Hello and welcome! In this video, we will review the history of the evolution of of the principles of image acquisition, from the first photographs to the era of of digitization and image processing. Can you explain to us when the first attempts to acquire first attempts to acquire images? The principle of the camera, as we know it as we know it today, was already mastered by the Greeks and the Chinese 500 years before our era. This device, called by the Romans camera obscura, is today better known under the name of pinhole. It is based on a simple principle: an object is placed in front of a a black box with a hole in it, and an image of the this object will be projected on the bottom of the box. However, because of the path of the light rays the image in the pinhole is inverted. Nicéphore Niépce is the first one to really fix an image on a physical support with an exposure time estimated at several days, and a result... closer to abstract art than than a real photograph. We are in 1827. A few years later, Louis Daguerre joins forces with Nicéphore Niépce. In 1838, they realized the first photograph of a human being, on the human being, boulevard du temple in Paris. For this, they use more precise and simple fixing agents and simple to use, which allows to reduce the exposure time to 20 minutes. After this first success, their camera, the daguerreotype, becomes popular. It is a handy and accomplished device, which allows to make photographs very close to those very similar to those we know today. When the general public talks about photography today, it is about images that use the visible spectrum of light, that is the one represented by the colors of the rainbow and to which our eyes are sensitive. But something tells me that reality is more complex? Right! An image can of course be constructed from other other radiation or physical principles, in order to be able to observe other particularities of matter, such as X-rays. In 1895, the German physicist Wilhelm Röntgen discovered them and opened the field of possibilities by penetrating the interior of matter matter, and especially through the living. The first X-ray is none other than is none other than that of his wife's hand. The first X-ray scanner will be installed in a hospital in 1971. This technique is only made possible by the advent of computers, because the reconstruction in three dimensions requires important computing means. The medical world is a big user of user of imaging techniques. The principle of nuclear magnetic resonance is discovered in 1945. In everyday language, it is called MRI. The first obstetrical ultrasound machine appeared in 1950. Its principle is based on the sonar principle, developed for the needs of the two world wars and and the tracking of submarines. Another imaging technique, much less known to the general public of the general public, atomic force microscopy was developed in 1985. It allows to observe the structure at the atomic scale using the forces of repulsion and attraction between them, here in the case of chromosomes. Thanks to the progress of the technique, we are now able to obtain images able to obtain images of atoms or distant galaxies, from the infinitely small to the infinitely large. In all fields, from industry to everyday life we are invaded by images. We are now going to dwell on the way to acquire and how to acquire and transmit images. That's right, before computer digitization, how did we transmit to transmit photographs? In 1920, the system, nicknamed Bartlane in homage to its to its creators, allowed the transmission of the first digital image between the United States and Europe using the transatlantic cable. This transfer was made by transforming the image the image into a sequence of codes, which prefigures the computer structure of the coding then of the treatment of the images. Transmission techniques are improving rapidly rapidly: this image dating from 1929 is coded on 15 levels of gray: spatial sampling and quantization of information are born. Parallel to photography, television television is in its infancy. in the 1920s thanks to tube cameras. The first CCD sensor, which allows fast acquisition and simple data handling, is built in 1969. Today it is the most widely used type of digital sensor, because it is very cheap and easily mass-produced. As a result, we find them everywhere: in cell phones, high definition camera, gate intercom and even in cars. Since the 1950s, the digital revolution has been underway. CCD sensors, optical devices, electronics the means of storage and transmission, all have undergone extraordinary development. From MRI to Snapchat, the uses are different different, but the computer basics are the same. and mathematical basis for processing are the same. The countless images produced at each moment contain information. The field of image processing consists in implementing a series of mathematically defined transformations, defined mathematically and transcribed by computer, which allow to simplify and to isolate the present data, to extract the relevant information and to allow their analysis. In view of the amount of information to be processed, the key word in this the key word in this field is automation, in order to reduce human intervention as much as possible.
