Understanding Pixels: The Building Blocks of Digital Images

Pixels are the smallest units of digital images or graphics that can be displayed and represented on digital display devices. They are the basic building blocks of any visible element on a computer display, such as images, videos, and texts. In this article, we will explore what pixels are, how they work, and how they contribute to the quality and resolution of digital images.

The Fundamentals of Pixels

Pixels, also known as picture elements (pix = picture, el = element), are represented by dots or squares on a computer monitor display screen. They are created using geometric coordinates and are combined to form a complete image or visual element. The quantity, size, and color combination of pixels vary depending on the graphics card and display monitor, and are measured in terms of display resolution.

For instance, a computer with a display resolution of 1280 x 768 will produce a maximum of 98,3040 pixels on a display screen. The pixel resolution spread also determines the quality of the display. More pixels per inch of the monitor screen yield better image results.

Physical Size and Shape of Pixels

The physical size of a pixel varies depending on the resolution of the display. It will equal the size of the dot pitch if the display is set to its maximum resolution, and will be larger if the resolution is lower since each pixel will use more dots. As a result, individual pixels may become visible, leading to a blocky and chunky image defined as “pixelated.”

Pixels are uniformly arranged in a two-dimensional grid, although different sampling patterns are available. For example, in LCD screens, the three main colors are sampled at different locations of a staggered grid, while digital color cameras use a more regular grid.

In computer monitors, pixels are square-shaped, meaning that their vertical and horizontal sampling pitches are equal. In other systems, such as the anamorphic widescreen format of the 601 digital video standard, the shape of a pixel is rectangular.

Color and Pixels

Each pixel has a unique logical address, a size of eight bits or more, and, in most high-end display devices, the ability to project millions of different colors. The color of each pixel is determined by the specific blending of the three main components of the RGB color spectrum.

Depending on the color system, a different number of bytes can be allocated for specifying each color component of the pixel. For example, in 8-bit color systems, only one byte is allocated per pixel, limiting the palette to just 256 colors.

In the common 24-bit color systems used for nearly all PC monitors and smartphone displays, three bytes are allocated, one for each color of the RGB scale, leading to a total of 16,777,216 color variations. A 30-bit deep color system allocates 10 bits each of red, green, and blue for a total of 1.073 billion color variations.

However, since the human eye cannot discriminate more than ten million colors, more color variations do not necessarily add more detail, and may even lead to color banding issues.

Conclusion

Pixels are the fundamental building blocks of digital images, playing a crucial role in determining the quality and resolution of visuals on digital display devices. Understanding the nature of pixels and their interaction with color systems helps us appreciate the complexities and intricacies involved in creating and displaying digital images.