Image Resolution Introduction

Resolution is a parameter used to measure the amount of data in an image. Usually expressed as ppi (Pixel per inch per inch) and dpi (dots per inch). The more data you include, the larger the length of the graphics file and the richer details. But larger files also require more computer resources, more memory, more hard disk space, and more. On the other hand, if the image contains insufficient data (lower graphics resolution), it will appear rather rough, especially when the image is enlarged to a larger size. So during image creation, we have to decide the correct resolution based on the end use of the image. The trick here is to first ensure that the image contains enough data to meet the needs of the final output, but also to the right amount, to minimize the use of some computer resources.

Resolution is an important indicator when we buy digital cameras. Early years of digital camera resolution is very low, such as CASIO's QV-10 less than 100,000 pixels (320X240), 180,000 pixel KODAK DC20 (493X373) its resolution is not comparable to the current camera phone and camera. After nearly a decade of development, the resolution of digital cameras has been increasing, and now it has exceeded 10 million pixels. For the 2048X1536X16M, the 2048X1536 means 2048 pixels in the width direction and 1536 pixels in the height direction. 2048X1536=3145728, we call it 3 million pixels. The latter 16M refers to the color depth. Each pixel is colored, and the color of each pixel is recorded with 3 BYTEs, which are red, green, and blue. Each BYTE can record 256 levels, so a total of 256X256X256=16777216 different colors, ie 16M, also known as 24-bit color depth can be recorded. Therefore, if you record a 2048X1536 pixel image file in RGB color, you need 2048X1536X3=9437184 BYTE, which is 9MB, plus other information such as file header, which is ultimately greater than 9MB. However, most digital cameras usually use JPG format. This is a kind of image file format with distortion and compression. In general, 2048X1536 pixel JPG files have different file sizes according to their compression ratio, about 1-2MB. about. It is also possible to calculate the file size of other pixels such as 1600X1200X16M. It can be seen that the photos of 2048X1536X16M and 1600X1200X16M contain different numbers of pixels, which means that the information content is different. If you print the photo with the same output resolution, the size of the photo will be different. Conversely, if you output the same size photo, the number of pixels in the unit length is different, that is, the delicateness of the photo is Different.

Correct use of digital cameras to distinguish:

Resolution is an important parameter in digital cameras, and its value will directly affect the quality of the final image. At the same time, the higher the resolution of the image, the larger the size and size of the image, and the digital camera uses a memory card as a storage device, which will prevent you from saving more photos. How to find a balance between resolution and the amount of storage is a very difficult problem. If you strive for perfection, then you only have to add multiple memory cards or choose the right resolution for your photos.

First, the choice of advanced users:

Resolution is an important factor affecting the image effect, we generally use the number of pixels that can be displayed in the horizontal and vertical directions to represent the resolution, such as 1600 & times; 1200. The larger the value, the more disk space the graphics file occupies, and the details of the image behave more fully. So if you are a photographer or a perfectionist, then it is recommended that you choose the highest resolution when shooting. Although this will take up a lot of storage space and it will take some time to store, but these are beautiful images, everything is worth it. And large images leave you enough space for post-processing, large images can be properly scaled down, and small images are difficult to zoom in because the image information cannot be recovered. This way you have to prepare more memory cards. For these people, quality is the key.

The same print publishing also has high requirements for images. Generally, the minimum image accuracy is 300dpi (DotPerInch, which means the number of printed dots per inch. The higher the value, the printed image is also The more detailed and precise, the resolution of the picture should be at least 5 million pixels, which is 2560× 1920, which is only a professional camera to meet the requirements, the general digital camera is far behind. Of course, this choice is not unique, depending on the size of the photo on the layout and the number of lines printed.

Second, the choice of ordinary users:

Relatively speaking, if the pictures you take are only used for web page publishing, the requirements for resolution are much lower. 640× 480 resolution can meet the needs of most situations, and 1024x768 images are sufficient for post-touching, cropping and other operations. Similarly, the photos you take are only stored in the computer, and the above resolutions can also meet the requirements. It should be noted that the resolution of the image must be at least the resolution of the display or higher. If the picture you are taking is to be played on the projector in the future, then the image resolution must not be lower than the resolution of the projector.

Third, the choice of printing users:

But not all people are accustomed to just watching on a computer, or like traditional photos, then you need a higher resolution . Listed below are the sizes and minimum resolutions of our usual rinses:

Rinse 5" (3.5× 5) Photo: Pixels not less than 1024× 768;

Rinse 6" (4× 6 Photo: Pixels not less than 1280× 960;

Flush 12-inch (8× 12) photos: pixels are not less than 2272 & times; 1704;

The only required resolutions are listed here. It is generally best to increase one or two grades at the lowest resolution. For life photos and travel commemorative photos, the size of the general output photo is 5× below 7 inches, the best precision is 4 million pixels, which is 2272× 1704. In fact, whether using digital color expansion or color printer output, the feeling of 2 million pixels is not the same as that of the traditional camera. Of course, this is only for ordinary users, so if the storage space is limited, use 3 million or 200 pixels. It is also possible to shoot at a resolution.

At the same time, many digital cameras also provide storage formats for many images, which can meet the needs of different users. More commonly used are JPEG mode, TIF format, RAW format and so on. The JPEG method has information loss for the image, but its storage capacity is small, and the quality can also meet the basic needs, so the average user can select it. The other two formats do not compress the information, so the image quality is good, but the volume is huge. This is only recommended for advanced users. It should be noted that the resolution and format of the image are selected simultaneously, and the focus is different in different situations. For printouts, the high-resolution, low-precision mode works better than the low-resolution, high-precision mode. The picture is only viewed on a computer, the effect of the low-resolution high-precision mode is better than the high-resolution and low-precision mode, and the user can make a combination selection according to his own requirements. One key to choosing the resolution of the image in a digital camera is to choose according to your needs. Do not blindly pursue quality, or simply consider the amount of storage, everything from its own needs, in short, it is enough.