3 Chip EM-CCD

High Sensitivity Cameras

Surveillance technologies have evolved to meet the demanding security and monitoring needs of businesses and transportation hubs. NEC has developed a High Sensitivity Camera (HSC) with the ability to capture video images in fully dark environments. This high performance camera is capable of recording action with full-color clarity in full darkness, such as starlight and new moon lighting conditions.

Cameras with the CCD (charge-coupled device) chip are designed to work in low light conditions to produce a high dynamic range image with few light photons. Typically used in scientific applications, NEC has designed its HSC to serve as a nighttime surveillance tool in a variety of applications, including securing facilities and utility plants, as well as tracking illegal activities at sea or in seaports.

There are several types of cameras on the market that are positioned as providing high sensitivity video, however the lighting conditions required to capture video vary greatly for each camera. For example, cameras using only one general CCD (charge-coupled device) chip are considered “high sensitivity,” but they still require the brightness of at least a full moon. At the other end, infrared cameras are capable of capturing images in complete darkness, however very few lenses can support the technology and the image is only black and white.

Lighting Range Requirements of CCD CamerasLighting Range Requirements of CCD Cameras

Features

  • 3 EMCCD (electron-multiplying charge-coupled device) chip creates a high sensitivity image with efficient use of light
  • Full-color video capture in full darkness, such as starlight and new moon lighting conditions
  • Excellent nighttime surveillance tool
  • Fully automatic white balance
  • Automatic sensitivity control

Technical Highlights

3 EMCCD

NEC's HSC utilizes 3 EMCCD to regenerate the color by using three chips of electron-multiplying charge-coupled device (EMCCD).

A CCD converts light into electrons through the photo diode and transfers it to the electrical signal. To increase sensitivity, the electrons are charged to amplify the electrical signal. But the charging makes the image lag, like a tail, and amplification of the electrical signal also gains noise. Both the electrical signal and the image gain sensitivity, but there are some challenges to regenerate high quality images.

Signal Amplification of Conventional CCD CameraSignal Amplification of Conventional CCD Camera
One chip CCD

When only one CCD is used, the light is split into three primary colors through the filter. With one CCD, the light absorption of the filter and its mosaic arrangement makes it difficult to create a clear color video.

Three chip CCD

With three CCDs, like NEC's HSC, the light is split into three primary colors through a prism instead of a filter, and creates a high sensitivity image with efficient use of light.

In the case of EMCCD, an Electron Multiplying (EM) register in the CCD multiplies the electron signal before it is transferred to the electrical signals. The video image, even a weak optical image in a dark location, can regenerate in high quality without noise by increasing the electron signal.

Signal Amplification of NEC High Sensitivity CameraSignal Amplification of NEC High Sensitivity Camera

Unlike a conventional CCD, an EMCCD is not limited by the readout noise of the output amplifier, even when operated at high readout speeds. This is achieved by adding a solid state Electron Multiplying (EM) register to the end of the normal serial register, which allows weak signals to be multiplied before any readout noise is added by the output amplifier that may render the read noise negligible.

Fully Automatic White Balance Function

Different sources of light have different “temperatures,” which affects the color accuracy of the images. The full automatic white balance (FAW) function available on NEC's HSC automatically adjusts the white balance to produce videos with colors that are as close to the live image as possible.

Automatic Sensitivity Control Mode

According to the brightness of the object, the Automatic Sensitivity Control (ASC) mode available on NEC's HSC automatically adjusts the sensitivity for electric signal gain, pixel addition, digital gain, accumulation time, and shutter speed.

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