Video Links

https://www.youtube.com/watch?v=I7KmAYJhpQM

https://www.youtube.com/watch?v=IoHFluyUFMY

Week 9: Audio/Video Lab 2 - 5 Minute Film

Week 9: Audio/Video Lab 2 - 5 Minute Film

Week 9: Light Lecture 2

Week 9: Light Lecture 2

Light - Light, is a form of energy that is detected by the human eye. In certain conditions light appears to act like a stream of particles. In other conditions, like a wave. A way in which light differs from sound is that it does not require a medium to propagate. Light can travel from the sun, through a vacuum (outer space) and reach the Earth.

Waves - Light is a transverse wave, much the same as a ripple you would see on the surface of water. The vibrations of light waves are at right angles, up and down/side to side, to the direction of motion from the origin of the disturbance.

Light Waves - Light waves, are electromagnetic waves. This means that they are a particular form of Radio Wave and in terms of this our eyes form a Radio Receiver. The range of light that is visible to the human eye is only a small part of the electromagnetic spectrum, covering frequencies from around 400THz to 750THz. (THz = Tera-Hertz = 10 to the power of 12Hz). This range appears to us as different colours. Red at low frequencies and Violet at high. White being a mixture of many different frequency components or colours.

The Electromagnetic Spectrum - http://mynasadata.larc.nasa.gov/science-processes/electromagnetic-diagram/

Velocity of Light - In a vacuum we know that light travels at a constant speed of 300,000 km/second. So 300 multiplied by 10 to the power of 6 m/s. In air this is a little less, slowed to around 2/3rd of this. The change in velocity at air/glass interference makes glass a very useful medium for lenses. From this we know that in air, light travels at around 1,000,000 times the speed of sound. So, to travel the 3 metre length of an average living room light would take:

Frequency and Wavelength - We know that the frequency of a wave is the number of complete cycles per second. The frequency of a light wave is independent of the medium that the wave is travelling through or via. The speed at which this wave travels or it's velocity is equal to it's wavelength multiplied by it's frequency. So:

This means that a 500THz Light-Wave has a wavelength in air, 300*106 over 500*1012 m/s. So the wavelength is 600nm and appears Orange. The same light wave in glass would have wavelength of around 400nm. Note that it still appears Orange being that the frequency of the wave is independent of the medium it is travelling in. 

Components of "White" Light - White light, the light from the sun is a mixture of all of the colours in the visible spectrum, with some being a little more powerful than others, dependent on the source of course. http://www.precisioninfo.com/index.php?doc_id=62

Week 8: Video Lab 2

Week 8: Video Lab 2

A short film is to be used to promote the Gallery of Modern Art in Glasgow (GOMA). A TV company can only show 1 minute of footage. The original footage obtained (in the supplied file) is unfortunately too long and must be edited to be only 60s in length. Using Moviemaker or another video editor of your choice, perform edits to show a smooth walk-through of the gallery.

Your final film should demonstrate insightful editing of video and many replace some or all of the audio track with a new track. The new audio track should be composed of carefully chosen and edited from sounds from freesound.org. The audio track should match the mood of the video edits that are performed on the original footage.

There is no especially wrong way to perform this task. The task is an opportunity to integrate audio and video editing skills together. The task will run for the remaining lab session.

Upload you final video to YouTube creating an account as necessary.

Answer the following
- Please write a few paragraphs explaining why you made the edit cuts in the footage that you did?
- What emotional effect did you intend to create by making each edit?
- What features of the Video editor and audio editor did you find particularly challenging to use?
- If you were to perform this task again what would you do differently and why?

Firstly I'll talk about what cuts I made. Initially I started with removing the intro title card as I planned to replace it with my own at the end. Next I thought it would be a good move to try and cut out most of the parts where the camera was transitioning from piece to piece. I replaced these cut parts with fade ins between each piece of art to create the idea of having moved between them. One or two points of interest in the video weren't actually all that important for getting an idea about the museum and as such were cut to bring down the time and allow focus on the other pieces.

I tried to make the video into a calming view of the different pieces. I focused exclusively on any scene that involved a detailed look at the pieces of art. I found that the parts of the video where the camera was moving through the museum were actually somewhat boring and distracted a lot from what could be seen. For the music I used I implemented two tracks to play through the full length of the video. One was ambient museum noise with it's volume reduced so as to not over power the music I added afterwards. This ambient noise was purely for immersion. The music I used was a slow, electronic number that remained at a constant pace with some calming tones. Something I thought was very fitting for the museum.

In case this turned out to be too little to keep someones interest I used a track of a bottle smashing for the adjacent clip. This unedited track would loudly play not once, but twice. I used this to try and snap attention back to the video. At the end as the title card appears I use a small laugh track to convey the humor of the statue that stands out the front of the building.

The only parts I found any difficulty in was trying to keep the clip to the length allocated and fitting the two bottle smashes in perfectly with the video. I managed to work out how to correctly use the trim tool in the video editor and made use of the ability to generate silences to match up the bottle smashes with the video. If I had to do this again I might record my own background music, or even some dialogue to explain the pieces you can see. Possibly turning the video into a small documentary.
A LINK TO THE VIDEO
https://www.youtube.com/watch?v=IoHFluyUFMY&feature=youtu.be

Week 8: Looking at Light

Week 8: Looking at Light

Looking at Light: The light that is created and generated by various objects in our surroundings allows us to see, record and capture images of the world. In terms of manipulation and display of images, our knowledge of light and how we use it affects the quality and expressive power of the images that we create or capture.

Vidi: We can distinguish differences between very similar concepts such as looking, seeing and observing. Looking is the idea of arranging or finding what we can/want to see. Seeing itself is the act of receiving light energy and converting it into nerve impulses. Observing is the idea that we then analyse or interpret the nerve impulses in terms of various objects. For example mirrors or effects such as a mirage. From a young age we begin to grow content with the world and slowly stop putting an emphasis on the observation stage until we notice an important change. Artists, photographers and the like learn to observe and by doing so become more aware of their surroundings.

The Ayres Rock: As the brightness of the sunlight that hits the rock changes throughout the day, so to does the colour and due to this it changes the appearance and the general mood set by an image that captures this scene. 

Sources: https://emmakellydooz.wordpress.com/tag/ayers-rock/

http://www.kpopstarz.com/articles/110340/20140911/beautiful-sunset-in-ayers-rock-australia.htm

http://www.davidreneke.com/astro-events/

In the Cold Light of Day: The position of the sun at different points of the day is the factor than has the greatest effect on natural lighting and as such has the ability to change the appearance of any object.

Who Loves the Sun? As the run rises and sets you will see light changes in a variety of ways including a pronounced shift in colour. Both early and late in the day the suns position is low and as such objects will be casting long shadows. Around mid-day the sunlight is sometimes called "white" light as it is seemingly colourless and contains the most even mix of each and every colour in the spectrum. At this point objects will cast short shadows against the sunlight. Below you will see examples of the sun at different heights.

Pre Dawn: http://eecue.com/p/30294/Pre-dawn-Above-Palm-Springs.html

Pre-Dawn features a yellow/orange sky.

Morning: http://bo0xvn.deviantart.com/art/Morning-sun-178239743

The morning has the yellow/orange sky turning blue.

Mid-Day: http://inanutshell.ca/lifestyle/midday-musings-2/

During mid-day you see the idea of "white"light.

Twilight: http://poetrypoem.com/cgi-bin/index.pl?sitename=poetessktj&displaypoem=t&item=poetry&poemnumber=1044029

During Twlight you will see much deeper tones and a heavy contrast.

Cloudy Mid-Day: On cloudy days, light will often appear as white but in reality the light from the sun actually has a bluish tint in this scenario. Clouds actually act to soften and diffuse light which leads to a much more even spread.

Source: From Lectures

Diffuse/Shaded Light: Diffuse or shaded light is often used for portraits as it reduces brightness whilst illuminating the subject much more evenly.

The Play of Light: The much more obvious and dramatic displays of the change in quality of light appear during the sunrise and sunset. This "play" of light is the result of the changing nature of three basic ideas. Direction, colour and contrast.

Light Play on the Grand Canyon:

Source: http://fineartamerica.com/featured/morning-light-shadow-play-grand-canyon-national-park-shawn-obrien.html

Direction: The direction in which light will strike an object/subject is very important. Subjects may be illuminated by a number of things such as side-lighting, front-lighting or back-lighting.

Front, Side and Back Lighting: Front lighting is the name for when the source of light is behind the person observing an object or scene. Using this allows the light to cover the subject evenly and by doing so reveals a lot of detail about the subject. Side lighting is used to create long shadows which in turn are used to emphasize the texture of an image, which in turn gives a greater sense of shape, dimension and depth. In order to get the most dramatic effect you can use back-lighting. In back-lighting the source is originating from behind the subject. This creates silhouettes and a number of other effects.

Front-Lighting: Here is an example of front-lighting from the lecture. Observe the rich saturated colours visible on a clear sunny day.

Front-Lighting vs Side-Lighting: Due to front-lighting being much more even it has what you would call a flattening effect. Side-lighting however creates long shadows and as such gives a greater sense of shape, dimension and depth. Side-Lighting is also used to bring out texture. Both images from the lecture.

Back-Lighting: Below is an image from the lecture. The image is a due of fishing boats resting on the water. With the use of back-light skimming off of the surface there is an effect that seemingly creates many tiny points of light that give the water an almost shimmering appearance.

When back-light is passed through a translucent object/subject there is the effect of a glow of colour from the object. This can create the stained glass window effect.

Contrast: A high contrast light is an intense and directional light that casts shadows with very hard edges. On a normal sunny day the sun gives off "hard" or high contrast lighting. The brightness of this light produces very sharp details and rich saturated colours as well as the creation of strong imposing shadows. More softer, low-contrast light appears on an overcast day. When clouds scatter the light from the sun it's more evenly spread and less bright. In low-contrast light, you can see clear differences between tones blending casually. This in turn creates a delicate mood.

High and Low Contrast: 

Source: http://www.atpm.com/9.07/design.shtml

Contrast vs Detail:

In a high contrast image (top), contrast reduction will fill in shadows and as such reveal hidden details. Image from lectures.

Colour Film: The human eye will attempt to adapt to shifts in colour. The eyes will re-calibrate automatically so as to make the perceived shifts approach white balance. Film is much more sensitive than the eye to shifts in the colour of light. Film's response to this is having colour fixed at manufacture. Due to this daylight film produces pictures with a orange tint which lies underneath tungsten light sources and a greenish tint underneath fluorescent light. The shifts in colour can be dealt with by way of image processing.

The Colour of Light:

Below is an example of daylight film in response to different lighting conditions. The image is from the lecture.

Colour: The human eye is naturally attracted to colour. More so to bright or light colours. Colour as such has a powerful impact on the mood of an image or scene. Subconsciously composers or artists think about colour and use the human appeal to the masses.

Yellow as a colour can add/create a bright tone. A happy and cheerful feeling. Red is often used to make things more exciting and is a warm colour. Greens and browns are what most people refer to as restful colours and are associated with nature and earth. Moody blue is a more calm, and cool feeling whilst a not so moody blue would create a more colourful contrasting backdrop to draw attention to subjects in the image. 

The Colourise Effects:

Observation: You can make your images a lot more expressive in a number of ways. One way to do this is to exercise control of lighting. Below you will see a picture of a small palm tree. Notice the pattern and shadow on the palm.

Selection: The pattern visible in the front-lit palm is selected by zooming in (see below). The shadow from the right hand side of the palm has been used to soften the cropping of the image.

Modification: Flipping about the vertical axis and re-colouring with a more saturated green/yellow makes the palm look back-lit. It is as if we are viewing it from the other side.

Week 7: Image Lab 1

Manipulating images using arithmetic 

Image filtering, enhancement and general manipulation using Photoshop

1) Find the images on Moodle to be used in this lab and download on to your desktop.

2) Click on All Programs->AdobeCreativeSuite4ProductionPremium and run Adobe PhotoshopCS4

3) Use File\Open CH_Tor.jpg to display the image in Photoshop.

4) Perform Image->Image Rotation->90 degrees CW

5) Apply a custom filter to the image in the manner discussed in the lecture to filter the image as Filter->Other->Custom
Modify the default Mask to
    -1

-1  4 -1

    -1
What is the effect of the default mask? Why do you suppose that it creates the effect that you see?

The default mask seems to change the image to a black and white style. In doing so it highlights straight edges with white whilst solid blocks of colour seem to change into black. I'm not entirely sure why this is the output. I assume that the value of the pixels found in the straight lines is turned into a negative whilst the reverse is the case for large spaces of the same colour.

6) Experiment with various masks and explore the use of the preset masks in the High pass, maximum and minimum options. Where possible describe and explain what you see?

On the left is the Maximum Mask, the middle is the High Pass Mask and the right is the Minimum Pass Mask. The Maximum mask seems to be darkening/amplifying the darker colours in the tower. Whilst the lighter colours seemingly remain untouched. The Minimum mask does the opposite and lightens the lighter colours in the tower. For both filters the is most notable in the actual clock. The High Pass Mask is a little harder to explain. A glow is created around the main points of the image and everything seems to become a little foggy. The gradient blue in the back ground is now for the most part a solid grey. 

7) Suggest possible uses of this filter technique for processing digital photographs?

The most plausible use for any filter technique in terms of processing digital photographs would be to first and foremost improve the quality. Decrease pixilation, smooth edges that need smoothed and sharpen lines that need sharpened. Following touch ups another use would be to use the filters for additions and extras. Something to change the image for the better to make it stand out a little from the original.

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

How can you check that it operates as you think it does?

The mask seemingly doesn't change anything. The only way to check that this mask is operating as I think it has is to simply view both the original image and the image with the mask beside each other and by doing so I see no differences in the image.

9) Create a new filter with a two by two matrix of 1’s near it’s centre. What does this filter do and why?

This filter seems to dramatically brighten the colours. Although you can still see some examples of the darker textures. The sky being one of lighter colours in the image is now almost completely white. This is the effect of saturation.

10) Create a new filter with a two by two matrix with +1’s on one diagonal and –1’s on the other. What does this filter do and why?

This filter seems to be a much more extreme version of the find edge filter from before. As you can see the edges are now highlighted as white, very faintly against an incredibly dark shade for the rest of the image. Once again this is reversing the value of the pixels to accomplish this.

11) Some other filters and their effects:

On the right is the tower with an embossed style of filter applied to it. It seems to highlight the various shapes shown in the picture, notably the individual bricks in the building. The image on the left has been heavily sharpened and accomplishes a similar style of the embossed image.

Week 7: Digital Image Processing

Week 7: Digital Image Processing

Why use Digital Image Processing:

• It removes the cons of using a darkroom and the time required alongside the chemicals involved.
• It allows for a flexible environment in which you can experiment as much as you want without consequence.
• There is a large amount of pre-defined options and operations available as opposes to a traditional darkroom. The amount of these operations and options continues to grow.

Digital Camera Imaging Systems: 

A camera contains both a lens and a detector. In digital photography the detector is more often than not a CCD or charge coupled device. This is a linear or matrix array of photosensitive electronic elements. 

A 35mm film frame measures 36x24 mm. A typical CCD array is only 6x4. The lens of a digital camera must then be a high quality to condense the optical image onto an area 36 times smaller.

Digital Camera Image Capture: 

On an area array sensor, a grid of many thousands of tiny photocells each less than 5 micro metres square creates pixels by sensing the light intensity of small bits of the image formed by a lens system. 

Sensor Spatial Resolution:

Pixelization can be seen with the human eye if the resolution is too low. Increasing the number of cells in the sensor array will in turn increase the resolution of the captured image. Sensor devices have around 1 million cells.

Digital Camera Colour: 

In order to capture image in colour, red, green and blue filters are placed over the photocells. Each cell is then assigned three 8-bit numbers (2 to the power of 8 is equal to 256 levels) that corresponds to the brightness values of red, green and blue. For example orange has a red brightness of 227 red, 166 green and 97 blue.

Digital Camera Optics: 

Before light collected by a lens is focused on to the sensor array, it is passed down through an optical low-pass filter that:

• Gets rid of any picture data beyond the sensor's resolution.
• Compensates for false coloration and RGB moire caused by large changes of colour contrast in terms of pictures of thin stripes and fine point sources.
• Lowers the infrared and other non-visible light, both of which that disturbs the sensor's imaging process.

What is Moire and how do you prevent or remove it?

Source: http://static.photo.net/attachments/bboard/00a/00aJtp-461139584.jpg

Moire is a pattern of wavy lines that every now and again appears on objects in digital captures. This occurs when fibers or fine details in an object match the pattern of the imaging chip in the camera. Some cameras uses anti-aliasing filters to blur these areas on captures but others don't use these because it sacrifices image sharpness. With or without this filtering every camera can creating moire.

Digital Image Fundamentals: 

Digital images are known as bit-maps or raster-scans. These are compsed of an array of pixels. Each pixel in the image is a uniform patch of colour, but on the screen is made up of red, green and blue phosphor dots or stripes.

The Pixel:

A pixel is the smallest digital image element that is manipulated by any image processing software. Each pixel is individually coloured but due to their size they can only approximate the actual colouring of an object, Due to this bit maps will show blocky areas when zoomed in. 

Bit-Mapped Graphics:

A bit-mapped image is represented in memory as an array of bits. Each array codes the colour of a single pixel. For example 8 bits for red, green and blue levels needs a group of 24 bits. The array of pixels could be 640x480(VGA Spatial Resolution) and the colour of each pixel would be 24 bits. So 640x480x24 = 7372800 bits. Which is around 7.4 Mb per image. 1Mb is equal to 10 to the power of 6 bits,

Dynamic Range:

The dynamic range of a visual scene is the number of colours of shades of grey or the (grey scale). The dynamic range of a digital image however is fixed by the number of bits or the (bit depth) the system uses to represent each pixel. This is what determines that the max number of colours or shades of grey in it's palette. The specific colours being uses form the image palette. 

1Bit Depth:

A pixel with a bit depth of one has two values. Black or white. As such to simulate the spacing of black white pixels a process using greys called half-tone is used.

Source: http://image.shutterstock.com/display_pic_with_logo/6049/6049,1290519588,1/stock-vector-halftone-rose-in-vector-format-65736655.jpg 

 

8 Bit Depth of Grey and 8 Bit Depth of Colour and True Colour:

In an 8-bit deep grey scale image every pixel has 256 possible shades of grey. In an 8-bit depth of colour image however 256 possible colours can be represented in pixels. In a true colour image 8 bits are used to code the intensities of the three colours. Each pixel as such can represent one of more than 16 million possible colours.

Colour Palette:

If the computer system determines the colour palette then the system palette colours 256 are used for every image. The fidelity of an of a 256 colour image is enhanced by selecting, for the palette, the 256 colours closest to the ones in the image. This is know as an adaptive palette and can cause problems when multiple images are displayed at the same time on a system which can only display 256 colours. The system than has to choose one palette and apply it to all the images shown.

Source: From Lecture

256 Colour Palettes:

Source: From Lecture

What is Digital Image Processing?

There are four common categories for DIP operations. These are analysis, manipulation, enhancement and transformation.

In analysis operations provide information of the photometric features of an image. These include a colour count and a histogram. In manipulation operations change the content of the image. This includes flood fill, crop. In enhancement operations attempt to improve the quality of an image. For example increasing the contrast, enhancing the edge and once more input image yields output image. Transformation operations alter the images geometry. For example rotation of the image. Again input image yields output image.

A Typical Digital Image Processing System:

Source: From Lecture

Analysis - The Histogram:

A common operation in term of analysis is the histogram. A display that plots intensity levels on the horizontal axis and the number of pixels having each level on the vertical axis. 

The histogram shown here is bi-modal. Pixels either have low low or high intensities but some have mid-range levels.

The histogram of an image that has good contrast alongside a good dynamic range will show a good use of the intensity range. Meanwhile the histogram of a low contrast image will show restricted use of the available intensity range. The histogram of an image that has very high contrast will show most of it's pixels either have incredibly low or high intensities. 

Transformation-Rotate:

The rotate transformation will rotate the image by 90 degrees or allow for rotation by free choice of angles. The first type of rotation is performed by remapping the pixel positions row for column. 

Free rotation requires interpolation algorithm is employed due to the rotating image may mean that a final pixel position may not lie uniquely on one output pixel. The interpolation works out an appropriate colour value in each pixel position in the output image. 

Manipulation-Block Fill:

Source: From Lecture

The area that is going to be changed is designated using a selection tool and afterwards is indicated via the marquee. Pixel addresses are tested and are modified by the chosen manipulation. In this case the block fill operation.

Enhancement-Filtering:

Filtering uses a kernel which moves the image over in small 1 pixel steps. At each step the kernel has parts that multiply the corresponding pixel value and are then totaled to come up with the new output pixel value.

Source: From Lectures

Enhancement - EX 1 Depth:

Source: From Lecture

Enhancement - Example 2: