It sounds like “laser speckle imaging” is the kind of thing you need to fund to experiment, But as [anfractuosity] Recent show, You can get some very impressive results with relatively simple hardware settings and some common open source software packages. In fact, you may now have all the components needed to achieve this goal in your own studio, just not knowing it.
Anyone who has played with a laser pointer is familiar with the flash effect observed when a beam of light shines on certain objects. That is laser speckle, which is produced by the microscopic changes in the texture of the reflected surface of the light beam and optical interference. Although this phenomenon prevents the laser beam from becoming an effective direct light source to a large extent, it can be used as a way to measure tiny disturbances in a seemingly flat surface.
In this demonstration, [anfractuosity] Combining a simple red laser pointer with a microscope’s 25X objective lens can produce a wider, lower intensity beam. When this diffused beam is projected onto the wall, the spot pattern produced by the surface texture can be clearly seen.what is no It is obvious to the naked eye that touching the wall with your hand will actually produce a change in the pattern of spots. However, if you shoot high resolution before and after shooting, you can run the image through OpenCV to highlight the difference and show ghostly handprints.
[anfractuosity] Then use the same technique before and after pressing certain buttons on the calculator. The final cleaned image not only clearly shows the numbers on the display, but also highlights the touched buttons. Seeing this example, it is not easy to think that this technology may have some evil applications. Can an attacker use laser speckle imaging to determine which buttons on the lock keyboard or alarm panel were pressed?
Fortunately, it sounds quite difficult to put such an attack into practice.On the one hand, the camera and laser need to be Exactly The location when shooting before and after is the same, which is almost impossible for covert operations. Second, as shown in the video below, the imprint tends to decay quickly. The shot must be shot within a few minutes of touching the keyboard, which makes it more difficult to draw the bar in the field.
It is not obvious what practical applications this technology might have in hackers and creative guest groups, so we would love to hear any ideas you might have. In any case, this is an impressive achievement and a great example of modern amateurs.