COMPUTING IMAGE

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Questions and Answers

What is a primary characteristic of JPEG compression?

It can be reversed after compression.

It is lossless and retains all original data.

It is the only format used for compressing images.

It permanently deletes some image data during compression. (correct)

Which of the following formats is known for lossless compression?

TIFF

GIF

JPEG

PNG (correct)

What type of metadata includes details like file type and creation date?

Structural metadata

Administrative metadata (correct)

Rights metadata

Descriptive metadata

What is the process of converting analogue signals to digital signals called?

Digitization Signup and view all the answers

Which of the following correctly outlines the stages of digitization?

Sampling and quantization Signup and view all the answers

How does structural metadata function?

It organizes and categorizes objects within a larger system. Signup and view all the answers

What characteristic distinguishes lossy compression from lossless compression?

Lossy compression results in permanent data removal. Signup and view all the answers

What is quantization in the context of digitization?

Mapping measured samples to digital values. Signup and view all the answers

How does the number of bits affect the range of colors that can be represented in an image?

Each extra bit doubles the range of colors. Signup and view all the answers

Which system is used by computers to represent colors on digital display screens?

RGB Signup and view all the answers

What is the maximum value for each component in the RGB color model?

255 Signup and view all the answers

How does the bitrate relate to image quality?

Higher bitrate allows for more data to recreate images effectively. Signup and view all the answers

What is the meaning of image resolution?

The clarity of an image expressed in pixels per inch. Signup and view all the answers

What would likely happen to the image quality if the color depth is reduced?

Image quality would suffer due to limited color representation. Signup and view all the answers

Which of the following image formats is NOT commonly known?

XYZ Signup and view all the answers

What does each pixel of an image represent?

A single color defined by its depth. Signup and view all the answers

Which statement accurately describes pixelation in images?

Pixelation happens when an image is zoomed in due to a lack of pixels. Signup and view all the answers

What characteristic differentiates vector images from bitmap images?

Vector images are mathematically defined objects. Signup and view all the answers

How does increasing image resolution affect the file size?

Higher resolution increases file size. Signup and view all the answers

What does the term 'color depth' refer to in relation to images?

The number of bits allocated for each pixel in an image. Signup and view all the answers

What is the maximum number of colors that can be represented with a bit depth of 4 bits?

16 colors Signup and view all the answers

What occurs to the appearance of a low-resolution image when it is enlarged?

It appears more blocky and blurry. Signup and view all the answers

What defines the standard size range for vector images?

1000 x 1000px to 4800 x 4800px Signup and view all the answers

Which of the following equations would you use to calculate the file size of an image?

Width x Height x Color Depth Signup and view all the answers

Study Notes

Vector and Bitmap Images

Vector images are formed using objects and their properties, storing information to create images.
Vector images are resolution independent and use algorithms instead of pixels.
Bitmap images are created using cameras and are resolution dependent, meaning the quality is determined by the number of pixels.
Zooming into bitmap images results in pixelation as individual pixels become visible.
Vector images are mathematically defined and don't suffer from pixelation when enlarged.

Image Resolution

Image resolution refers to the detail in an image and is measured in pixels per inch (ppi).
Higher resolution images have more pixels and appear sharper when enlarged.
Low-resolution images look blocky or pixelated when enlarged due to larger pixels.
Higher resolution images result in larger file sizes.

Pixels and Bits

Each pixel stores a certain number of bits, known as bit depth.
Higher bit depth allows for more colours to be represented.
More colours require more bits per pixel, leading to larger file sizes.
A bit depth of 8 allows for 256 colours, while 2 bits represent 4 colours.

How Computers Detect Images

Computers use binary sequences of 1's and 0's to represent images.
Algorithms and machine learning techniques are used to identify colours and objects.
Images are represented as a grid of pixels, each containing a colour defined by a specific binary pattern.

Colour Detection

Human eyes detect different wavelengths of light: red (long), green (medium), and blue (short).
Computers represent these colours using RGB (Red, Green, Blue).
Each colour component in RGB has a value from 0 to 255.
RGB lighting combines red, green, and blue light to create a wide range of colours.

Image Quality and Bits

Image resolution affects image clarity on a screen.
Bitrate refers to bits per second, representing the amount of data used to recreate an image.
A higher bitrate provides more data and results in higher quality images.
Larger colour depths (more bits per pixel) allow for more colours and generally improve image quality.

Image Formats

Images can be saved in various formats, including JPEG, PNG, BMP, GIF, and TIFF.
JPEG allows for lossy compression, where data is removed, resulting in a smaller file size but some quality loss.
PNG is a lossless format, retaining all image data and resulting in larger file sizes.
TIFF, GIF, and BMP are all examples of raster image formats.

Metadata

Metadata is data about data, providing information about a file.
Administrative metadata includes file type, creation date, and author.
Image metadata includes information like image dimensions, resolution, colour depth, and capture time.
Structural metadata categorises an object, establishing relationships with other files.

Analogue to Digital Conversion

Analogue signals must be converted to digital signals for storage in digital devices.
Digitization involves sampling and quantization.
Sampling involves taking frequent measurements of the analogue signal at regular intervals.
Quantization maps the sampled measurements to a set of digital values.
An ADC (Analogue-to-Digital Converter) performs this conversion.