The real image can be zoomed in or zoomed out, right, please explain, thank you

Yes, the real image can be presented on the light screen, it is formed by the convergence of actual light, can make the negative light, so it is called the real image.

To put it simply, as long as the image that can be accepted on the light screen is a real image, regardless of size and direction (junior high school physics.

Real image: The light emitted by an object is reflected or refracted by an optical system (such as a concave mirror, convex lens, lens group), and then reconverges to create a picture similar to the original (magnified or reduced) (so it can be magnified or reduced).

The real image can be presented on the light screen, it is formed by the convergence of actual light, which can make the negative sensitive to light, so it is called a real image.

In the case of convex lenses, the light source is outside the primary focus to produce a real image.

The image of the small hole is also a real image.

The real image can be presented (presented) with a light screen, and it is an image formed by real light.

Right. Generally, our common real images are small hole imaging and convex lens imaging.

The size of the image is determined by the distance between the screen and the hole, and the farther the distance, the larger the image, so the hole can be a reduced or enlarged image.

In the case of a convex lens to make a real image, the object is placed in the convex lens at a focal length of one time.

When an object is between the double and double focal lengths of a convex lens, the object forms a magnified real image on the other side of the lens, as is the case with projectors and cinema projectors.

This is the case when an object is outside the double focal length of a convex lens and becomes a reduced image on the other side of the lens, as is the case with camera applications.

According to the four cases of convex lens imaging:

u 2f, an inverted, reduced real image U=2F on the other side of the convex lens, an inverted, equal-sized real image 2f u f on the other side of the convex lens, an inverted, magnified real image u f on the other side of the convex lens, and an upright, magnified virtual image on the same side of the object

Answer: It can be seen from the imaging law of the convex lens that when U 2F, it becomes an inverted and reduced real image, when U=2F, it becomes an inverted and equal-sized real image, and 2F U F becomes an inverted and magnified real image; Therefore, the real image made by the convex lens may be magnified or reduced, which is correct.

To create a clear magnified real image on the screen, the object should be placed between the double focal length and the double focal length, i.e. 2f>u>f.

Three cases and applications of convex lens imaging:

U 2F, a handstand, zoomed out real image, is used in cameras and camcorders.

2f u f, into an inverted, magnified real image, used in slide projectors and Shen Song Bureau projectors.

u f, into an upright, magnified virtual image.

Apply to a magnifying glass.

The imaging law of convex lenses.

Convex lens imaging rules.

It is a law of optics. In optics, the image that is formed by the convergence of actual light rays and can be presented on the optical screen is called a real image; The image that is formed by the convergence of the extension line of the reverse width of the light rays and cannot be displayed on the light screen is called a virtual image.

When talking about the difference between real and virtual images, it is often mentioned that "real images are upside down, while virtual images are upright." "If it's a thick meniscus concave lens.

The situation will be more complicated. When the thickness is large enough, it is equivalent to the Galilean telescope.

When the thickness is larger, it also acts as a positive lens.

The convex lens is refractive imaging, and the resulting image can be an inverted or reduced real image; Inverted, equal-sized real images; inverted, magnified real images; Upright, magnified virtual image. It has a converging effect on light. The concave lens is a refractive image, which can only be a virtual image of the cherry blossom standing quietly and shrinking.

It has a divergent effect on light.

Assuming that the original image is m*n and the size of the reduced image is m*n, you need to divide the image into disjoint pieces of (m*n) (m*n) size, and calculate the average value of the small pieces, which is used as the pixel value corresponding to the reduced image.

As shown in the figure below:

Let's shrink a 16*16 image into a 4*4 image:

The size of such disjointed pieces is 16

Then calculate the average value within the small block:

The first two parameters are the input and output images, respectively. dsize indicates the size of the output image.

Upsampling principle: Image upscaling almost all kernels are excavated by using the interpolation method, that is, on the basis of the original image pixels, a suitable interpolation algorithm is used to insert new elements between pixels.

Interpolation algorithm classification:

The classification of interpolation algorithms is generally divided into three categories: traditional interpolation, edge-based interpolation and region-based interpolation.

Firstly, the original low-resolution image is divided into different regions, then the interpolation points are mapped to the low-resolution images to determine the region to which they belong, and finally the interpolation formulas of different missing tanks are designed according to the neighborhood of the interpolation points to calculate the values of the interpolation points.

a. Dew drops are equivalent to convex lenses, and the leaves are magnified by dew drops like convex lens imaging, which is a refraction phenomenon of light, so A does not conform to the topic;

b. The reflection of trees in water is a plane mirror image, which is a reflection phenomenon of light, so B does not conform to the topic;

c. The white light passes through the prism to form an auspicious color light band, and the dust bends orange which is caused by the refraction of light through the prism, so C does not conform to the topic;

d. Hand shadow is a dark area formed behind the object when light encounters an opaque object in the process of propagating along a straight line, so D is in line with the theme

Therefore, choose D

The relationship between object distance (u) and focal length (f).

1 The projector is made according to the principle of convex lens into magnifying the real image, when f

Answer: The reduced image of the reduced image is relative to the object, for example, in one of the imaging laws of convex lens and its application, U 2F, becomes an inverted reduced real image, and the inverted reduced real image is relative to the object; For example, when the convex lens becomes a real image, the object is far away and the image is close, and the image becomes smaller, so the meaning of the reduced image and the image become smaller are not the same