Principle and characteristics of pinhole imaging

The principle of pinhole imaging is the linear propagation of light. Features: 1, the image is a real-life image. 2. The finished image is inverted and symmetrical to the original object. 3. The size ratio of the image is the same as that of the object. 4. The ratio of image size to object size is the distance from pinhole to imaging screen divided by the distance from pinhole to object. 5. The smaller the pinhole, the clearer the image, but the lower the brightness. 6. If the object is colored, the image is colored, and the colors of the image and the object are the same. 7. The clarity of the image is related to the size of the pinhole, but not to the shape of the pinhole.

When a wooden board with a small hole is blocked between a wall and an object, the reflection of the object will be formed on the wall. We call this phenomenon pinhole imaging. Moving the middle board back and forth will change the size of the image on the wall, which shows the nature of light propagating along a straight line.

Some cameras and camcorders use the principle of pinhole imaging-the lens is pinhole (mostly equipped with convex lens to ensure the imaging distance of light), the scene enters the darkroom through pinhole, and the image is left on the film by some special chemicals (such as silver halide) (digital cameras and camcorders store the image in the memory card through some photosensitive elements).

The conclusion of pinhole imaging experiment is that light travels in a straight line in the same homogeneous substance. When the image distance is constant, the closer the object distance, the larger the image and the brighter the brightness; The farther the object distance, the smaller the image and the darker the brightness. When the object distance is constant, the close-up image of the screen becomes smaller and brighter; The screen looks bigger and darker. When the position of the object, hole and screen remains unchanged, imaging is the premise, and the image becomes brighter when the hole is relatively large.