Sony has developed a technology to lower the cost of an image sensor supporting both visible and near-infrared lights.
Typically, to take an image using visible light, a filter that blocks near-infrared light is used in front of a sensor by using a movable mechanism. Sony says it has eliminated the mechanical filter by using a different color filter.
Normal color filters consist of three colors: red (R), green (G) and blue (B). And G is used for two pixels in consideration of the sensitivity of a sensor. In other words, color display is realized by four pixels. And this repetitive pattern corresponds to each color of an image sensor.
Sony replaced half of G with white (W). By using data of the three primary colors in addition to W to perform data processing, it becomes possible to remove only near-infrared light signals, Sony said. As a result, an image can be taken by using less-deteriorated visible light without a filter that removes near-infrared light.
However, the amount of G input signals is reduced, possibly lowering image quality. But this is made up for by image processing.
The new technology enables existing image sensors to take an image using not only visible light but near-infrared light just by replacing a color filter and image processing software.
The new technology was announced last month at Infrared Array Sensor Forum 2015.