Posts Tagged ‘ ccd’



CMOS vs CCD

Written By:
Monday, January 9th, 2012

Charge Coupled Device (CCD) and Complementary Metal Oxide Semiconductor (CMOS) both have image sensors that are used for capturing digital images, but it is the technologies that are different. They each have their own set of strengths and weaknesses that give way to various applications. It is not as if one is superior to the other, but when you speak to vendors who only specialize in one of the forms of technology they will tell you that they feel otherwise. Throughout the last five years, there have been a lot of changes that have happened from both forms of technology. There are a lot of projections in regards to the demise of the technologies that have been proven false time and time again. Both forms of technology have a bright future, but there is still a need for the framework to be enhanced in regards to both of the CCD and CMOS imagers for their strengths and opportunities that they are going to be able to offer.

CCD or CMOS

Light is converted into an electric charge that can be processed into an electronic signal through both of the imagers. Within a CCD sensor, each and every pixel’s charge has to be transferred through an extremely limited amount of output nodes, which at many times is only one. It is then converted into voltage, buffered, and sent as an analog signal from off the chip. This allows all of the pixels to be devoted to capturing light, while the output’s uniformity, which is crucial to the quality of your images, is high. On the other hand, a CMOS sensor is designed where each and every pixel has its own conversion from charge-to-voltage. The sensor will often include the use of amplifiers, noise correction and circuits that are digitized, which allow the chips to output bits of digital information. This allows the design complexity to be increased, while the area for light capturing is reduced. Uniformity is lowered because each pixel is actually doing its own conversion, but the chip could be built to need a smaller amount of off-chip circuitry for its basic operations.

CCD vs CMOS

Left: CCD ---Right: CMOS

During the late 1960s and early 1970s both of the CCD and CMOS imagers were invented. It was DALSA founder Dr. Chamberlain, who was also the CEO, which developed both of the technologies. CCD originally became the more dominant of the two technologies. It was due largely in part to the fact that it gave more exceptional imaging with the technology that was available. The imaging sensors used in the CMOS technology ended up requiring more uniformity and had smaller features beyond what the silicon water foundries were able to deliver at that time. It wasn’t until the 1990s that lithography was developed so designers could begin making their case for the CMOS imagers once again. There was now a renewed interest in CMOS that was based on the expectations of lower price consumptions, a camera-on-a-chip integration, and lower costs for fabrication due to the reusing of mainstream logic and fabricating for memory devices. Even though these benefits are only possible in theory, it will take a lot more time and money to be able to put them into practice at the same time as they are delivering a higher image quality. There is also going to be an additional process for adapting these changes into effect for the original projections.

When the imagers are designed properly you are going to get exceptional imaging performance from both the CCD and the CMOS imagers. In the photographic, scientific, and industrial applications CCD has provided the benchmarks for the performance in the highest image qualities while at the expense of the quality of images, which is also measured in quantum efficiency and noise. If you look at the CMOS imagers, you are going to find more integration, a lower dissipation of power and a smaller system size possibly. However, they often have tradeoffs that are required between the quality of the image and the cost of the device. There is really no clear line between the different types of applications that each one can serve. The designers of the CMOS technology have devoted a lot of their time and efforts into achieving high quality images, but the CCD designers ended up lowering their pixel sizes and the power requirements for their power. You are going to find a low-cost and low-power cell phone camera in the CCD technology, while the sensors in the CMOS technology are going to offer high-performance cameras for professional and industrial use, which directly contradicts all of the earlier stereotypes. The producers that have succeeded in producing the crossovers have years of experience rooted deeply in both of the technologies.

CMOS vs CCDAt the chip level the costs are very similar for both the CCD and the CMOS. Early on the proponents of CMOS were claiming that the CMOS imagers were going to be a lot cheaper. They were supposed to be able to produce the same type of high-volume wafer processing lines as the mainstream login or the memory chips, but this has not been the case. The CMOS designers had to develop specialized, optimized, and lower-volume processors that are mixed-signal fabrications in order to accommodate the requirements for good imaging. It was very similar to that of the CCD designs. It has become a very slow and expensive process to be able to provide the processes at a successful lithography node that is smaller. There is an advantage to those who have a captive foundry because they are able to maintain the attention needed by the process engineers.

There are fewer components and less power that is required to operate the CMOS cameras, however, they are still going to need companion chips in order to have the optimal image quality. This process results in a higher cost and helps to reduce the advantages that are gained from lower power consumption. The CMOS devices are a lot more complex than the CCD devices, so they are going to cost a lot more to design them. The fabrication processes of the CCD tend to be a lot more mature and optimized. As a result, it is going to cost less to fabricate and design a CCD over a CMOS imager, in regards to a high-performance application. One of the most dominating influences of the device cost is the wafer size. The larger the wafer size is, the more devices it is going to be able to produce, which means the cost per device is going to be significantly reduced. The majority of the CMOS foundries are going to offer a 200mm device, whereas, the CCD foundries tend to offer a 150mm device. The majority of the captive foundries are going to use 150mm, 200mm, and 300mm for the production for the CCD and the CMOS devices.

CMOS AnalogBeyond the pricing issue, you also have to worry about the sustainability potential. CMOS was priced below their actual costs in order to win business because they were trying to pursue a high volume and commodity applications from a limited base of various businesses. For some of those businesses, the risk that they took ended up paying off and the volume that was produced was enough to maintain a margin for viability. There were some businesses that ended up having to increase their costs, but others ended up going out of business completely. Some of the venture capitalists find high-risk startups to be interesting, whereas, imager customers are going to require a long-term support and stability plan.

There have been problems with the arrival and development of the on-chip integration, but speed is one of the areas where the CMOS imagers are able to demonstrate a considerable amount of strength. Cost advantages have been difficult for everyone to realize, but they do have a relative ease of use in the output structures that are parallel. In terms of industrial applications they are going to have great potential.

The CCD and CMOS imagers are going to remain complementary to each other. It is not so much a matter of the technology, but rather the choice is going to depend on the vendor and the application that they choose to use. There is one company that is going to remain technology neutral when it comes to the two options available to them. Teledyne DALSA’s is one of the few vendors that are able to offer real solutions with both of the CCDs and the CMOS technologies.

Even though there are a lot of differences between the two imagers, it is always going to remain in the hands of the vendor to decide which product they want to offer consumers. Everyone is going to have a different opinion of which imager is going to be the best one for them, but there is really no clear and definitive answer as to what the best option is. Take the time to go through what each one has to offer and try to make the most informed decision that you can, based on what exactly it is that you are looking for.

facebooktwittergoogle_plusredditpinterestlinkedintumblrmail

Covert Security Hidden Camera

Written By:
Monday, October 3rd, 2011

There are times when it is necessary to use a covert security hidden camera.  Security Camera King offers a full range of hidden or disguised cameras, camera units that contain their own Digital Video Recorder or DVR, and high-quality low visibility powered microphones.

What exactly is a covert security hidden camera?  It’s actually nothing more than a camera that captures digital video and audio (depending on the model) without the knowledge of the subject being recorded.  The camera can be a standard sized digital video camera or it can be a very small disguised camera like our Phillips screw-head camera.

There are basically two key factors in finding a good covert security hidden camera.  The first is that the camera must be able to function without detection from casual subjects.  In other words it needs to be hidden or disguised so well that it avoids being detected by anyone that is being recorded.  Security Camera King offers a button camera, a camera that looks just like a button that can be worn by the user.  This is a perfect example of a camera that can function without detection from casual subjects.

The second key factor for a good covert security hidden camera is that it must produce high quality video.  This is done by using the best camera components that can be obtained. Let’s take a few moments to review how a standard digital video camera works and compare the components of most covert security hidden cameras with them.

A covert security hidden camera is basically just any digital video camera.  The “covertness” of the camera is more or less how it is used and not necessarily what consists of its physical make-up.  However, in order to achieve the degree of “un-noticeability” or “covertness” needed to be a good covert security hidden camera there are many recent technologically improved components that have made achieving a “covert” state easier.

A digital video cameras works basically, by capturing the light that is reflected off the objects in its field of view.  The field of view is determined by the lens(es) of the camera.  In fact the lens’s sole responsibility is to capture all light reflection (the3 image) and focus it onto a very small sensor chip.

The sensor chip is usually very small either 1/4 inch square or 1/3 inch square.  There are two different types of sensory chips.  One is called a Charged Coupled Device or CCD and the other is called a Complementary Metal Oxide Semiconductor or CMOS.  Both have the ability to transfer light energy into electrical energy that can be measured and therefore create digital video footage.

After the light has been converted to electrical energy the camera, normally possessing one to several Digital Signal Processors or DSPs, routes this information through these chips in order to refine and digitize the information.  Once this data is done being processed including being transformed from analog to binary or digital form, it is sent to the DVR and or monitor where it can be stored on a memory device and viewed later, or viewed in real-time (live).

Some of the covert security hidden camera differences from the standard digital video camera include the lens.  Most miniature cameras use a wide angle 3.7mm lens.  The lens is so small it can be placed in a wide variety of items undetected.  From wall clocks, ink pens, speakers, picture frames and many more, Security

Camera King has a device for just about every occasion.  The lens is often called a “board lens” because it is permanently mounted on the circuit board of the camera.

Speaking of the circuit board, Integrated Chip or IC technology has enabled placing DSPs and other circuitry in a very small space.  If the camera is wireless for example, the circuit board will also contain the circuit for a transmitter.

Check out Security Camera King’s large selection of hidden cameras on our on-line catalog to see all of the different types of cameras available.

One last word of caution.  Each state has different laws governing the use of cameras and especially audio recorders without the subject’s knowledge.  Make sure you confirm you state’s laws before attempting to record anyone covertly.  This doesn’t mean that you can’t record improper or criminal activity but the planned, deliberate, covert recording may require special concessions on the part of the person recording.

 

facebooktwittergoogle_plusredditpinterestlinkedintumblrmail

DVR CCTV System

Written By:
Friday, September 16th, 2011

The Digital Video Recording Closed Circuit TeleVision system or DVR CCTV system is rapidly becoming one of the most popular security and surveillance documentation and monitoring tools in use today.  Thanks to advancements in digital technology, not only is high-quality color digital video possible, but its also economically priced, easy to install, and versatile in application.  In addition, these systems are even able to record clear videos in total darkness using infrared technology.

A DVR CCTV system is any system that captures digital video images and records them on some type of storage medium for later use.  The difference between a digital video recording system and an analog video recording system is how the video image signal is created; however this lends itself to other differences such as how the video “footage” is stored, how it is transmitted, and what kinds and types of images are available.

Let’s look at how an older analog video recording system works, then we’ll compare it with the newer digital video recording system.  Both systems have a camera that “captures” the video images and a recorder that stores those images for playback at a later time.  Each system may also use monitors to display real-time (live) video as it is captured.

Without getting too technical, an analog digital video camera contains a sensor chip called a Charged Coupled Device or CCD or a Complementary Metal Oxide Semiconductor or CMOS.  These sensors convert the image’s light energy, which is focused onto it by the lens, into electrical energy that can be measured and used to create a video image.  The images are transferred from the camera to the video recorder and monitor using a coaxial video transmission cable.

The analog video recorder records the audio and video as magnetic signals, usually on a magnetic tape.  What is actually happening is that the camera is taking several pictures per second but it appears to the human eye as smooth motion video.  This is the same way its precursor, film video works.

Film cameras actually take several film pictures or photographs per second.  Once the film is processed or “developed” a projector rolls the film from the full reel to an empty one.  As the pictures pass in front of the projector lens in rapid succession, they give us the impression of a moving video.  Since film is basically a linear storage device that can be hundreds of feet long, the term “video footage” was used to refer to motion pictures.

Since analog video is stored as a magnetic pattern, each time the recorded video is played it has the potential for degrading the signal.  In addition, time can also degrade the magnetic signal as the signal’s weaker points can fade.  Analog video is stored on a variety of formats but the most popular magnetic video tape is VHS or BETA.  The video recorder either uses a video tape loop that re-records after reaching the end of the tape or individual video tapes that must be replaced when the recorder reaches the end of the tape.

Digital video recording systems use basically the same technology to create digital video.  Onenote of interest is that digital system’s files start out as analog signals in the camera and must be digitized by the camera before leaving it.  Cameras record (with the advent of digital imagery, the term “record” is also used synonymously with “capture”; meaning that the camera “captures” light images) image light energy and transfer it into electrical energy.  However, the fundamental difference in a digital video camera is that the camera also contains an analog-to-digit converter which turns the analog video signal into a series of 1s and 0s, or in other words, digital data.

This simple change has revolutionized the security camera industry.  Since the digital video signal is now stored as a digital file, many other technological changes have taken place that have made DVR CCTV systems differ from their older analog parents.

DVR CCTV systems have become so popular that they are now the norm in the security video industry, rather than the exception.  If you are interested in learning more, check out Security Camera King’s “CCTV Learning Center.”

 

 

facebooktwittergoogle_plusredditpinterestlinkedintumblrmail

Mini CCTV Camera

Written By:
Thursday, September 15th, 2011

What is a mini CCTV camera?  Arbitrarily we can say that a mini CCTV (Closed Circuit TeleVision) camera is any camera that is smaller than the majority of CCTV cameras sold as “Standard” sized cameras.  But generally, when the term “mini CCTV camera” is used, reference is made to the small cameras normally used for covert recording.

Thanks to modern technology, anyone can own a mini CCTV camera.  Just a few years ago, these cameras were so expensive they were cost prohibitive for the individual to own, if they were even available at all.  Today, not only are they affordable but they come in a wide range of types, each designed to satisfy a specific purpose.

To understand how this is possible, let’s take a look at the technology behind a typical contemporary digital video camera.  Most of today’s video security systems consist of three basic components:  Camera(s); Digital Video Recorders or DVRs; and Monitors.

Here is how an average digital video security system works.  The camera captures the video image and sends it to the DVR where the data is saved as a digital video file.  Actually, this file can be viewed live on the monitor and/or saved on the DVR for later viewing or archiving.

The key behind the mini CCTV camera lies in how the camera captures the video images.  Digital video cameras use an integrated circuit sensor chip to transfer light energy into electrical energy.  There is usually one of two sensor chips used; either a Charged Coupled Device or CCD or a Complimentary Metal Oxide Semiconductor or CMOS.

These sensor chips come in a range of sizes with the larger sizes usually producing a larger higher quality video picture.  Most miniature wireless security cameras use a 1/4 or 1/3 inch CCD or CMOS chip, so the camera can be incredibly small.  Of course, another contributor to their small size is the incredibly small, integrated circuits that prepare the video data and send it via an on-board transmitter (wireless) or via a video transmission cable such as RG59.

These 1/4 or 1/3 inch sensor chips usually provide a minimum 380 TVL high resolution black and white or color picture.  That’s a pretty good size video for a camera with a lens the size of a pin head.  In addition, these miniature cameras also employ the use of wide angle lenses that provide an extended field of view for the camera through the small opening.

The mini CCTV camera unit itself can be incredibly small as well.  Since the camera is so small and light, it can be mounted almost anywhere.  Better yet, for more truly covert recording needs, the camera can be imbedded within another object without anyone ever detecting the camera’s presence.

These cameras make great security cameras because you can monitor your surroundings without anyone realizing a camera is present.  This can be very useful when you suspect you may have an unauthorized individual tampering with or stealing your possessions.

Security Camera King offers a huge variety of different types of miniature wireless security cameras.  Here’s just a partial list of some of the models that we offer:

The Button Cam – It takes the place of a shirt button and it even includes five extra buttons so they will match up.
The Screw Cam – This camera looks like an ordinary Phillips head type screw.
The Wall Clock Camera – It looks like a typical office-type wall clock however in addition to the functioning clock, a camera is packed inside.
Desktop Speaker Cam – Functioning desktop speakers with a miniature wireless security camera hidden inside.
Exit Sign Camera – Appears to be a normal indoor “Exit” sign.  No one would suspect a camera is mounted inside.
Stuffed Toy Dog Baby Cam – This camera comes with a handheld LCD monitor and also monitors audio as well as video.  Although it does not record video or audio, it helps you keep a watchful eye on your baby without disturbing him or her.
Vanity Mirror Camera – A double sided vanity mirror with a camera inside.

Most miniature wireless security cameras come with power supplies or battery packs and Security Camera King includes a free 2.4 GHz receiver with most mini CCTV cameras.

 

 

facebooktwittergoogle_plusredditpinterestlinkedintumblrmail

Infrared CCTV Camera

Written By:
Thursday, September 15th, 2011

Infrared CCTV cameras are becoming one of the most popular types of security/surveillance cameras for residences and commercial applications alike.  Before purchasing an infrared CCTV camera it’s important that you are familiar with some of the terminology and functions associated with this specialized aspect of a CCTV security system.

Most Closed Circuit Television or CCTV cameras today are digital cameras.  Basically, they take pictures or video much the same way as a personal digital camera or camcorder.  These cameras operate by allowing light to penetrate through an iris or variable opening, a lens, and then strike a Charged Coupled Device or CCD or a Complementary Metal Oxide Semiconductor or CMOS.

The iris is basically like the pupil of an eyeball; when there is too much light the iris makes the opening in the lens very small so as not to “flood” the CCD with light.  When there is very little or no light, such is the case for night vision security cameras, the iris is at its maximum opening to allow as much available light as possible to strike the CCD.

The chief purpose of the lens is to keep an image at a certain distance in focus.  Various lens sizes can be used to achieve focus ranges from just a few feet to several hundred.  If the lens is rated with an “F-Stop” the lower the number for night vision purposes is better because it means it does not absorb much of the light passing through it.

The key to an infrared CCTV camera is the CCD or CMOS.  CCDs and CMOSs work by converting light into electrons.  These electrons have a charge which can be monitored and used to produce a digital image.  Both sensors are inherently sensitive to infrared (IR) radiation.

There are basically two types of security cameras used as night vision security cameras.  It’s important to understand the difference between the two.  One type is also called a day/night camera and the other is an IR camera.

Day/night cameras produce color images when sufficient light is present.  These cameras have very sensitive CCD or CMOS chips that allow the camera to process light into an image at very low light intensity.  Light intensity is normally measured in units called LUX.  In full daylight (but not direct sunlight) an average LUX reading ranges from 10,000 to 25,000 LUX.  By contrast, a full moon on a clear night in non-tropical geographical locations produces about .27 LUX.  Many day/night cameras can produce clear images at less than 1 LUX.  In fact some day/night vision security cameras’ specifications indicate sensitivities as low as .0014 LUX or less.  However, day/night cameras must have at least some available light to produce an image.  They cannot produce an image in total darkness or 0 LUX.

Night vision security cameras that can produce images in 0 LUX or no-light conditions are infrared CCTV cameras.  These cameras can “see” infrared radiation in the 700 – 1400 nanometer wavelength range known as “near infrared.”  The human eye cannot see this wavelength of electromagnetic radiation so any “near infrared” light is virtually invisible to our eyes.

Infrared CCTV cameras using IR technology illuminate their target area with infrared light.  This light is provided by light emitting diodes or LEDs that are placed around the lens of the camera.  The stronger the LEDs and the greater number of LEDs placed around the camera lens determines the effective range and field of vision of IR cameras.  In essence, the LEDs are actually providing a spotlight on the target area but because the light is the near infrared type we (humans) cannot see it.

Infrared CCTV Cameras using IR technology produce a black and white or monochromatic image.  This radiation is outside the visible color spectrum therefore the images are not in color.  However, the clarity and contrast is just as sharp as normal color images.   Also, the range of the infrared night vision security camera is limited by the infrared light produced by the LEDs.  Most premium IR cameras have an effective operating range of up to about 150 feet.  It’s imperative to know the specification for IR range when purchasing an IR camera as a camera with a very short range would be useless for monitoring an area 100 feet from the camera.

Knowing a little about the two types of night vision security camera can help you make the right choice for your needs.

facebooktwittergoogle_plusredditpinterestlinkedintumblrmail