Week 9- image processing

An image capture system contains a lens and a detector. In digital photography the detector is often a charge coupled device (CCD), a linear or matrix array of photosensitive electronic elements.

Pixelization can be seen with the unaided eye, if the sensor array is too low. Increasing the number of cells in the sensor array, increases the resolution of the image captured.

Before the light is collected by the lens is focuses on to the sensor array, it is passed through an optical low pass filter that serves to

Compensate for false colouration

Exclude any picture data, which is beyond the sensor's resolution.
Reduce infrared and other non-visible light.

Four common categorisation of DIP operations are analysis, manipulation, enhancement and transformation.

Four common categorisation of DIP operations are analysis, manipulation, enhancement and transformation.

A pixel is the smallest digital element manipulated by image processing software.

Each pixel is individually coloured but since they are of finite size, pixel only approximate the actual colouring of a subject. Thus bit maps often show blocky areas or jagged lines under close examination.

Analysis operations provide information on photometric features of an image e.g. colour count, histogram

Manipulation operations change the content of an image e.g. flood fill, crop

Enhancement operation attempt to improve the quality of an image in some sense e.g. heighten contrast, edge enhancement

Transformation operations alter the image geometry e.g. rotate, skew

week 8- Lab

I used Photoshop 7 to apply custom filters to this image

What is the effect of the default mask?

the effect ranges depending on the numbers you type in.

the higher the number you type in you'll get a higher contrast. 

The lower, the lower.

if you type in anything less than 0, you get complete blackness.

Suggest possible of this filter technique for processing digital photographs?

This technique could be used for flyers or posters to make them more unique, obscure look in order to stand out.

 Create a new filter that is all zeros except for the centre value which should be 1. What does this filter do and why?

This filter brings it back to normal. The filter does this because 0 is the original image.

Week 7- light

Light which is generated enables us to see.

The most common sources of this light would be the sun or a light bulb

Light can reflect off of surfaces and can travel through most mediums. An example of this is the glass of a lightbulb or water in a swimming pool.

When light travels through different mediums it ‘bends’ creating a change in the way we view light.

Light bounces off of mediums, for example, a mirror. This allows objects such as the sun to reflect into our houses and allow light to travel virtually everywhere.

The speed of light is around 300,000,000 m/s

This is the fastest thing in the known universe.

Light is Electromagnetic Radiation

There are two aspects to colour- Pigment and Wavelength

Pigment is an aspect of the object we're talking about when we ask "what color is it?"

Wavelength is an aspect of light, which is made up of different wavelengths.

White light contains all the possible wavelengths.

Black light contains none.

When light hits pigment, some of these wavelengths are absorbed and some are reflected.
A black pigment absorbs all the wavelengths

When something looks blue, it is because wavelengths in the blue spectrum of light are being reflected.

Things look different in different lights because not all light is white light. Something will look different under a light bulb than under sunlight.

Week 6- audio signal processing

Applying the compression effect to the SopranAscendDescend.wav caused a reduce in dynamic range, producing consistent volume levels and increasing the loudness of the file.

Compression is effective for voice-overs, because it helps the speaker or singer stand out over an instrumental soundtrack and background audio tracks.

Standard settings

Amount
Controls the amount of compression.

Advanced settings

Ratio
Sets a compression ratio between 1‑to‑1 and 30‑to‑1. For example, a setting of 3 outputs 1 dB for every 3-dB increase above the threshold. Typical settings range from 2 to 5; higher settings produce the extremely compressed sound often heard in pop music.

Threshold
Sets the input level at which the compression begins. The best setting depends on the content of the audio and style. To compress the extreme peaks and retain a lot of dynamic range, use thresholds around 5 dB below the peak input. To highly compress audio and greatly reduce dynamic range, try settings around 15 dB below the peak input level.

Attack
Determines how quickly compression starts after the audio output goes further than the threshold. The default of 10 ms works well for a wide range of source material.

Output Gain
Boosts or cuts amplitude after the compression has been applied. Possible values range from ‑30 dB to 30 dB, where 0 is unity gain.

Release
this determines how quickly the compression stops when audio drops below the threshold. The default, 100 ms, works for a wide range of audio.

Ambient Sound and Reverb:

The 'reverb' you hear on records is usually the result of ambient micing techniques, rather than artificial reverb. Opening the doors of a studio and placing ambient mics in hallways etc.