Data Representation: Text, Sound And Images: Understand How And Why A Computer Represents An Image, Including The Effects Of The Resolution And Colour Depth (Copy)
| Concept | Computer Representation Of Images |
|---|---|
| Why Images Are Encoded | Computers only store binary data |
| Image Type | Images are represented as bitmaps (raster images) |
| Structure | Image made of tiny squares called pixels |
| Pixel | Smallest unit of an image |
| Pixel Representation | Explanation |
|---|---|
| Pixel Value | Binary number representing a colour |
| Storage | Each pixel stored individually |
| Image Quality | Depends on number of pixels and bits per pixel |
| Resolution | Key Details |
|---|---|
| Definition | Number of pixels in an image (width × height) |
| Example | 800 × 600 |
| Effect On Quality | Higher resolution = more detail |
| Effect On File Size | Higher resolution = larger file |
| Resolution Comparison | Low Resolution | High Resolution |
|---|---|---|
| Number Of Pixels | Few | Many |
| Image Sharpness | Blurry | Clear |
| Storage Required | Small | Large |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Computer Science Full Scale Course
| Colour Depth | Key Details |
|---|---|
| Definition | Number of bits used to represent each pixel |
| Also Called | Bit depth |
| Effect On Colours | Higher depth = more colours |
| Effect On File Size | Higher depth = larger file |
| Colour Depth Examples | Bits Per Pixel | Number Of Colours |
|---|---|---|
| Black & White | 1 | 2 |
| Greyscale | 8 | 256 |
| True Colour | 24 | 16.7 million |
| Colour Depth Effect | Explanation |
|---|---|
| Low Colour Depth | Colour banding, limited shades |
| High Colour Depth | Smooth colour transitions |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Computer Science Full Scale Course
| Resolution vs Colour Depth | Resolution | Colour Depth |
|---|---|---|
| Controls | Image detail | Colour accuracy |
| Increases | Pixel count | Colours per pixel |
| File Size Impact | High | High |
| Image File Size Depends On | Factor |
|---|---|
| Resolution | Number of pixels |
| Colour Depth | Bits per pixel |
| Compression | Lossy or lossless |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Computer Science Full Scale Course
| Common Examiner Traps | How To Avoid |
|---|---|
| Confusing resolution and size | Define resolution clearly |
| Forgetting colour depth | Always mention bits per pixel |
| Saying “better quality” only | Explain why |
| Ignoring storage impact | Mention file size |
| One-Line Summary | Exam-Perfect Statement |
|---|---|
| Image Representation | Images stored as pixels with binary values |
| Resolution | Affects image detail |
| Colour Depth | Affects colour range |
Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Computer Science Full Scale Course