Photogrammetric processing (Image Processing)

The technical basis for the formation of photogrammetry was the invention of photography by the Frenchman Daggerome in 1839. In 1851-1859, Frenchman Lassedat developed a graphic version of photogrammetric drawing of plans of constructions based on their ground photographs. Creation of aeronautics provided an opportunity to move from ground engineering photography to aerial photography. In 1858 Frenchman Nadar took the first photographs from a balloon. This was an important step in the development of photogrammetry - the aerial photo was closer to a terrain plan in its geometry. The first aerial photographs from a balloon in Russia were taken on May 18, 1886. A.M. Kovanko. St. Petersburg was photographed by V.N. Sreznevsky's aerial camera from altitudes of 800, 1200 and 1350 meters. In 1910 the pilot Gelgar received the first photographs from an airplane in Russia. At first, aerial photography was used mainly for military reconnaissance purposes. The emergence and development of electronic computer technology significantly influenced the technology of photogrammetric image processing. Methods of spatial analytical phototriangulation were developed and widely used. There comes a period of creation and use of analytical stereophotogrammetric devices. Transformational functions in them were performed by computers. A device of this class - stereoanagraph - was created in our country. This period (60s - 80s of the XX century) was a transition to the stage of digital photogrammetry. Digital image processing technologies are currently the main technologies for cartographic and engineering works.

The main application of photogrammetry is considered to be the creation of topographic maps based on photographs taken with specialized cameras. Cameras used to capture images from ground points are called photogrammetric theodolites, and the process of capturing images is referred to as photogrammetric. Cameras utilized in the aerial surveying process from aircraft, helicopters, or unmanned aerial vehicles are simply called aerial cameras, and the corresponding surveying is referred to as aerial photography.

Application of Photogrammetry in Film and Gaming Industry

In recent years, photogrammetry has found its place in the modern film industry, and the 3D technology for generating volumetric images in films has gained special popularity among young audiences. The art of animation has always captivated audiences with its mesmerizing end results in the form of popular animated films.

• Combined Method of Cartography: The main difference between the combined method and the stereotopographic method is that in the combined method, aerial photography is used only for creating the contour part of the maps.
• Stereotopographic Method of Cartography: With the stereotopographic method of cartography, all processes of image processing are carried out on universal photogrammetric instruments (UP, AUP, stereoplotters).

Currently, the coordinates X_S Y_S Z_S can be determined using GPS, and angular elements can be determined using inertial systems. However, since these systems can be expensive and may experience malfunctions, they are not always used. Therefore, the photogrammetric method of determining the elements of exterior orientation is employed - based on control points.

Control points are points whose coordinates are determined on the ground, typically in the Gauss geodetic coordinate system, and they are identified on the aerial imagery. By measuring the coordinates of the control points on the operator, a direct or inverse relationship between the points on the iimagery and the corresponding points on the ground can be established.

Photogrammetric processing of the survey is preceded by preparatory work, which includes the following steps:

• Preliminary processes:

a) Collecting, studying, and evaluating the initial shooting and cartographic materials, materials from field topographic-geodetic surveys;
b) Work technical designing of the operator processing processes;
c) Preparation of necessary materials and source data;
d) Preparation of technical equipment;
e) Preparation of editorial instructions;
f) Training of engineering-technical personnel and operators;

• The preparatory processes are further detailed as follows:

• Collecting, studying, and evaluating the initial shooting and cartographic materials, materials from field topographic-geodetic surveys;
• Work technical designing of the photograph processing processes;
• Preparation of necessary materials and source data;
• Preparation of technical equipment;
• Preparation of editorial instructions (Editorial instructions are developed based on the technical project using all the primary and additional materials and the results of their analysis. Special attention is paid to poorly recognizable features of the terrain/surface, as well as features that cannot be directly identified from the main aerial photographs. For such features, sources are listed from which they can be displayed on the original photographs.);
• Training of specialists for the execution of the work.

Photogrammetry uses all modern surveying tools, including professional digital cameras, television surveying systems, scanner laser systems, radar systems and others. Photogrammetric cameral processing consists in measuring images on special optical and mechanical devices (stereo comparators), allowing to obtain plan and height (spatial) position of objects on images, to observe them in four-dimensional coordinate system with changes in time and further compilation of topographic plans and maps.

1. High measurement accuracy;
2. High degree of automation in the measurement process, leading to the objectivity of their results;
3. High productivity (as measurements are performed on images of objects rather than the objects themselves);
4. Possibility of remote measurements in situations where human presence on the object is unsafe.

Photogrammetric processing involves extracting geometric information from images captured by aerial or terrestrial cameras. It contributes to mapping and surveying by enabling the creation of accurate and detailed maps, 3D models, and terrain information through the analysis of overlapping images.

Ground control points are reference points on the Earth's surface with known coordinates. In photogrammetric processing, these points are used to georeference and scale images accurately. The inclusion of ground control points ensures the reliability and precision of the derived spatial information.

Stereo imagery involves the use of overlapping images captured from slightly different perspectives. In photogrammetric processing, stereo pairs are used to create a three-dimensional effect, allowing for accurate depth perception. This is essential for creating detailed 3D models of the terrain or objects captured in the images.

Digital Surface Models (DSMs) represent the Earth's surface, including both natural features and built structures, while Digital Terrain Models (DTMs) focus on the bare ground without considering surface features. In photogrammetric processing, these models are used for applications such as urban planning, flood modeling, and landform analysis.

Advancements in sensor technology, unmanned aerial vehicles (UAVs), and computational capabilities have significantly influenced the efficiency and accuracy of photogrammetric processing. High-resolution cameras, GPS, and advanced algorithms enable faster data acquisition, processing, and the generation of detailed and precise spatial information from images.