Computer Vision Basics Quiz

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Questions and Answers

What is the primary focus of computer vision?

To create 3-D models from 2-D images

To enable computers to identify and understand images and videos (correct)

To enhance image resolution

To develop new camera technologies

Which of the following accurately describes a 2-D image?

Represents objects in three dimensions

Lacks the depth dimension (correct)

Is captured using a lidar camera

Contains depth information

What is a significant reason for the widespread use of 2-D images in computer vision applications?

2-D capturing devices are more affordable and easier to access (correct)

2-D images provide more accurate depth representation

3-D capturing devices are universally available

3-D images are always superior

Which feature do 3-D image capture devices provide that 2-D devices do not?

Depth information Signup and view all the answers

What is a stereogram primarily used for?

To trick the brain into perceiving depth Signup and view all the answers

What is a disadvantage of 3-D capturing devices compared to 2-D capturing devices?

3-D capturing devices are often less accurate and more expensive Signup and view all the answers

Which of the following statements is true about computer vision?

It aims to automate tasks similar to human visual processing Signup and view all the answers

Why might a 3-D scanning device not be readily available for consumers?

They are costly and not commonly produced Signup and view all the answers

What is the first step to begin image processing in the provided instructions?

Install the necessary library Signup and view all the answers

Which function is used to read an image in grayscale format according to the instructions?

cv2.imread() Signup and view all the answers

What are the three primary colors used to measure color combinations in image processing?

Red, Green, Blue Signup and view all the answers

Which of the following best describes 'Radiance' in the context of color image processing?

Amount of energy that flows from a light source Signup and view all the answers

What is an incorrect statement about color perception?

Colors are perceived solely based on their wavelengths. Signup and view all the answers

In the context of electromagnetic energy, which range is considered visible light?

400 - 700 nm Signup and view all the answers

What does Luminance refer to in the characterization of light?

Energy perceived by an observer Signup and view all the answers

Which process is NOT mentioned as part of the steps for color image processing?

Normalizing image brightness Signup and view all the answers

What primary purpose does the YIQ color model serve?

Providing video information for monochrome TV Signup and view all the answers

Which of the following is a feature of the RGB to YIQ conversion matrix?

It allows for processing of luminance without affecting color Signup and view all the answers

What are the three components in the HSI color model?

Hue, Saturation, Intensity Signup and view all the answers

Why is it important to understand different color spaces?

They define reproducible representations of colors Signup and view all the answers

In the context of color representation, what does 'intensity' refer to in the HSI model?

The overall brightness of the color Signup and view all the answers

What does the grayscale colour model utilize to define colour?

Only one component: lightness Signup and view all the answers

Which of the following statements is true regarding the HS components in the HSI model?

They are well correlated with human visual sensitivity. Signup and view all the answers

What occurs during the RGB to HSI conversion process?

Color information is separated from brightness. Signup and view all the answers

What happens when histogram equalisation is applied to each colour plane in the RGB model?

The colours may change despite individual enhancement of R, G, or B Signup and view all the answers

What aspect of color space is particularly useful when working with image editing functions?

The need to convert images to required color spaces Signup and view all the answers

In which format are monochrome images typically represented?

In shades of gray or black-and-white Signup and view all the answers

What is the main limitation of the RGB colour model regarding image enhancement?

It may alter colours during individual plane enhancements Signup and view all the answers

How are grayscale images typically defined in terms of RGB values?

By equal values of red, green, and blue Signup and view all the answers

What does the HSV color model represent?

Hue, saturation, and value Signup and view all the answers

Which hue is represented by the degree range of 181 to 240 degrees in the HSV model?

Cyan Signup and view all the answers

What is the purpose of the RGB colour model?

To reproduce a broad array of colours through additive mixing Signup and view all the answers

What does each gray level in a grayscale image represent?

A distinct intensity of lightness Signup and view all the answers

How does saturation affect a color in the HSV model?

It introduces more gray into the color. Signup and view all the answers

Which of the following statements is true regarding the channels of a monochrome image?

It consists of a single channel for black-and-white values Signup and view all the answers

Why do designers prefer the HSV color model over the RGB model for color selection?

It better represents how people relate to colors. Signup and view all the answers

What does the process of image sampling refer to in the digital representation of images?

Representing the image through pixel values in a matrix Signup and view all the answers

What is the maximum value for quantised 𝑓(𝑥, 𝑦) in a typical 8-bit image representation?

255 Signup and view all the answers

What is the main purpose of the K (Key) channel in the CMYK color model?

To determine the image outcome as a key component Signup and view all the answers

What does Value represent in the HSV model?

The brightness or intensity of the color Signup and view all the answers

Which function is used to load an image from a specified file in OpenCV?

cv2.imread() Signup and view all the answers

What happens if the cv2.imread() method fails to load an image?

It returns an empty matrix Signup and view all the answers

What does a saturated value of 0 imply in the HSV model?

The color is fully gray Signup and view all the answers

When converting from RGB to CMY, what does the formula for C (Cyan) indicate?

C = 255 - R Signup and view all the answers

In an image representation using a 2-dimensional array in C language, what is an appropriate data type for storing pixel values?

unsigned char f[N][M] Signup and view all the answers

Which of the following statements is true regarding the image representation matrix after sampling?

Values are usually quantised into integers ranging from 0 to 255 Signup and view all the answers

What is the primary purpose of the flag parameter in the cv2.imread() function?

To determine how the image should be read Signup and view all the answers

Which of the following best describes the result of the image after digitisation through gray-level quantisation?

It consists of discrete pixel values in a defined range Signup and view all the answers

Study Notes

Colour Image Processing

Colour image processing is the study of how colours are represented, processed, and displayed.
Computer vision is a field of computer science enabling computers to identify and understand objects in images and videos.
Computer vision aims to replicate human capabilities.

2-D or 3-D Images

2-D images lack depth.
3-D images have depth information.
2-D image capture devices include cameras.
Examples of 3-D image capture devices include lidar cameras and kinect cameras.

3D Stereogram

A stereogram can create a 3D illusion by tricking the brain into perceiving depth using overlapping images.

Image for Computer Vision

Current computer vision applications largely rely on 2-D images due to their accessibility and readily available 2-D capture devices.
3-D capturing devices are less accessible and more expensive.
2-D applications include X-ray analysis and image recognition.
3-D applications include self-driving cars and autonomous robots.
This study focuses on 2-D images.

Image Representation

Original images (f(x, y)) are continuously valued functions in the 2-D X-Y domain with amplitude.
Digital images are digitised spatially in the 2-D X-Y domain (sampling) and in amplitude (quantization).
This digitisation results in a matrix representation where pixel values are integers ranging from 0 to 255.

Image Representation in Matrix

After sampling, an image (f(x, y)) is represented as an N x M array.
Pixel values are typically quantized to integers between 0 and 255 for efficient storage.
In programming languages like C, images can be stored as 2-dimensional arrays, commonly using unsigned char data types.
It is possible for images to take on continuous values using float data type in the array.

Colour Models

Colour is perceived from light reflected from an object.
Visible light is composed of frequencies: approximately 400 to 700 nm.
Quantities used to describe chromatic light source include radiance (watts) luminance (lumens) and brightness (subjective).

RGB

Colours can be reproduced by combining red (R), green (G), and blue (B) colours.
This is an additive color model.
RGB is mainly used for hardware like monitors and video cameras, whereas CMY is used for printed outputs.

CMY

Primary pigment colours for pigments are Cyan (C), Magenta (M), and Yellow (Y).
This is a subtractive color model, meaning they absorb or subtract one colour.
CMYK (with key/black) is also prevalent and is used in printing applications.

YIQ

Used in commercial colour TV broadcasting
Maintains compatibility with monochrome TV standards.
The Y component represents luminance.
The I and Q components represent chrominance.
This is designed for the human visual system (HVS). This decoupling allows image processing to be done on luminance without affecting the color components.

HSI

Decoupling of colour (chrominance) from intensity (luminance).
Hue (attribute to describe pure color), saturation (degree to which pure color is diluted by white light), and intensity (brightness) make up the HSI model.
Common in image processing applications.

RGB to HSI Conversion

Formulations exist to translate RGB to HSI color model.
Key formulas involve calculations based on normalized values of R, G, and B.
The intensity (I) is the average of R, G, and B values.
Saturation (S) describes how much white is mixed with the pure color.
Hue (H) describes the color's position on the color wheel.

HSV

HSV stands for (hue, saturation, value).
HSV describes colors using hue, saturation, and value.
Hue is the color itself (a number between 0 and 360 degrees).
Saturation is a measure of color intensity (how pure the color is).
Value is a measure of light intensity (brightness or intensity).
HSV (and HSI) are often used in image-editing software.

Converting to different Color Space using `cv2.cvtColor`

cv2.cvtColor converts images between color spaces (e.g., RGB to grayscale, RGB to HSV).
The function takes an image as input and the desired conversion code.

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Description

Test your understanding of computer vision concepts and image processing techniques with this quiz. Questions cover various aspects such as 2-D and 3-D images, stereograms, and color perception. Discover how these elements come together in the field of computer vision.