Pixel, resolution, PPI (pixel density), BPP literacy

Pixel at resolution

Pixels, Also knownPainterIs the basic unit for image display.Pixel",PIXIs a commonly used abbreviation of the English word picture, plus the English word "element"ElEment.PixelTherefore, "pixels" indicate the meaning of "image elements", which are also calledPel(PIctureEl). Each such information element is not a point or a square, but an abstract sample. After careful processing, pixels in an image may not look like separated vertices or squares at any scale, but in many cases they are displayed in dots or squares. Each pixel can have its own color value, which can be displayed in three primary colors and thus be divided into three types: Red, green, and blue.Sub-pixel(RGB Color Gamut), or green, magenta, yellow, or black (CMYK color gamut, common in the printing industry and printers ). A photo is a collection of sample points. The larger the number of pixels per unit area indicates a higher resolution, without incorrect/lossy compression or camera lenses, the displayed image is close to the real object.

A pixel is usually regarded as the minimum Complete sampling of an image.

 

PPI

PPI:Pixels per inch(English:PIxelsPErINCH, Abbreviation:PPI), Also knownPixel densityIs an index that indicates the number of pixels on a printed image or display per unit area. It is generally used to measure the precision of the screen of computer monitors, televisions, and handheld electronic devices. In general, the higher the pixel value per inch, the finer the image displayed on the screen.

For example, if the resolution of a 5-inch mobile phone is 1280*720, the calculated PPI is 293.

 

BPP:

Color DepthThe field of computer graphics indicates the number of digits used to store one pixel of color in a bitmap or video frame buffer, also known as BPP ). The higher the color depth, the more colors available.

The color depth is illustrated by "N-bit color. If the color depth is N bits, there are 2n color options, and the number of BITs for storing each pixel is N. Common examples include:

• 1: two colors, monochrome, black and white, used for compact mac1_shes.
• 2 bits: Four Colors, CGA, used for nextstation and color mac1_shes in the early gray-scale period.
• 3-digit: 8 colors for most early computer displays.
• 4-digit: 16 colors, used for Gbit/s and unusual VGA standards at higher resolutions, color macstmshes.
• 5 bits: 32 colors for original Amiga chipset.
• 6 bits: 64 colors for original Amiga chipset.
• 8 digits:
  • 256 colors for the earliest color Unix workstation, low-resolution VGA, super VGA, Aga, color macstmshes.
  • Gray scale, with 256 gray (including black and white ). If it is expressed in 24-Bit mode, the RGB values are the same, for example (200,200,200 ).
  • Color Image, if expressed in 24-Bit mode, the RGB values are the same, for example (200,200,200 ). It is often said that 24 real colors, about 16.7 million colors.
• 12-bit: Used in some Silicon Valley graphics systems, Neo GEO, color nextstation and Amiga systems in ham mode.
• 16 bits: used for some color mac1_shes.
• 24 bits: about 1.07 billion colors, true color, can provide more colors than the naked eye, used to take photos.

In addition, there is a high-dynamic range image, which uses more than 256 levels of color to store images, generally, each pixel is allocated with 32 + 32 + 32 bits to store color information. That is to say, each primary color is stored with a 32-bit floating point number.

Pixel, resolution, PPI (pixel density), BPP literacy