fewer production jams and more productivity, while avoiding waste of material and time.

Active Inspection provides solutions using vision systems including aerial, line scan, 2D and 3D, color, monochrome, visible spectrum, short wave, infrared, and ultra.

Visioncamera system

Designed specifically for quality professionals in the manufacturing industry, this session aims to equip you with the tools and strategies to transform your role and your organization's approach to quality.

Yes, the one gap we see is that typical system integrators tend to use off-the-shelf cameras that come with their own set of tools. The available solutions tend to be a selection of ready components and existing tools. At the most, they customize panels and electrical and add a mechanical converter. But in terms of core machine vision and software, their contribution is limited, resulting in a limited solution.

Vision systemsintegration

The term electronic shutter describes the electronic process of controlling exposure time in a digital cinema camera using a CMOS imaging sensor. Many modern digital cinema cameras can adjust the equivalent of an electronic shutter angle. In typical cases, the camera does not have an actual rotating mechanical shutter. Rather, the adjustment controls the amount of time that the electronic image sensor is energized with the light from an exposure to record video. Because there is no need to mechanically advance film in a video camera, the shutter can be adjusted to fully open — 360 degrees — to stay open for the entire interval period. In this way, we can use electronic shutter angle as an exposure balancing option outside the traditional variables of F-stop and ISO described in the exposure triangle.

Glen Ahearn is a sales and applications support manager at Teledyne DALSA. He has been in the vision industry for 32 years, and worked for companies who pioneered developments in the vision industry. For more information, visit www.teledynedalsa.com.

For a company like Active Inspection, with a strong machine vision and software background, we can fill in some of the gaps. Using custom algorithms or custom development we are able to provide better solutions. Another factor that is coming into play now is the progress in camera technology. Twenty years ago, the camera was a stand-alone component that took a picture of a part and sent a signal to a receptor to register whether the part was good or bad. Today we are dealing with complex integrated systems. The information comes from a level two control system, where detailed information such as hours of production, particulars of the parts in production, etc., are relayed.

Sponsored Content is a special paid section where industry companies provide high quality, objective, non-commercial content around topics of interest to the Quality audience. All Sponsored Content is supplied by the advertising company and any opinions expressed in this article are those of the author and not necessarily reflect the views of Quality or its parent company, BNP Media. Interested in participating in our Sponsored Content section? Contact your local rep!

Does shutter angle matter when shooting using a green screen? Typical motion blur can create headaches for VFX artists doing chromakey replacements. In these circumstances, a crisper image helps to cut a cleaner matte. High effective shutter speeds freeze more subject motion, reducing image blur around the edges of elements.

The frequency of the flicker relates to the speed at which each frame is moved into position, exposed or projected and then advanced through the system on a reel. This persistence of vision allows for the film-like quality demonstrated by digital cinema cameras that capture video images via 24p.

We work with these clients to develop new, custom solutions for them or try to evaluate what is feasible. These are tougher problems that typically do not fall into very standard system integration. Because we are not a “standard system integrator” and are able to provide a lot of software development capability, we are able to fill in a lot of gaps. There was a time when we wrote software from scratch, but now our goal is to license or purchase as many of the components that are available. At the same time, we have the capability to go deep into these gaps and fill them with some custom solutions.

Going up the chain, we can even create interfaces through web technology or mobile technology where a plant manager is able to access some amount of this quality data. Today, quality data is accessible to different levels in the organization, delivering the information they need in a timely manner.

The movement consists of a motor transport system that uses a series of sprockets on a drum system. This drum effectively pushes or pulls a load of film through the camera–across the gate ⁠— a rectangular opening that exposes film to light.

Active Inspection has been in business for over two decades designing and developing industrial machine vision and machine learning solutions. Alongside supplying a suite of standard vision systems, they also build custom vision systems to provide solutions for more complex problems.

Three decades ago, when I started in the industry, vision systems, even basic inspection systems, were not a necessary component of the process, rather it was added as an auxiliary piece. Today, complex machine vision inspection systems have become a key component of the manufacturing process, to a point that if the vision system fails or is not functional, production is stopped until the problem is fixed. With manufacturing happening at such high speeds with massive outputs, a small defect that is not caught on time can prove very costly.

Steady and consistent quality inspection plays a pivotal role in the manufacturing process. An increasing number of manufacturing plants are being fitted with multiple machine vision inspection systems to cover the entire production chain, ensuring higher-than-ever levels of quality. The automated exchange of consistent information between these different systems in a manufacturing environment is the essence of system integration, allowing for improved productivity and quality, reduction in cost and waste, and overall innovation. In my role as sales and application support manager, I work with many of the systems integrators who rely on our products to support their development of vision systems. We sat down with Dr. Arun Dalmia, founder and president of Active Inspection, a systems integrator based in Grand Rapids, MI, to ask him some questions on how system integration has helped his clients build robust and sustainable manufacturing processes and how the role of systems integrators is evolving.

About one-third of Active Inspection’s efforts are dedicated to R&D. We work with some large automotive and pharmaceutical companies who are trying to push the technology envelope. They present us with common problems that do not need to be fixed in short term, but they are interested in a solution in the next two to three years to better streamline their production process.

The camera uses a rotating shutter to control the interval at which light can strike the film when moving through the open gate. Think of the shutter as a disk, like a pie with a slice cut out. That slice can be adjusted in size. The bigger the slice, the more time light has to strike the film plane during exposure. The shutter must be timed so that, as each new frame of film is presented in the gate, exposure happens in a fraction of a second. At this time, a new frame advances into the gate, while the previous frame moves through the remainder of the movement toward the take-up reel inside the magazine. Projectors implement a similar process when projecting a film, only it emits light rather than collecting it.

Given the frame rate and the rotation of the mirror/shutter assembly, we can derive the effective shutter speed. Since the mechanism has two conditions ⁠— open and closed ⁠— divided equally, the effective shutter speed becomes a factor of two times the frame rate. In essence, at 24 fps, our camera’s effective shutter speed correlates with 1/48 second when paired with a 180-degree shutter angle. At 30 fps, the effective shutter speed is 1/60 second. At these speeds, an appropriate amount of inherent motion can be frozen, with a minimum amount of image blurring. This occurs as a subject moves in correlation to the shutter opening and closing during exposure. Photographers must pay particular attention to this principle, as it dictates how clear a subject appears in a single captured image while that subject is in motion. The faster the shutter speed, the clearer moving subject appears.

Visionsystem integrator

One industry that adopted automated inspection and automation later is the food processing sector. This is a labor-intensive industry, but we are now seeing that they are opening up to adopting machine vision or inspection automation more and more.

In the interval, while the shutter is rotating in and out of position, exposing each new frame, a rotating mirror, moving in sync with the shutter, allows for direct viewing of the image through the lens via a beam splitter. As the mirror alternates with the shutter, the image appears to flicker inside the viewing system of the film camera.

There are four essential components of a film transport system in traditional cinema cameras: a movement, a gate and a rotating shutter with a rotating mirror. Each of these components must function in synchronization as film moves through the camera. Its journey takes it from the film magazine through the gate, where it is exposed to light. Then the film gathers back in the magazine for removal.

Visionsystem camera inspection

So, we choose different frame rates for film and video because of the effects that result from high and low fps when played back at standard rates. High frame rate footage appears slowed down when played back. This is because the camera captures images at rates double, triple or greater than the normal 24 fps. At recording rates of 48 frames per second and higher, images slow down when played back at 24p. Conversely, images recorded at rates slower than 24p will result in exaggerated motion that appears faster than normal when played back at 24p. With a shutter angle of 180 degrees, the effective shutter speed occurring at 48 fps is 1/96 second. At 60 fps, the effective shutter speed is 1/120 second. At 100 fps, the effective speed becomes 1/200 second.

In each of the above situations, in order for the shutter disk to be clear of the gate for exposure at high frame rates, it must be in sync with the fps. Thus, the higher effective shutter speed.

Videomaker is always looking for talented, qualified writers. If you have a great idea you’d like to share with our readers, send it to editor@videomaker.com.

IVS Industrialvision SystemsLtd

With manufacturing happening at higher and higher speeds (up to two, three and five parts per second), our systems are able to capture between 500 to 2,000 frames per second, something even the human eye cannot register. With AI replay, which is the ability to scroll back the video on the production process, the information is invaluable. We can create a large buffer and go back anywhere between five minutes to five hours of the recording, analyze frame by frame and pinpoint exactly where in the process the problem occurred and what caused it.

Cognex

After the initial assessment, we move to provide a plan for an end-to-end solution, picking the right technology components—the camera, the lighting, controls, software libraries, interfaces, etc. We provide a proof-of-concept, a feasibility study, to show the components we have chosen would work for them. Thereafter we move on to implementing, installing, training the customer, and providing the product lifetime support. Our company and our team of engineers are very responsive to our customers. We work very closely with them to ensure that all their needs are met, which I believe is a very critical part of the integration process.

When image blur must be curtailed — as in shooting green screen elements — but the frame rate stays at 24 fps for the sake of sound recording, how do we calculate the necessary shutter angle?

Our first interaction with a new customer centers around understanding their requirements and needs, and more importantly discovering the problems they face with their current setup. Figuring out which part of the problem we can effectively solve is the next order of business. We analyze to see if it is logical and realistic to solve the problem they are trying to solve, based on the technology, the hardware, the software, and even their budget limitations. Being transparent and honest about how effective the solution will be given these constraints is essential.

The strobe phenomenon can be an effective tool to imply moods or tones like adrenaline. The D-Day scene from “Saving Private Ryan” (1998) uses the effect effectively. Director Steven Spielberg and cinematographer Janusz Kaminski used the “skinny” shutter effect to accentuate the feelings of anxiety, fear, and adrenaline soldiers experienced in the WWII invasion of Normandy.

Partner with us to reach an enthusiastic audience of students, enthusiasts and professional videographers and filmmakers. Click here to contact a sales representative and request a media kit.

We provide a lot of our expertise to line scan applications. We work with a wide variety of industries from automotive to pharmaceutical to continuous/web inspection for film, plastic, and paper, to food processing. Our work in deep learning applications is growing too. Where classic image processing and machine vision tools fail, we find deep learning is able to provide good solutions. We are also relying more on high-speed video recording and diagnostic systems.

Some industry segments widely use machine vision on a routine basis, and others are still to be introduced to the technology. But definitely, awareness is building about its usefulness and many more industries are adopting vision systems as a part of their manufacturing and quality control processes.

When integrated with a PLC, the system can trace the number of parts that were made that day and register the number of rejected parts from that batch. At a later date it will be possible for the system to trace back the data from that day and see why the parts were rejected, what was the problem, what the rejected parts looked like, and even details about their size and measurement. This level of detail can be useful to a line supervisor to study the defects and rectify the cause of the problem.

The frame rate is the timed interval the film transports through the gate. We use two primary frame rates when recording with film or digital video. Film cameras traditionally record at a rate of 24 frames per second (fps). At this rate, the human eye perceives motion in a rapid succession of individual images projected onto a screen. Subject motion appears normal, with a minimum of image blur, while lip flap appears to match the audio we hear associated with the images. Video systems record and playback at a slightly quicker 30 fps. This is related to the field scanning rate of television, which happens in odd and even lined intervals inside of 1/60 of a second. This field recording technique is known as interlacing.

In each circumstance, a shutter angle is associated with the given fps. At 24 frames per second, the standard shutter angle for film cameras is 172.8 degrees, as it relates to rotation. At 30 fps, the associated shutter angle for video playback is 180 degrees. Since the difference in exposure compensation between the two angles is so minimal, the 180-degree setting is considered normal and is often used interchangeably between the two frame rates.

If a faster shutter speed comes from a narrow shutter angle, then the opposite is also true. At wider shutter angles, effective shutter speeds slow down. This results in a dreamy or smeared look to images in motion within the frame. Photographers refer to this as “dragging” the shutter. Objects in motion will blur dramatically with regard to their apparent motion. A classic example of this is the scene from Wong Kar-wai’s “Chungking Express” (1994), where the hero chases his adversary through a busy Chinese market.