Sampling and quantization sampling and quantization
In order to become suitable for digital processing in order to facilitate digital processing
an image function f (x, y) must be digitized both spatially and in amplitude. function of the image must be digitized in space and the amplitude
Typically usual
a frame grabber frame grabber
frame grabber grab grabber grab frame
digitizer digitizer
Hence in order to create an image which is digital so in order to create a digital image
we need to covert continuous data into digital form we will need continuous data to a digital form
There are two steps in which it is done: he divided into two steps: acquisition and quantification
The sampling rate determines the spatial resolution of the digitized image, while the quantization level determines the number of grey levels in the digitized image. Sampling rate determines the spatial resolution digitized image, the quantization level is determined gradation number of the digitized image.
sampling rate sampling rate, the spatial resolution the spatial resolution of the spatial: of or relating to space.
A magnitude of the sampled image is expressed as a digital value in image processing.
Size A magnitude of the sampled image acquiring images
is expressed as a digital value in image processing performance of digital values in the digital image
digit n.
digital adj.
digitizer n. digitizer
The transition between continuous values of the image function and its digital equivalent is called quantization. Transitions between successive values of their digital equivalent function of the image is called quantization.
Excessive transition transition
equivalent equivalent
The number of quantization levels should be high enough for human perception of fine shading details in the image. Number of quantization levels should be high enough to make people understand the fine shadow detail in the image
fine fine, fine, fine, fine, fine, fine
The occurrence of false contours is the main problem in image which has been quantized with insufficient brightness levels. In the absence of sufficient brightness of the quantization results in a false profile, has become a major problem in image processing
occurrence n. occur occur v. occur
false false, false, false
contours nv profile
insufficient inadequate enough, greedy yg: not enough; inadequate adequate enough.
brightness brightness
In this lecture we will talk about two key stages in digital image processing. In this lesson, we will discuss two key stages of image processing
Complete definition of Sampling and quantization will be defined properly. Collected and quantified
properly:correctly or satisfactorily.thoroughly; completely.
Spatial and grey-level resolutions will be introduced and examples will be provided. Introduce spatial resolution and gray scale, example
resolution: Resolution
a firm decision to do or not to do something.the action of solving a problem, dispute, or contentious matter.the process of reducing or separating something into its components.the smallest interval measurable by a scientific (especially optical) instrument; the resolving power.
An introduction on implementing the shown examples in MATLAB will be also given in this lecture. This lecture also describes how came here with a matlab example
implement 实现put (a decision, plan, agreement, etc.) into effect.a tool, utensil, or other piece of equipment, especially as used for a particular purpose.
Sampling: related to coordinates values sampled, and the coordinate values related to
(Nyquist frequency)
Quantization: related to values relating to quantify the intensity values of intensity
imread () - reading an image with different postfixes read image have different suffixes, reads an image having a different suffix
imresize () - resizing an image to any given size changed to change the image size of any size
figure - opening a new graphical window FIG - opens a new image window
figure: Figure, figures
:. A number, especially one that forms part of official statistics or relates to the financial performance of a company figures, in particular, constitute a part of official statistics or figures relating to its financial condition.
:a person's bodily shape, especially that of a woman and when considered to be attractive.
:represent (something) in a diagram or picture.
subplot(#of row, # of col, location) – showing different plots/images in one graphical window
Sub-picture (the number of rows, columns, position) - show different views / image in a graphics window
imshow () - displaying an image to display an image