Digital Signal Processing Reference
In-Depth Information
Fig. 2
Photo processing
pipeline
a
Capture
Develop
Print
Film camera
b
Print
Post-processing
Store
Organize
Capture
Digital Display
Digital camera
stored either in raw pixels or as compressed images. Inside the camera, the following
image processing algorithms are usually involved:
2.1.1
Focus and Exposure Control
Based on the content of the scene, camera controls determine the aperture size, the
shutter speed, the automatic gain control, and the focal position of the lens.
2.1.2
Pre-Processing of CCD Data
In this step, the camera processor removes noise and other artifacts to produce an
accurate representation of the captured scene.
2.1.3
White Balance
The goal of this step is to remove unwanted color casts from the image and colors
that are perceived as “white” by the human visual system are rendered as white
colors in the photo as well.
2.1.4
Demosaicing
Most digital cameras have a single sensor, which is overlaid with a color filter array
(CFA). For example, a CFA with a Bayer pattern alternates red and green filters for
