Photographers want everything. What does pixel mean?

I often meet many people who ask me what a pixel map is. Next, let's talk about what a pixel map is. I hope to study and discuss with you.

The full name of Pixel in Chinese is image element. Short for pixel, it refers to the basic original pigment and the basic coding of its gray level. Pixel is the basic unit of a digital image, and the resolution of the image is usually expressed in pixels per inch (PPI).

For example, a resolution of 300x300PPI means that the number of pixels per inch is 300 both horizontally and vertically, or it can mean that there are 90,000 (300x300) pixels per square inch.

Like photographic photos, digital images also have continuous shadows. If you enlarge the image several times, you will find that these continuous tones are actually composed of many small squares with similar colors, which are the smallest unit of the image-pixels. This smallest graphic unit usually displays a single coloring point on the screen. The higher the pixel, the richer the sample and the more realistic the color is.

When the picture size is in pixels, each centimeter is equal to 28 pixels. For example, a picture with a length of 15* 15 cm is equal to a length of 420*420 pixels.

At present, the pixel of the mainstream SLR digital camera is about1000000, but 5 million pixels is enough for ordinary photography and home use, because the resolution of the display we use is limited, generally from 1024×768 to 1920× 1200. If a picture with too many pixels is displayed at this resolution, the picture will be compressed to the size of the current screen.

Pixel, px, is the smallest point (unit color block) in the picture.

There is no fixed length value for pixel size, and the 1 unit pixel color block size is different on different devices.

Resolution = pixel value in the horizontal direction of the picture * pixel value in the vertical direction of the picture.

Screen resolution: the screen resolution is 1024×768, which means that the screen of the equipment has 1024 pixels in the horizontal direction and 768 pixels in the vertical direction. The size of a pixel has no fixed length, and the size of a unit pixel color block is different on different devices. For example, two screens with the same size and area can have different resolutions. The screen with high resolution has more pixels (color blocks), so the picture that can be displayed in the screen is more detailed and the area of a single color block is smaller. However, the low-resolution screen has fewer pixels (color blocks) and the area of a single pixel is larger, so the picture that can be displayed is not so detailed.

Image resolution: For example, the resolution of a picture is 500x200, that is to say, when the picture is enlarged by 1: 1 on the screen, there are 500 pixels (color blocks) in the horizontal direction and 200 pixels (color blocks) in the vertical direction. On the same device, the higher the picture resolution, the larger the picture area when the picture is enlarged at 1: 1. The lower the picture resolution, the smaller the picture area when the picture is scaled at 1: 1. (It can be understood that there is a one-to-one correspondence between the pixels of the picture and the pixels of the screen). However, when the picture is enlarged by more than 100% on the screen, why does the pixel color block on the picture become larger? In fact, the device supplements the image through an algorithm. The enlarged Fang Gezi we see is understood as an image pixel, but actually many screen pixels have been supplemented. Similarly, when the picture is reduced to less than 100%, the pixels of the picture are also reduced by algorithm. ? Finally, although the pixel block size will be different on different devices, the screen resolution and pixel block size on the same hardware device will not change.

The difference between the following two pictures with different pixels is obvious.

A picture is made up of dots one after another, and pixels, that is, dots, are the basic elements and the smallest units of an image. The enlarged image displays pixels, and the enlarged pixel image distorts the displayed pixels.