Computer graphics: Image processing

One image is worth more than ten thousands words.

Image processing mainly focus on digital image processing.

With the improvement of people's life, digital image processing is walking into common people's world. Photoshop is a famous tool to process pictures. In this article, I will talk about what digital image processing is, history of digital image processing, and key stages in digital image processing.

1. What is image processing? Image processing technology mainly includes image digitization, image encoding, image enhancement, image restoration, image segmentation, and image analysis. It focus on two tasks: (1)improvement of pictorial information for human interpretation. (2) processing of image data for storage, transmission and representation for autonomous machine perception.



2.  History of digital image processing. One of the first application of digital imaging was in the news paper industry at early 1920s. Many of the techniques of digital image processing as it often was called, were developed in the 1960s. The cost of processing at that time was fairly high. With the development of computing equipment, that situation was changed in the 1970s.  Digital image processing has become the most common form of image processing in the 2000s.

3. The process of digital image processing includes image acquisition, image enhancement, image restoration, morphological processing, segmentation, object recognition, representation and description.

In the three paragraphs above,  I simply show you  definition, history, and key stages of digital imaging. If you want to know more about it, you can search: image processing by Google. You will find tons of materials. Today, imaging processing is a really hot topic.

reference:wiki

Scientific Computing: Numerical analysis

Pythagoras was a great Greek philosopher.  His motto was “All is number,” which means that all things in the universe obey the rules of numbers. This shows how important numbers are in our life.
So analyzing the numbers are becoming necessary. Numerical analysis mainly focus on this.

Numerical analysis is the subject which uses computers to solve mathematical problems. It is one branch of Mathematics.

In fact, Numerical Analysis is a required course in some departments like Mathematics, Physics, and Chemistry.  By smart Google, you can get tons of materials about Numerical analysis. In this post, I will mainly show you what I learned about it in university.

Firstly,   the mainly research contents of Numerical analysis are Curvefitting, Interpolation, Approximation of Function,  Solving equations and systems of equations, Solving Differential equations,  and Solving singular value problems. I still remember my first class. When the instructor showed us its' strong ability by PPT(PowerPoint), I was shocked. I thought I finally got the magic wand to solve annoying differential equations.



Second, from the paragraph above, we can find Numerical analysis is like a generalist who can solve many complicated problems. However, maybe you will be disappointed when you know that it only gives people the approximate solution. In fact, I had the same feeling like you when I got it from my instructor. But with more and more knowledge, I find approximation is reality and exactness is dream in actual application. Approximated solution is enough for our actual problems.



Finally,  in general, computers solve actual problems by 5 steps: presenting actual problems, creating mathematical model, numerical analysis, designing program, and implementing program. Every step is not easy. Especially, the step of analyzing the numerical is harder. Scientists need try their best to use all kinds of tools to give better approach of the "exact" solution.

reference:wiki

Scientific Computing: Computational science

Are you familiar with Computational science? I didn't really know about it one week ago. So far, I have to admit that I am still a layman. In this post, I will show you what I learned about it recently from definition, application, and process.

Firstly, what is Computational science? Computational science(also scientific computing, scientific computation) is a rapidly growing multi- and interdisciplinary field that uses advanced computing and data analysis to understand and solve complex problems. It uses mathematics and computers to explore "real world" problems in science.

Second, where do we apply Computational science? Problem domains for computational science/scientific computing include: Numerical simulations, Model fitting and data analysis, and Computational  optimization. 
Computational Science complements, but does not completely replace, field experimentation in scientific  research.
It is ideally suited to exploration of problems which are too expensive, too dangerous, too difficult to control...for experimentation in the field. For example, we can use it to reconstruct  and understand known events such as earthquake, tsunamis, and other natural disasters.

Finally, Computational Science Process.  When we use Computational science to solve problems, we firstly construct working model. And then we need to build mathematical behavioral model with the help of working model. The next step is to create computational model. Finally, we can get results/conclusion according to the analysis from computational model. The image below shows the whole process.

In sum, Computational science is an important tool in modern scientific research. Especially, we can use it to imitate special scenarios like earthquake and sub-atomic particle behavior. The cost will be huge to reconstruct these scenes without it.

Computational science is an useful and interesting field. Let's learn and discuss it together.

reference: Journal of Computational Science, Wiki

Communication and Security: Hardware Security

When we talk about communication, the security has been a topic for a long while and it will keep being a top for ever.  The security issue can be classified to software security and hardware security. For example, the computer virus is normally a bad software which can harm the computer and the communication. Here let's talk about the hardware issue.


Computer hardware include CPU (central processing unit), main memory chip, main board, hard drive disk (HDD), monitor, keyboard and others. CPU is one of the most active components which conducts many kinds of operations, and it itself may pose many threats on security. Since CPU is usually manufactured by a few companies, and operates their only instruction set in a way that is not so public. They have enough reasons to keep it operating in this kind of secret way, for example, that is simply the business secrete.

  However, from another viewpoint, since it's operating secretly, there are few people that really know how it operates, and maybe even fewer people know what its normal working status is, and whether it's operating in a normal way or operating in a harmful way. Maybe the CPU is almost always, say, 99% of time, normally, but its operating in another 1% of time may do any kind of harm, including releasing sensitive information that is usually not permitted, implanting virus codes / instructions, cleaning important data, and so on so forth.

Theoretically until we know all the secrete behind the CPU, we can imagine that whatever kinds of security threats can be introduced by the CPU itself, not to mention that there are so many other chip sets inside our computers.