Computer Image Representation

What is a pixel and how is it used to represent an image?

• A pixel is a measurement of image brightness and has no role in representing an image

• A pixel is a type of computer virus that can corrupt images

• A pixel is the smallest unit of a digital image, and it is used to represent an image by combining multiple pixels to form the complete picture.

• A pixel is a unit of measurement for printed images, not digital ones

Explain the difference between raster graphics and vector graphics.

• Raster graphics are used for 3D images, while vector graphics are used for 2D images.

• Raster graphics have smooth edges, while vector graphics have pixelated edges.

• Raster graphics are black and white, while vector graphics are in color.

• Raster graphics are made up of pixels, while vector graphics are made up of paths and curves.

Name three common image file formats and describe their characteristics.

• JPEG, PNG, GIF

• MP3, MP4, WAV

• PDF, TIFF, BMP

• TXT, DOCX, PPTX

What is lossless compression and how does it work in image representation?

• Lossless compression only preserves half of the original data in the image

• Lossless compression removes some data from the image

• Lossless compression preserves all original data in the image.

• Lossless compression changes the color of the image

What is the purpose of lossy compression in image files?

• To increase file size by adding unnecessary image data

• To improve image quality by reducing pixel density

• To make the file incompatible with certain devices or software

• To reduce file size by permanently eliminating some image data

Explain the concept of color depth in relation to image representation.

• The brightness of the image

• The number of colors in the image

• The size of the image in pixels

• The number of bits used to represent the color of a single pixel in an image.

How does a computer use RGB values to represent colors in an image?

• By converting the RGB values to hexadecimal format

• By using black, white, and gray colors only

• By combining different intensities of red, green, and blue light

• By mixing red, yellow, and blue colors

Describe the process of converting an image from a raster format to a vector format.

• Using software to trace the raster image and convert it into mathematical lines and curves.

• Printing the image onto a transparent sheet and then scanning it into the computer

• Converting the image into a 3D model

• Manually redrawing the image using a pencil and paper

What are the advantages and disadvantages of using JPEG as an image file format?

• Advantages: Small file size, widely supported. Disadvantages: Lossy compression, artifacts in high compression.

• Advantages: Small file size, limited support. Disadvantages: Lossless compression, artifacts in high compression.

• Advantages: Large file size, limited support. Disadvantages: Lossy compression, no artifacts.

• Advantages: High file size, not widely supported. Disadvantages: Lossless compression, no artifacts.

Explain how the PNG file format supports transparency in images.

• By changing the file extension to .trans

• By adding a separate file for transparency data

• By adjusting the brightness of the image

• Using an alpha channel to vary levels of transparency