Quality Gap Closes
It’s only been in the last few years that the limitations of the technology have sufficiently been overcome to make CMOS a viable alternative to CCD. The quality gap between images that are being captured with CCD sensors and images being taken with CMOS sensors is narrowing rapidly.
That is especially true as digital camera resolutions climb. CMOS sensors don’t suffer from the decrease in the signal-to-noise ratio as resolutions increase. That means higher resolution digital cameras can be produced without having to significantly increase the supporting electronics.
One of the reasons that CMOS is finally taking off is that there are a large number of corporations, educational institutions and governmental agencies working on the technology. With more than 60 organizations working on CMOS development, the size and quality of the images that those sensors can capture are increasing rapidly.
X3 Marks the Spot
One of the companies on the cutting edge of CMOS development is Foveon, which developed the X3 sensor chip. In some respects, the X3 is revolutionary. It was the first full-color image sensor that captured red, green and blue light at each individual pixel position. Instead of using color filtration to capture RGB color values, the X3 is able to capture all three primary colors simultaneously.
It can do that because it has three photo-detectors at every sensor location, making it possible to capture full color images, without having to use a color mosaic filter. CMOS sensors are able to do that without the complexity, and cost, of some CCD systems.
Foveon was able to achieve the multi-color capture capabilities through the specific properties of silicon, which absorbs different light waves at different depths. Each X3 sensor consists of three photo-detectors located at different depths. Each detects the absorption of the red, green and blue light that has penetrated the silicon to that specific depth. Blue light is absorbed near the surface, green light is absorbed farther down and red light is absorbed even deeper.
The individual photo-detectors convert the absorbed light into three signals. Those signals are converted to digital data, which is then optimized through software. According to the company, the X3 CMOS image capture and optimization process results in higher quality and sharper images, as well as better color. It also eliminates the color artifacts that can be a problem with CCD sensors.
That is especially true as digital camera resolutions climb. CMOS sensors don’t suffer from the decrease in the signal-to-noise ratio as resolutions increase. That means higher resolution digital cameras can be produced without having to significantly increase the supporting electronics.
One of the reasons that CMOS is finally taking off is that there are a large number of corporations, educational institutions and governmental agencies working on the technology. With more than 60 organizations working on CMOS development, the size and quality of the images that those sensors can capture are increasing rapidly.
X3 Marks the Spot
One of the companies on the cutting edge of CMOS development is Foveon, which developed the X3 sensor chip. In some respects, the X3 is revolutionary. It was the first full-color image sensor that captured red, green and blue light at each individual pixel position. Instead of using color filtration to capture RGB color values, the X3 is able to capture all three primary colors simultaneously.
It can do that because it has three photo-detectors at every sensor location, making it possible to capture full color images, without having to use a color mosaic filter. CMOS sensors are able to do that without the complexity, and cost, of some CCD systems.
Foveon was able to achieve the multi-color capture capabilities through the specific properties of silicon, which absorbs different light waves at different depths. Each X3 sensor consists of three photo-detectors located at different depths. Each detects the absorption of the red, green and blue light that has penetrated the silicon to that specific depth. Blue light is absorbed near the surface, green light is absorbed farther down and red light is absorbed even deeper.
The individual photo-detectors convert the absorbed light into three signals. Those signals are converted to digital data, which is then optimized through software. According to the company, the X3 CMOS image capture and optimization process results in higher quality and sharper images, as well as better color. It also eliminates the color artifacts that can be a problem with CCD sensors.
posted by eecalvin at
5:20 PM
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