Video Editing

This is the video I made to do a bit of video and sound editing, hope you enjoy

Digital Image Processing

Digital Image Processing

Digital processing has a lot of great uses that have helped with problems caused before the invention of things like a digital camera.

Moving on to digital was very helpful as it was the end of Darkrooms in everyday pictures. A darkroom was home to a very lengthy process in developing pictures. 

Because of digital pictures now anyone can take photos and receive them with ease.

Digital images have also made it much easier to manipulate images. Instead of putting filters over the camera lens or making sure you've got exactly what you want in the picture and nothing around the edges but with digital images this can all be done with a few simple clicks. 

Harmonics

Harmonics

This post will take a look at the use of harmonics. 

A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency (http://en.wikipedia.org/wiki/Harmonic)

These screen show the addition of harmonics on a basic sine wave along with the formula to be written to add the harmonics to the wave.

This is the original sine wave

This is what the sine wave looks like when its 3rd harmonic has been added.

The sine wave with 3rd and 5th harmonics

This is what the expression looks like for a sine wave with 3rd and 5th harmonics

This is as the wave progresses into 3rd, 5th and 7th harmonics

 Expression used to add 3rd, 5th and 7th harmonics

The final wave with 3rd, 5th, 7th and now 9th harmonics

The expression with the 9th harmonic added

As you can see the wave is slowly approaching a square wave more and more with each harmonic

The Human Ear

The Human Ear

As a blog about Audio, Image and Video processing a post must be included about the human ear, the way we all hear the sounds mentioned in this blog. I will explain different parts of the ear and how they work in slight detail.

Outer ear

The outer ear is the part of the ear you can see, it is designed to funnel the sound into the ear canal that carries the sound to the middle ear. The shape of the ear is designed on purpose to get as much sound into your ear, increasing the effectiveness of human hearing.

Middle Ear

The sound after traveling down the ear canal hits the ear drum which is a very thin membrane. The ear drum is so thin that loud enough noises can burst it. The ear drum vibrating causes a small bone called the hammer, one of three small bones in the ear, to vibrate accordingly passing the vibration onto the anvil and then the stirrup. 

Inner Ear

The stirrup passes the vibration to the Choclea that is the start of the inner ear. The choclea is a liquid filled sack shaped like a shell which is full of tiny little cells attached to nerve fibers which transmits the signals through to the brain which is then interpreted as sound.

Digital Signal Processing

Digital Signal Processing

This post is about storing sound waves in a digital way.

To convert an analogue sound wave into a digital one is must pass through a digital signal processing system, this puts the sound through a filter to remove unwanted frequencies and then it is converted from analogue to digital. You can then process the signal as you wish using certain operations such as filters etc. To then listen to the sound it must be passed through a converter changing it back to analogue then another filter which brings it back to an analogue sound for the human ear.

There are some advantages and some down sides to converting an analogue signal to a digital one.

This link will take you to a page giving you a list of all the pros and cons http://www.planetoftunes.com/digiaudio/pros_cons.html

I will first explain one of the downsides to the conversion which is the sample rate.

Converting to digital is a complex process as a sound wave is a flowing curve but to get the signal in a digital way you have to choose a sample rate, which means for every time it takes a sample it will take the point it is at in the curve. after collecting all the points it will use them to make a line that resembles a curve

This means that the signal will lose detail unless you increase the sample rate but the more you increase the sample rate the larger the size of the digital file.

In this image example the top file would be much larger in size than the one at the bottom.

Yet one advantage to digital signals is they are extremely easy to alter. As the signal basically becomes a line of code meaning you can change almost everything about the file with a program such as the pitch. This would be a lot harder to do on an analogue signal.