UNIT-5

Basics of Pixels 

The word “pixel” means a picture element. Every photograph, in digital form, is made up of pixels. They are the smallest unit of information that make up a picture. Usually round or square, they are typically arranged in a 2-dimensional grid. 

Image resolution

it refers to the number of pixels that exist within that image. The higher the resolution, and the richer the pixel count, the more detail and definition you will see. 

The number of pixels in an image is sometimes called the resolution. When the term is used to describe pixel count, one convention is to express resolution as the width by the height, for example a monitor resolution of 1280×1024. This means there are 1280 pixels from one side to the other, and 1024 from top to bottom 

The resolution of a digital image is measured using its pixels; specifically in pixels per inch (PPI). For printing, picture resolution is measured by dots per inch (DPI), referring to the tiny droplets of ink that printers create. 

• The higher the image resolution, the more pixels are bunched together — which creates a smoother, more detailed image.

• The phrase ‘high-resolution’ is often used synonymously with quality — as vivid, crisp images are what we typically associate with good photography. However, it’s important to remember that resolution is just one factor that can affect image quality.

RGB Images 

All the images that we see around are coloured images. These images are made up of three primary colours Red, Green and Blue. All the colours that are present can be made by combining different intensities of red, green and blue 

Grayscale images:

A kind of black-and-white or gray monochrome, are composed exclusively of shades of gray.  The darkest possible shade is black, which is the total absence of colour or zero value of pixel. The lightest possible shade is white, which is the total presence of colour or 255 value of a pixel .  

The contrast ranges from black at the weakest intensity to white at the strongest.

Introduction to OpenCV 

Open Source Computer Vision Library is that tool which helps a computer extract these features from the images. It is used for all kinds of images and video processing and analysis. It is capable of processing images and videos to identify objects, faces, or even handwriting. 

To install OpenCV library, open anaconda prompt and then write the following command: pip install opencv-python 

Activities: 

● Game- Emoji Scavenger Hunt https://emojiscavengerhunt.withgoogle.com/ 

● RGB Calculator: https://www.w3schools.com/colors/color s_rgb.asp

 ● Create your own pixel art: www.piskelapp.com

 ● Create your own convolutions: http://setosa.io/ev/image-kernels/