Single CCD vs. 3 CCD Cameras
Using color cameras with Bayer filter mosaics for machine vision applications can present limitations. In a monochrome camera, one photo sensor on a CCD represents one pixel of information in the output image. A color camera with a singular CCD uses the same principle, but the camera takes data from the filtered photo sensors and uses interpolation to fill in the missing data for the red, blue and green color planes. This leads to a lower resolution image on each of the three color planes.
These limitations led to the development of the 3CCD color camera, with its high-color precision that provides distinct advantages over Bayer solutions. In a 3CCD RGB color camera, each CCD is independently filtered for each value of red, green and blue. The three CCDs use one or multiple prisms, to direct the light towards each CCD. A prism assembly splits the incoming white light into red, green and blue light.
The advantage of having three independently filtered CCDs is that there is no reduction of image quality on the output image. A camera with three independent CCDs no longer has to use a filter mosaic to create color. Instead it combines the values from the each one of the filtered CCDs to create a very accurate pixel color on all three color planes.
The main reason for choosing a 3CCD camera is:
- To update an existing monochrome inspection to a color inspection.
- A Bayer-filter camera is less light sensitive because of the color filters, which absorb light.
- Higher Color Fidelity -With the 3CCD, the image light goes through a prism and is then split into three spectral bands, with very little loss of light intensity and higher color fidelity.