The mobile phone market is filled with huge resolution camera models. There are even relatively inexpensive smartphones with sensors with a resolution of 16-20 megapixels. An ignorant buyer chases a “cool” camera and prefers a phone with a higher camera resolution. He does not even realize that he is falling for the bait of marketers and sellers.
What is permission?
Camera resolution is a parameter that indicates the final image size. It only determines how large the resulting image will be, that is, its width and height in pixels. Important: image quality does not change. The photo may turn out to be of poor quality, but large due to the resolution.
Resolution does not affect quality. It was impossible not to mention this in the context of the interpolation of the smartphone camera. Now you can go directly to the point.
What is camera interpolation in a phone?
Camera interpolation is an artificial increase in image resolution. It is the image, not the size of the matrix. That is, this is special software, thanks to which an image with a resolution of 8 megapixels is interpolated to 13 megapixels or more (or less).
If we draw an analogy, then interpolating the camera is like a magnifying glass or binoculars. These devices enlarge the image, but do not make it better or more detailed. So if interpolation is indicated in the characteristics of the telephone, then the actual resolution of the camera may be lower than stated. This is not bad and not good, it just is.
What is it for?
They came up with interpolation to increase the size of the image, nothing more. Now this is a ploy of marketers and manufacturers who are trying to sell a product. They indicate in large numbers on the advertising poster the resolution of the phone’s camera and position it as an advantage or something good. Not only that, the resolution itself does not affect the quality of the photographs, so it can still be interpolated.
Literally 3-4 years ago, many manufacturers were chasing the number of megapixels and in various ways tried to shove them into their smartphones with as many sensors as possible. So there were smartphones with cameras with a resolution of 5, 8, 12, 15, 21 megapixels. At the same time, they could take pictures like the cheapest soap dishes, but buyers, seeing the sticker "18MP Camera", immediately wanted to buy such a phone. With the advent of interpolation, it has become easier to sell such smartphones because of the ability to artificially add megapixels to the camera. Of course, the quality of the photo began to grow over time, but certainly not because of resolution or interpolation, but because of natural progress in terms of developing sensors and software.
Technical side
What is camera interpolation technically in the phone, because all the text above described only the main idea?
Using special software, new pixels are "drawn" on the image. For example, to enlarge the image by 2 times, a new line is added after each row of pixels in the image. Each pixel in this new row is filled with color. The fill color is calculated by a special algorithm. The very first way is to fill in the new line with the colors that the nearest pixels have. The result of such processing will be terrible, but such a method requires a minimum of computational operations.
Most often, another method is used. That is, new lines of pixels are added to the original image. Each pixel is filled with color, which, in turn, is calculated as the average value of neighboring pixels. This method gives better results, but requires more computational operations.
Fortunately, modern mobile processors are fast, and in practice, the user does not notice how the program edits the image, trying to artificially increase its size.
There are many advanced interpolation methods and algorithms that are constantly being improved: the borders of the transition between colors are improved, the lines become more accurate and clear. It doesn't matter how all these algorithms are built. The very idea of camera interpolation is commonplace and is unlikely to take root in the near future. Using interpolation, it is impossible to make the image more detailed, add new details or improve it in any other way. Only in films does a small blurry picture after applying a couple of filters become clear. In practice, this cannot be.
Do you need interpolation?
Many users, out of their ignorance, ask questions on different forums on how to interpolate the camera, believing that this will improve image quality. In fact, interpolation will not only not improve the quality of the image, but may even make it worse, because new pixels will be added to the photos, and due to the not always accurate calculation of the colors for filling in the photo, there may be undetailed areas, graininess. As a result, quality drops.
So interpolation in the phone is a marketing ploy that is completely unnecessary. It can increase not only the resolution of the photo, but also the cost of the smartphone itself. Do not fall for the tricks of sellers and manufacturers.