Area sensor
An area sensor is a functional principle of image sensors for digital cameras ; it is used exclusively in one-shot and three-shot cameras .
Working principle
One-shot sensors
One-shot sensors simultaneously register the three basic colors of the additive color mixture (red, green and blue). The chip can only see light or dark, only black or white. Therefore, 1 filter for red, 1 filter for green and 1 filter for blue is required so that the sensors can recognize the colors. So from a 6 megapixel sensor there is only a 2 megapixel color sensor left. The rest of the image information is calculated (interpolated), but is not actually available. This results in moiré and color problems, because interpolation has its pitfalls.
Three-shot sensors
Three-shot sensors record the color values for red, green and blue one after the other, with a different color filter being used in each case. This avoids interpolation.
Special constructions
One-shot multi-chip cameras , which each use a CCD for a primary color, couple it and thus achieve a higher image resolution, represent a special, but no longer widespread design . One such three-chip model was the Minolta RD-175 digital SLR camera from 1995 (effective resolution: 1.75 megapixels).
Applications
One-shot cameras are suitable for everyday use and can also be produced comparatively cheaply.
Three-shot cameras are used as high-quality studio cameras, but the motifs must be motionless due to the multi-phase image scanning.
Types
There are essentially two different types of area sensors:
- The CCD sensor and
- the CMOS sensor .