Difference between the Analog signals and Digital signals
Conversion of Analog signals to Digital signals
Most of the image sensors are in the analog signal, and digital processing cannot be applied on it, as it requires infinite memory to store because signals have an infinite value that is why we cannot store it.
To create a digital image we can convert data into digital form.
For the conversion there are two steps:
To convert an analog signal into a digital signal, both its axis(x,y) are converted into digital format.
As we can see that image is continuous in its coordinates(x-y). So sampling deals with digitizing of co-ordinates and quantization deals with digitizing the amplitude.
In analog signals, there are continuous electrical signals that vary with time. With the help of subsystem, a sampler extracts continuous signals for the sampling of signals.
(Sampling of signals)
Sampling is done along the x-axis of signals that continuously differs with time. It is divided into two category one is sampling and other is downsampling.
In downsampling, the range of values on the x-axis is always less.
It is a process of image processing, in which continuous and time-varying values of analog signals are divided into non-overlapping discrete and unique values assigned to each subrange.
Sampling and quantization are opposite to each other. Sampling is done along the x-axis but quantization is done along the y-axis.
In the image processing, the sampled image is considered as a digital value. When there is a transition of states between time-varying values of image function and its digital equivalent signifies quantization.
(conversion of analog signals to digital signals).
The main problem in the image is the continuous occurrence of false contours which can be quantized later with inadequate brightness levels. The fine shading of the image depends on the level of quantization.