What does pixel mean and what are its application fields?

Pixels are just a unit of size for resolution, not image quality. So how much do you know about pixels? The following is what I have compiled about what a pixel is. I hope you like it!

Definition of pixel

Pixel: refers to a pixel represented by a sequence of numbers The smallest unit in an image is called a pixel.

Instead of the original entry saying that the image is composed of dots, these dots are called pixels.

Application fields of pixels

Digital cameras

Pixels are the most important indicator for measuring digital cameras.

Pixels refer to the resolution of a digital camera.

It is determined by the number of photosensitive elements on the photoelectric sensor in the camera. One photosensitive element corresponds to one pixel. Therefore, larger pixels mean more photosensitive elements, and the corresponding cost is greater. The image quality of a digital camera is partly determined by pixels. It is meaningless to simply compare pixels if it is larger than a certain size. The pixels of mainstream SLR digital cameras are around 10 million, but 5 million pixels is enough for ordinary photography and home use. The resolution of the monitor we use is limited, generally 1024?768 to 1920?1200. If a picture with too high pixels is displayed at this resolution, the picture will be compressed to the size of the current screen, and some pictures will appear at this time. Distortion occurs when the sharpness is too high. Image quality mainly depends on the camera lens, sensor size and quality.

The larger the pixels, the larger the resolution of the photo and the larger the printable size. However, early digital cameras were all less than 1 million pixels. Starting from the second half of 1999, 2-megapixel products gradually became the mainstream of the market. (Mobile phones generally have 2 million pixels, and ordinary digital cameras generally have more than 3 million pixels.)

The current development trend of digital cameras is that the pixels are like the CPU frequency of a PC, with larger and larger pixels. momentum. In fact, from the perspective of market classification, for popular products, considering cost-effectiveness, bigger pixels are not always better. After all, 2 million pixel products can already meet most applications of ordinary consumers.

Therefore, while most manufacturers are pursuing high pixels in high-end digital cameras, their current largest output is still the universal megapixel product. Top-level dedicated cameras, with products exceeding 100 million pixels. It is also worthy of consumers' attention that the current digital camera products are divided into CCD pixels and software-optimized pixels in terms of pixel nominal, and the latter is much higher than the former. For example, the CCD of a popular digital camera of a certain brand has 2.3 million pixels, but the pixels after software optimization can reach 3.3 million.

The pixels of digital cameras are divided into the maximum number of pixels and the effective number of pixels.

Maximum pixels

The English name is Maximum Pixels. The so-called maximum pixels are obtained after interpolation operations. The interpolation operation is through the DSP chip located inside the digital camera. When the image needs to be enlarged, operations such as nearest neighbor interpolation and linear interpolation are used to add the additional pixels required after the image is enlarged. The image quality obtained after interpolation operation cannot be compared with the image of real photosensitive imaging.

On the market, some merchants will indicate that "up to The speed is not as good as that shot with effective pixels.

Maximum pixels also directly refer to the pixels of CCD/CMOS photosensitive devices. In order to increase sales, some businesses only advertise the maximum pixels of digital cameras. When setting the picture resolution of digital cameras, there are indeed shooting The highest pixel resolution picture. However, users should be aware that this is a value obtained through the internal calculation of the digital camera. When printing the picture, the loss of image quality will be very obvious.

Effective pixels

The English name of the number of effective pixels is Effective Pixels. Different from the maximum pixels, the effective number of pixels refers to the pixel value that actually participates in photosensitive imaging. The highest pixel value is the real pixel of the photosensitive device. This data usually includes the non-imaging part of the photosensitive device, and the effective pixel is the value converted at the zoom magnification of the lens. Taking Minolta's DiMAGE7 as an example, its CCD has 5.24 million pixels (5.24 Megapixel). Because part of the CCD does not participate in imaging, the effective pixels are only 4.9 million.

Digital images are generally stored in pixels, and each pixel is the smallest unit of area in a digital image. The larger the pixels, the larger the image area. To increase the size of a picture, if no more light enters the photosensitive device, the only way is to increase the area of ??the pixels, which may affect the sharpness and clarity of the picture. Therefore, when the pixel area remains unchanged, the largest picture pixel a digital camera can obtain is the effective pixel.

When users buy digital cameras, they usually see merchants advertise that the maximum pixels reach XXX and the effective pixels reach XXX. So what should users choose? When choosing a digital camera, they should Pay attention to the effective pixels of the digital camera. The number of effective pixels is the key to determining the quality of the picture.

TV pixels

The functions of TV pixels in the TV system are:

(1) Determine the image clarity. The smaller the pixels are divided into, the more total pixels there are in the picture and the clearer the image will be.

(2) Facilitate television transmission of images. Scanning can be used to extract image information point by point and convert it into transmittable electrical signals.

(3) Convenient for TV display. No matter what form of imaging is used, the image points can be restored point by point by scanning.

Pixel painting

Pixels are actually composed of many dots. The "pixel art" we are talking about here is not the bitmap image corresponding to the vector image, but refers to an icon-style image. This style of image emphasizes clear outlines and bright colors. At the same time, the shape of the pixel image is often relatively Cartoon, so it is loved by many friends. The production method of pixel graphics rarely uses the aliasing method to draw smooth lines, so the .gif format is often used, and the pictures often appear in dynamic form. However, due to its special production process, if the size of the picture is changed at will, the style will be difficult to Guaranteed.

The application range of pixel art is quite wide, from the pictures of the FC home red and white machine when I was a child to today’s GBA handheld machine; from the black and white mobile phone pictures to today’s full-color handheld computers; even though we use The computers we face are also filled with pixel icons of various software. Nowadays, pixel painting has become an art, which deeply shocks you and me.

Introduction to pixel values

The pixels mentioned by the camera actually mean the maximum pixels. The pixel is the unit of resolution. This pixel value is only the effective maximum resolution supported by the camera. Rate.

300,640?480

500,800?600

801,024?768 5? (3.5?5 inches)

1.3 million 1280? 960 6? (4? 6 inches)

2 million 1600? 1200 8? (6? 8 inches) 5? (3.5? 5 inches)

310 10,048?1536 10?(8?10 inches) 7?(5?7 inches)

4.3 million 2400?1800 12?(10?12 inches) 8?(6?8 inches)

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5 million 2560?1920 12?(10?12 inches) 8?(6?8 inches)

6 million 3000?2000 14?(11?14 inches) 10?(8 ?10 inches)

8 million 3264?2488 16?(12?16 inches) 10?(8?10 inches)

11 million 4080?2720 20?(16?20 inches) 12? (10? 12 inches)

14 million 4536? 3024 24? (18? 24 inches) 14? (11? 14 inches)

Overview of raw pixels< /p>

Because the resolution of most computer monitors can be adjusted through the computer's operating system, the monitor's pixel resolution may not be an absolute measure. Modern LCD monitors are designed to have a native resolution, which represents a perfect match between pixels and groups of elements. (Cathode ray tubes also use red-green-blue fluorescent three-element groups, but they do not coincide with the image pixels, so they cannot be compared with the pixels).

For this monitor, native resolution produces the most detailed images. But because the user can adjust the resolution, the monitor must be able to display other resolutions. Non-native resolutions must be achieved by fitting resampling on the LCD screen, using an interpolation algorithm. This often makes the screen look broken or blurry.

For example, a display with a native resolution of 1280?1024 looks best at a resolution of 1280?1024, or it can be represented by several physical triples to represent a pixel to display 800?600 , but it may not be able to fully display the resolution of 1600~1200 because the physical trio is not enough. Pixels can be rectangular or square. There is a number called the aspect ratio, which is used to express how many pixels there are.

For example, an aspect ratio of 1.25:1 means that the width of each pixel is 1.25 times its height. Pixels on computer monitors are usually square, but pixels used in digital imaging have a rectangular aspect ratio, such as those used in PAL and NTSC, variants of the CCIR 601 digital imaging standard, and their corresponding widescreen formats. Each pixel of a monochrome image has its own grayscale. 0 usually means black, while the maximum value usually means white.

For example, in an 8-bit image, the largest unsigned number is 255, so this is the white value.

In color images, each pixel can be represented by its hue, saturation, and brightness, but is usually represented by its red, green, and blue intensity (see RGB).