DPS pixel digitization system from Pixim. Cameras with Pixim matrix.
Pixim's patented DPS (Digital Pixel System) technology represents a fundamental breakthrough in imaging technology. Based on technology developed at Stanford University in the 1990s, Pixim has created a device that produces and processes high-quality images with improved dynamic range. Greater dynamic range significantly improves the quality of images that contain both light and dark areas.
The essence of the DPS invention is to introduce an analog-to-digital converter (ADC) to process each pixel of the light-sensitive sensor. The ADC converts the light signal into a digital value directly at the point of image formation, thereby minimizing signal loss and mutual influence of matrix elements, and making possible methods for significantly reducing noise. Since the data is implemented in digital format, various methods of digital signal processing can be used for optimal image reproduction.
The essence of DPS
To achieve unmatched image quality, Pixim's DPS technology uses an information acquisition technique known as multi-sampling. Within a single field (which in video changes 50 or 60 times per second), each cell (pixel) is independently sampled multiple times without destroying its charge. The imaging system determines the optimal time to sample and store the pixel information before the cell is saturated and can no longer hold additional charge. In the diagram on the left, the light pixel is stored at time T3, the last sampling moment before 100% saturation. The dark pixel accumulates charge more slowly, so it requires additional time before being sampled and stored at time T5. The stored information (brightness, time, noise level) obtained for each cell is processed in parallel and converted into a high-quality image. This is different from other technologies, which set one common exposure time for the entire frame, and during this time, all pixels are sampled, resulting in some pixels in the image being underexposed (too dark) and some overexposed (too light). Designations on the drawing: along the ordinate axis is the percentage of converted light flux, along the abscissa axis are sampling times (typical exposure).
Eye and Brain
Pixim's first DPS-based product, the D2000 Video Imaging System, combines a digital light sensor and a digital image processor. The digital sensor and the digital processor work in the same way that the human eye and brain work together to produce the best possible image quality. Just as the brain tells the eye to dilate when entering a dark room to let in more light, the digital processor loads new code into the sensor to change not only the exposure times, but also the image acquisition algorithms that are in place. The result is the best possible image for the specific image parameters and lighting conditions.
Each Cell is a Video Camera
Because each pixel has its own ADC, and information is generated and processed independently, each pixel acts as an individual video camera. The exposure time for each pixel is adjusted to handle the unique lighting conditions of each cell in the sensor array. A DPS-based device essentially contains hundreds of thousands of individual video cameras, each generating the best possible image. These images are then combined to create a high-quality video frame or image.
As imaging technology continues to evolve toward all-digital systems, Pixim's DPS pixel acquisition system will enable high-quality images to be captured and processed in video and digital cameras.
pixim
Translation by Yuri GEDZBERG
security-bridge/articles/10/324/
Cameras based on PIXIM technology are also available to consumers on the Russian market. Here are some models.
Smartec STC-2008 color camera with PIXIM® matrix and WDR up to 120 dB
The highly sensitive color camera STC-2008 by Smartec is equipped with a 1/3-inch PIXIM matrix with a resolution of 720 x 540 pixels and is manufactured in Japan. Due to the use of PIXIM technology, this video surveillance camera can operate in a wide dynamic range of up to 120 dB and will be most effective at sites with constantly changing illumination, including outdoor conditions. The STC-2008 has a sensitivity of 1 lux, and in the frame accumulation mode up to 0.03 lux, a resolution of 520 TVL, automatic/manual white balance adjustment, AGC and a backlight compensation function, which allow it to form the highest quality image under various video surveillance conditions. At the same time, the STC-2008 can work with any lenses, the diaphragm of which is controlled by a video signal or a DC signal. Thanks to multisampling and digital video signal processing, the camera fully compensates for image distortions caused by backlighting or a bright background, sudden changes in illumination, as well as color changes in low or excessively bright light.
ZC-DW4312PHA (GANZ)
Camera module in a dome housing. CMOS matrix with PIXIM technology, 720 x 540 pixels, PAL. IR-corrected varifocal lens 3.3–12 mm.
Resolution — 520 TVL, min. illumination — 1.3 lux (F1.4). DC iris control.
Viewing angle — 89.8–23.9°. Wide dynamic range — 120 dB, 17 bit.
Power supply voltage is 12 volts DC/24 volts AC.
Thanks to the three-axis mechanism, the camera can be correctly directed both when installed on a wall, ceiling, and any inclined surface.
All control and settings are performed through the menu on the screen.
Thanks to the built-in Pixim sensor, the ZC-DW4312PHA camera produces optimal contrast images indoors, and the ZC-DWT4039PHA — outdoors. The wide dynamic range function works even in the most difficult lighting conditions and automatically calculates the ideal values for its operation to always provide a high-definition image of the highest quality.
SRD-VF540PD color dome camera with extended dynamic range based on the Pixim matrix
The video camera uses innovative Pixim/DPS video signal processing technology, which uses an analog-to-digital converter directly in each pixel of the matrix and microprocessor signal processing in real time. Two-way high-speed data exchange occurs between the signal processor and the matrix, which makes it possible to adaptively control the operating parameters of each individual light-sensitive element, thereby obtaining the cleanest and most informative image.
This technology achieves an ultra-wide dynamic range (Ultra Wide Dynamic Range – UWDR), hundreds of times greater than the capabilities of traditional cameras. Despite any changes in lighting, the camera provides high-quality images without overexposed or darkened areas.
The SRD-VF540PD working module can rotate in 3 planes, so the camera can be installed in any place and position, providing an overview of the required area.
CCWC1345 Color Video Camera (Siemens)
The CCWC1345 color video camera has a high dynamic range of 120 dB, a 32-bit DPS (Digital Pixel System), a built-in motion detector, a horizontal resolution of more than 500 TVL, an output for transmitting a video signal over a twisted pair (UTP), a sensitivity of 0.5 lux, and adjustable back focus.
The CCWC1345 uses a CMOS sensor and a Pixim D2500 32-bit DPS chipset that converts light into a digital signal from each pixel, allowing for independently optimized exposure times for each pixel. This ensures razor-sharp images and precise color matching. This chipset allows you to capture the finest details in video recording, even in low-light conditions.
The use of Pixim chips significantly expands the dynamic range of the camera, which distinguishes the CCWC1345 camera from its counterparts made using conventional technologies. The main advantage of PIXIM technology is the ability to obtain good-quality images even when working in conditions of strong illumination — where other cameras would be completely «blinded».
Outdoor camera with Pixim Camclosure IS110 matrix (Pelco)
The Camclosure IS110 mini dome has a WDR function and a built-in IR filter. The day/night mode implemented on this circuitry allows you to effectively use this camera both during the day (sensitivity 0.8 lux) and at night (0.08 lux, in SENS 8X mode up to 0.02 lux).
Using Pixim technology allows you to effectively cope with the problem of illumination at night. An example of an ideal place to use such a camera is an outdoor parking lot, where at night the illumination changes sharply (glare from headlights, etc.), and you need to inspect unlit areas.
For reliable and effective operation in outdoor conditions, this camera has everything you need: automatic diaphragm, built-in varifocal lens (3.0 — 9.5 or 9.0 — 22 mm), vandal-proof aluminum casing and a polycarbonate dome.
In addition, the model has a built-in video signal transmitter over a twisted pair, which is also very convenient for outdoor use.