The argument over whether to use CCD or CMOS has led some industries to suggest one is greater than the other. The truth about them is that they both have very unique strengths and weaknesses. This results in advantages when dealing with different applications. Both do the same thing. Both are imagers that convert light into an electric charge. It then takes this electric charge and processes it into electronic signals. These signals can then be used by the computer.

What is CCD?

CCD is a charge coupled device. This devices takes the charge from every pixel and transfers it through a limited number of output nodes. Often times, this number of output is no greater than one. By going through this output node, the charge can be converted to voltage. It is then buffered and sent as an analog signal off the chip. This results in the pixel being able to focus entirely on the capture of light. Therefore, the out's uniformity is impeccably high.

CCD vs CMOS

What is CMOS?

CMOS, on the other hand, is a complementary metal oxide semiconductor. A CMOS allows for each pixel to have its own charge-to-voltage conversion. Not only does the CMOS chip possess this, but they also tend to have amplifiers, noise correction and digitization circuits. The output for a CMOS, therefore, are digital bits. However, because each pixel does its own conversion, the uniformity is low.

Is CCD Better or Worse than CMOS?

Neither is better than the other. CCD has traditionally provides a much higher quality image. Therefore, it is used a lot in photographic, scientific and industrial applications. However, while the CCDs can provide incredible image quality, the downfall to it is that the system size of jeopardized. Typically, a CCD is much larger than a CMOS. However, in the above mentioned applications, size isn't so important and therefore, they can deal with the loss in system size in exchange for image quality.

CMOS, on the other hand, allows for more functions on the chip, less power needed to run it and smaller system sizes. However, they have their downfalls. While the system size is smaller, the image quality decreases and at some instances, the cost goes up. This is primarily because developers are trying to put more on the same chip which requires more precise manufacturing.

To prove, though, that neither is superior to the other, is the use of CCD and CMOS in opposite applications. For example, one can easily find a CCD in a low-cost low power cellphone camera. On the flip side, one can find a CMOS sensor in high-performance industrial cameras. The end result is that neither is superior to the other. Both are beneficial and, in the end, all depends on preference and needs.