22/02/25Monochrome cameras capture only the intensity of light in greyscale, while color cameras can capture color images, in the form of Red, Green and Blue (RGB) information at each pixel. While gaining additional color information can be valuable, monochrome cameras are more sensitive, with advantages in fine detail resolution.
Mono cameras measure the amount of light that hits each pixel, with no information recorded about the wavelength of the captured photons. To create a color camera, a grid consisting of red, green and blue filters is placed over a monochrome sensor, called a Bayer grid. This means that each pixel then detects only red, green or blue light. To form a color image, these RGB intensity values are combined – this is the same method computer monitors use to display colors.
The Bayer grid is a repeating pattern of red, green and blue filters, with two green pixels for every red or blue pixel. This is due to green wavelengths being the strongest for most light sources, including the sun.
Color or Mono?
For applications where sensitivity is important, monochrome cameras offer advantages. The filters required for color imaging mean that photons are lost – for example, pixels that capture red light are unable to capture green photons that land on them. For monochrome cameras, all photons are detected. This offers a sensitivity increase of between 2x and 4x over color cameras, depending on the wavelength of the photon. Additionally, fine details can be harder to resolve with color cameras, as only ¼ of pixels can capture Red or Blue light, the effective resolution of the camera is reduced by a factor of 4. Green light is captured by ½ of pixels, so sensitivity and resolution are reduced by a factor of 2.
Color cameras however are capable of producing color images much more quickly, simply and efficiently than monochrome cameras, which require additional hardware and multiple images to be acquired to produce a color image.
Do you need a color camera?
If low light imaging is important in your imaging application, then a monochrome camera may be the best choice. If color information is more important than sensitivity, a color camera may be recommended.
