Pinhole Camera

The pinhole camera is the first generation camera model that apply the simple principle and have no practical. You can easily understand and make it by yourself.

Principle of Pinhole Camera

1 Light enters through a closed box with a small hole

The small hole is opened on the front side of the camera through which light enters, the smaller light that runs through the hole is forming to be an inverted image on the opposite scene that’s called image plane.

2 Perspective transformation

The optical axis, which the distance between object and the camera’s hole, runs through the pinhole perpendicular to the image plane. By matching similar triangles, the height of the projection ‘y’ is determined by two parameters, the focal length ‘f’ and the distance between object and the camera’s hole ‘Z’. By the way the width of the projection ‘x’ also uses the same principle.

According to the principle, the short focal length results in a small image and a large viewing angle. In contrast, increasing the focal length results in a larger image and a smaller viewing angle.

The projected image is flipped in the horizontal and vertical directions, it is rotated by 180◦ due to the perspective transformation with similar triangles be used.

How to make Pinhole Camera

There are many ways to make the Pinhole camera. This video clip link below shows how to make the Pinhole camera as easy as you can do it.

click me!!

Results

These pictures illustrate images that were captured by the pinhole camera according to the video clip above. The camera has 3.5 centimeter focal length, the distance from the object is 1 meter, and the exposed times are 1, 3, 5, 10, 20 seconds respectively.

These pictures below are acquired by the pinhole camera above which has the focal length with 3.5 centimeter. It was exposed the light runs through in the small hole with 5 seconds and the distance from the object is 1 meter.