The future of CCD image sensors: Are we seeing the end of an era?

30/03/2015
Sony recently announced its intention to close its 200 mm CCD wafer line in Kagoshima and to stop the manufacture of the majority of Sony’s industrial CCD (charge-coupled device) sensors.

Mark Williamson, Director – Corporate Market Development of Stemmer Imaging, explains how machine vision users and his customers are affected by this decision.

Mark Williamson

Mark Williamson

Question: CCD sensors have been the key enabler of the imaging and machine vision market, with Sony being the largest vendor of CCDs to this market. What has driven this decision?

Williamson: Before the CCD arrived video cameras were based on tube technology which were free running only and came from the broadcast industry. When CCD technology launched it became possible to add specialist features in cameras to enable triggering and hence the ability to synchronise to the production line. This enabled the explosive growth of industrial vision which developed into the industry we know today. However, while Sony CCDs have the largest market share in industrial imaging, the biggest market for image sensors has been larger markets such as consumer cameras, mobile phones, CCTV and broadcast. The importance of the CCD to mankind was recognised by a Nobel prize in Physics in 2009. In the last few years there has been a big shift from CCD to CMOS in these high volume markets which has left the CCD wafer line very underutilised even with the high number of machine vision sensors sold. This makes the factory no longer financially viable.

Question: Historically CCD sensors have outperformed CMOS (complementary metal-oxide semiconductor) sensors in terms of image quality. Will Sony’s decision reduce the availability of high image quality sensors?

Williamson: Absolutely not, CMOS has traditionally had a reputation for lower image quality, however recent sensors have surpassed the image quality of Sony CCDs in terms of noise and dynamic range. This, coupled with the numerous advantages of CMOS sensors such as speed, lower power consumption, less support electronics and the elimination of tap balancing is the natural evolution of technology. The higher end CCDs from ON Semiconductor (formerly Truesense and Kodak) and the full frame CCDs used in professional photography from Teledyne DALSA are still available for high end applications although over time CMOS will affect this market segment also.

Question:  Are there other advantages of CMOS over CCD technology?

Williamson: From a manufacturing point of view CMOS sensors can be built on standard wafer lines which utilise mainstream manufacturing capacity and competition. From a technical point of view the ability to mix sensor and support circuits on to one device simplifies camera design and allow additional features to be integrated. Multiple regions of interest, and linear scaling of frame rate versus readout region provide application flexibility and high dynamic range modes, additionally the reduction in oversaturated image bleed makes the cameras more tolerant of changing illumination.

Question: What is the share of CCD cameras compared to CMOS cameras Stemmer is selling today?

Williamson: In 2010, 22 % of cameras we sold were based on CMOS sensors. This has risen to 58 % in 2014 with 32 % of cameras using Sony CCDs and the remainder other high end CCDs. With nearly all new camera designs using CMOS the prediction is that in a further 4 years the natural shift would make the CMOS market share approximately 80 %.

Question: What is your expectation of how Sony’s decision will change that ratio in the future?

Williamson: Although Sony has announced the closure, production will not cease until 2017 with the last deliveries in 2020 or even later, depending on the sensor model. This time scale is designed to follow the natural declining trend which is expected to continue and maybe slightly accelerate. With the attractive price: performance ratio of new CMOS cameras new designs are expected to use CMOS anyway.

Question: What are your plans with regards to the announcement?

Williamson: While Sony CCD availability will continue until at least 2020 the camera manufacturers will need to commit to quantities much earlier. Each camera manufacturer may choose to take a different approach, to commit to stock sensors or asking customers to make future commitments. Stemmer Imaging are liaising with all our camera manufacturers to agree their policy and we will communicate this policy if it has any effect on availability to customers. Some models will be available even after 2020.

Question: What is your advice for imaging and machine vision integrators and users that have used CCD cameras in the past?

Williamson: If you build an OEM product that utilises a CCD camera we believe there is no immediate need to change the camera. If there is any risk of your particular camera being made obsolete we will inform you normally with 6 months notice under our End of Life programme. However when selecting a product for a new application we would recommend selecting CMOS sensor based cameras as availability will be longer and also the price: performance ratio will be better. If CCD capability is important remember CCD sensors are available from other companies.

Question:  Are Sony leaving the machine vision sensor market by discontinuing its CCD sensors?

Williamson: Sony have been innovating with CMOS sensors for some time and are investing significantly in expanding their CMOS wafer production capability. They have announced their first CMOS global shutter sensor family under the Pregius name aimed directly at the imaging and machine vision market. The first model named IMX174 is already shipping in a number of our cameras and outperforms the Sony CCD equivalent. With a clear roadmap of further models we will still see Sony sensors in the machine vision market.

Question: Which other players are in the imaging and machine vision sensor market?

Williamson: Over the last 10 years we have seen many small companies launch CMOS image sensors addressing the low cost or high speed market where CCDs could not compete. In recent years a number of these have become significant providers through a combination of innovation and acquisition. While Sony has been the dominant supplier of CCDs to the imaging and machine markets this dominance is not evident with CMOS giving more market choice . Key players besides Sony are ON Semiconductor, CMOSIS, e2v and Teledyne DALSA. Our direct relationship with Teledyne DALSA allows us influence over their sensor strategy so customer needs are valuable input.

Question: With so many manufacturers and sensors how do I choose what?s right for my application?

Williamson: Like any product each manufacturer’s design has advantages and disadvantages. Stemmer Imaging has an in-house EMVA 1288 camera testing facility which is used to characterise cameras and hence the sensors beyond the spec sheet. With this capability, our immense knowledge of sensor and camera technologies and access to the largest number of camera manufacturers and possibly all sensors relevant to our market we are well placed to advise customers as to the sensors and cameras that are best suited to their application. When you are ready to migrate to the new generation of CMOS sensors we are here ready to assist.

• See also: What is the difference between CCD and CMOS image sensors in a digital camera? (How stuff works!)

Instruments down the drain!

18/11/2013
CCTV hire supports excellence in drain services

With more than 40 regional drain cleaning service centres across Britain, Metro Rod provides a 24 hour service to anyone with blocked or damaged drains, pipes, toilets, sinks etc. To support this capability, the company and its franchisees maintain a fleet of the latest equipment such as tankers, high pressure jets, excavators, pipe liners and CCTV surveying equipment.

InpsectionFamilyTo ensure a fast and effective response to all customer requests during periods of peak demand, many of the franchisees take advantage of Ashtead Technology’s equipment rental fleet. For example, Ryan Davis is the owner and manager of the Metro Rod franchise for London East Central. With many years of experience managing Metro Rod in this area, Ryan has established a highly trained team of engineers supported by heavy investment in equipment such as a 3,000 gallon tanker and the latest CCTV drain inspection equipment. However, Ryan says: “Occasionally we need to undertake drain surveys in different locations at the same time, and we also receive enquiries that necessitate more specialised inspection cameras, so if our own equipment is unavailable, it is very useful to be able to hire the best instrument for the job.

“Ashtead Technology maintains a comprehensive fleet of the latest inspection tools including robotic camera crawlers and push-rod cameras and videoprobes, so we are able to quickly supplement our own equipment as and when we need to. This helps to ensure that our customers receive the best service possible.”

Metro Rod’s customers range from domestic customers with a blocked pipe or drain, to large water utilities that rely on a rapid response to any problems in the water and wastewater distribution network. In addition to emergency response, Metro Rod also provides routine preventative maintenance services to a wide range of organisations. For example, the south London franchisee provides ongoing service to the Wimbledon Lawn Tennis Club, including a major service in June, immediately prior to the Championships.

The ongoing operation of many industrial processes relies on the effective discharge of effluent, and any problem in this waste stream can limit or even halt production. Metro Rod’s national network of local teams means that the company is able to provide a fast and effective solution to blockages and related problems in pipes, drains and culverts.

“This ability to respond quickly to customer requests is a key feature of our business,” says Metro Rod’s Marketing Manager Ieuan Nicholls. “Our teams are highly trained and experienced, and they are equipped with the latest equipment to ensure prompt resolution of any problems.

“The facility to rent inspection equipment during periods of high demand means that we can ensure that we have the right kit on the ground for every job.”

Ashtead Technology’s Jay Neermul agrees: “It would not make financial sense for any company to purchase the volume of inspection equipment required to meet the highest level of need, because, by definition, a significant proportion of this equipment would lie unused, depreciating for much of the time.

“We have invested in our wastewater inspection fleet to meet increased demand, and have recently ordered more of the latest crawler units and pushrod cameras. We are therefore delighted to be able to partner with Metro Rod’s teams to ensure that they have exactly the right kit, wherever and whenever they need it.”