29-06-2012, 01:57 PM
Image Sampling and Quantization
[attachment=26107]
Uniform Sampling and Quantization:
To create a digital image, we need to convert the continuous sensed data into digital form, which involves two processes: sampling and quantization.
Analog images are represented by waves of photons traveling through space.
An image may be continuous with respect to the x and y coordinates and also in amplitude.
What is Digital Image?
When x, y and the amplitude values of f are finite, discrete quantities, the image is called digital image
A digital image is composed of a finite number of elements, each of which has a particular location and value. These elements are referred to as picture elements, image elements and pixels.
Spatial and Gray – Level Resolution:
Sampling is the principal factor determining the spatial resolution of an image.
It is the smallest detectable detail in an image.
Resolution is the smallest number of discernible line pairs per unit distance.
Gray level resolution is the smallest discernible change in gray level, which is a subjective process.
Aliasing and Moiré Patterns:
The principal approach for reducing the aliasing effects on an image is to reduce its high – frequency components by blurring the image prior to sampling.
The effect of aliasing can be seen Moiré pattern.
[attachment=26107]
Uniform Sampling and Quantization:
To create a digital image, we need to convert the continuous sensed data into digital form, which involves two processes: sampling and quantization.
Analog images are represented by waves of photons traveling through space.
An image may be continuous with respect to the x and y coordinates and also in amplitude.
What is Digital Image?
When x, y and the amplitude values of f are finite, discrete quantities, the image is called digital image
A digital image is composed of a finite number of elements, each of which has a particular location and value. These elements are referred to as picture elements, image elements and pixels.
Spatial and Gray – Level Resolution:
Sampling is the principal factor determining the spatial resolution of an image.
It is the smallest detectable detail in an image.
Resolution is the smallest number of discernible line pairs per unit distance.
Gray level resolution is the smallest discernible change in gray level, which is a subjective process.
Aliasing and Moiré Patterns:
The principal approach for reducing the aliasing effects on an image is to reduce its high – frequency components by blurring the image prior to sampling.
The effect of aliasing can be seen Moiré pattern.