Why should we care about the concept of pixels?

A pixel is the smallest unit of a digital image, representing a single point in a raster graphics display. It is short for "picture element" and is used to describe the basic building blocks of digital images.

Pixels have values that represent the colour and brightness of the point they represent in the image. In most cases, the colour of a pixel is determined by a combination of three primary colours: red, green, and blue. These values are usually represented as numbers ranging from 0 to 255, where 0 represents no colour or brightness, and 255 represents the maximum colour or brightness value.

For example, a pixel with a value of (255, 0, 0) would be fully saturated in red and have no green or blue. A pixel with a value of (127, 127, 127) would be a neutral grey.

The values of a pixel are often stored as integers, but they can also be represented as floating-point numbers. Floating-point numbers are used to represent real numbers with a fractional component, such as decimal numbers. They offer greater precision than integers, which can be important in certain applications, such as medical imaging or scientific research.

In some cases, such as in medical imaging or scientific applications, pixels may have values that represent something other than colour, such as intensity or energy levels. In these cases, the values of a pixel may not necessarily correspond to a specific colour but rather to a specific numerical value that represents the property being measured.

In some cases, floating-point numbers are used to represent the values of pixels in order to increase the dynamic range of the image. The dynamic range refers to the range of brightness levels that can be captured or displayed by a device. By using floating-point numbers, the range of possible values for each pixel can be increased, allowing for a greater range of brightness levels to be represented in the image.

Usually, pixel values are expressed as whole numbers, where each colour channel has a range between 0 and 255. The reason for this is that the majority of digital images are in the RGB colour space, which only allows for specific values between 0 and 255 for each channel.

To put it briefly, pixels serve as the fundamental units of digital images and their values indicate the shade and luminosity of the area they portray. Although pixel values are usually denoted as integers ranging from 0 to 255, they can also be expressed as floating point numbers in specific situations, enabling greater precision and accuracy for scientific or mathematical computations.

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ref

https://www.wavemetrics.com/code-snippet/putting-pixel-values-image