What is a pixel?

Resolution is a parameter used to measure the amount of data in a bitmap image, usually expressed in pixels. Simply put, the resolution of the camera refers to the ability of the camera to analyze images, that is, the number of pixels of the camera's image sensor. The highest resolution refers to the size of the camera's ability to distinguish images at the highest level, that is, the maximum number of pixels of the camera. At present, the maximum resolution of 300,000-pixel CMOS on the market is generally 640,480 pixels, and the maximum resolution of 500,000-pixel CMOS is generally 800,600 pixels. The two digits of the resolution represent the point units of the length and width of the picture. The aspect ratio of digital pictures is usually 4: 3.

In practical application, the higher the pixel of the camera, the better the image quality, but conversely, the higher the pixel, the better. The higher the pixels of the same picture, the stronger its ability to analyze the image, but the amount of data it records will be much larger, so the requirements for storage equipment are much higher.

In fact, these camera pixels are all improved by software interpolation. For example, to put it simply, the 640X480 picture is enlarged to 1024X768, and then the color difference between the resolution points of the picture is calculated by software, and the middle enlarged part is filled with the color calculated by software. Although the output image is large, the image quality has not been really improved effectively, and even serious distortion may occur.

It is worth noting that some resolution marks refer to the interpolation resolution that these products can achieve by using software. Although it can also improve the accuracy of image acquisition, there is still a certain gap compared with the hardware resolution.

Therefore, when you buy a camera, you must remember that there is no absolute relationship between the pixel level of the camera and the clarity of the image. Especially those cameras with hundreds or even tens of millions of pixels interpolated by software, the actual effect is likely to be similar to hundreds of thousands of pixels. Generally speaking, whether the image is clear or not depends on the pixels, but it is also closely related to the lens material and software processing.

Some technical indexes of cameras

1, image resolution/resolution:

SXGA( 1280 x 1024) is also called 1.3 million pixels.

XGA( 1024 x768) is also called 800,000 pixels.

SVGA(800 x600) is also called 500,000 pixels.

VGA(640x480) is also called 300,000 pixels (350,000 refers to 648X488).

CIF(352x288) is also called 65438+ megapixels.

SIF/QVGA(320x240)

QCIF( 176x 144)

QSIF/QQVGA( 160x 120)

2. Image format/color space.

RGB 24 and I420 are the two most commonly used image formats at present.

RGB 24:R, G and B have 8 bits each, which can represent 256 colors at most, so that 256*256*256 colors can be reproduced.

I420: One of YUV formats.

Other formats are: RGB565, RGB444, YUV4:2:2, etc.

National football and camera: the national football is not credible, but sometimes it has to be watched; Camera pixels are even more unreliable, and sometimes you have to buy them! In a word, keeping your eyes open and choosing rationally is the best choice at present.