What is Close Range Photogrammetry? Close Range Photogrammetry Applications

What is Close Range Photogrammetry?

Close Range Photogrammetry is the process of using photography and specialized software to measure objects and distances between objects.

This technology is used for a variety of purposes, including mapping, surveying, and forensics.

Close range photogrammetry can be used to create three-dimensional models of objects, which can be used for a variety of purposes, including engineering and design.

The term “photogrammetry” is derived from two Greek words: “photo” (light) and “gramma” (line). Therefore, it literally means “light-line measurement”. Photogrammetry is also referred to as “measuring from photographs”

Close Range Photogrammetry is a process that uses photography and geometric calculations to create an accurate 3-dimensional model of an object or environment.

A photogrammetric capture typically includes a set of overlapping photographs, taken from various angles, with each photograph having matching features such as color, contrast and texture.

These photographs are then converted into a 3-dimensional model by triangulating the relative positions of the photos and extracting depth information from them.

Photogrammetry is commonly used for creating scale models, aerial orthographic views, architectural drawings, real-estate maps, and textual archaeological records.

Close Range Photogrammetry History

Photogrammetry is a process that started in the 19th century. The first photogrammetric image that was made in a real-world setting was created by French Engineer, J. A. Generali. Generali took photos of salt pans for the purpose of creating scale models to aid in the construction of canals.

In the 1920s, photogrammetry was the most advanced field of all applied sciences. The tool that aided in the methods of photogrammetry were called “patent cameras”.

These were large cameras that were mounted onto a tripod and had a device that would move the camera in accordance with two separate measuring rods. The device that moved the camera allowed for measurements to be taken from various angles, in a three-dimensional manner.

Photogrammetry has been used throughout history for measuring the sizes of objects, faces and even people. During the early 1900s, photogrammetry was used by archaeologists to create drawings and records of ancient artifacts.

Photogrammetric information is still being used today for the creation of architectural drawings and printed maps that aid in real-estate transactions.

Close Range Photogrammetry Principles

There are a set of principles that are used to create photogrammetric models from photographs.

The principle “Photogrammetry Triangle”.

This principle comprises three essential points. These points were taken by using the same camera and tripod system that was used in capturing the photos.

The center point is referred to as the “base point”. This base point represents the origins, or barycenter of both photographs. The base point is usually located at the midpoint between two photographs.

A second point, the “ground control point”, is located in the background of the photograph. This point is used as a reference for measuring the depth and size of objects within the photograph.

The third point, also known as the “roof control point”, is usually placed on top of large items in order to aid in measuring their depth, such as trees.

The roof control point is located on the roof of the structure, or any other obstacle that can be used as a reference to determine the size and depth of objects in the image.

The “Principle of Correspondence”

This principle states that the distance from the camera to an object is proportional to the height of that object’s projection on the picture surface.

The “Principle of Parallax”

states that objects are usually photographed in such a way that the distance between the camera and objects remains constant within any given image.

Close Range Photogrammetry Process

The process of creating photogrammetric models involves a set of procedures.

1. The first step is to create a three-dimensional wireframe model using a CAD program.
2. The next step is to assign the photos to specific points on that model. These points are referred to as “ground control points”.

For each image, the computer will search through the data of its matching “ground control point”, in order to identify the correct matching location on the model.

3. The computer will then extract the data from the “background” of each image, and alter the model surface according to that data.
4. The final step is to adjust the dimensions of the model surface so that it matches with features in the photographs. It is important to note that just because a feature exists in one photograph, does not mean that it should be included on any given model.

Close Range Photogrammetry Applications

To date, Close-Range Photogrammetry has been used in a wide variety of mediums.

Three of the most popular applications include:

Scale models

Scale models are usually in the form of a three-dimensional printout or a rendered model. These models are most commonly used to depict realistic proportions, while providing the viewer with enough detail to convey the entire scope of a project.

Cranes running from the ground to the top of buildings will have scale models of their surroundings attached to them in order for them to be able to maintain their balance.

The process is commonly used for creating scale models, such as dimensional topographic maps used for land management. The process also uses satellite imagery, aerial photos and geo-referenced images for various purposes.

Aerial orthographic views

Aerial orthographic views are photographs that contain no depth information. Aerial orthographic views are created for the purpose of depicting a building or structure from various angles and heights.

These views are commonly used for creating architectural drawings and floor plans.

Architectural drawings

Architectural drawings are usually in the form of a two-dimensional printout or rendered model. Architectural drawings are used for the purposes of drawing architectural structures and plans.

These drawings are used to aid in the creation of a scale model, or to provide interior design professionals with accurate measurements.

Research purposes

Close Range Photogrammetry has been used for decades. It has the ability to measure specific features found in a variety of subjects.

Photogrammetry is used for measuring the sizes and shapes of archaeological objects, such as potsherds or fragments of walls.

Archaeologists use photogrammetry to create drawings and records of ancient artifacts. These drawings are called photogrammetric surveys and archaeological records.

Archaeologists use photogrammetry to measure, with great accuracy, the sizes of temple and tomb walls. The measurements are taken by scanning the structure with a high-resolution camera from all angles.

This can be done with a handheld unit or one mounted on an aerial vehicle. The measurements are then used to create models and print maps of the sites being investigated.

Archaeologists are able to use photogrammetry to measure the angles of walls of tombs and temples. This is done with a handheld unit or one mounted on an aerial vehicle. The measurements are then used to create models and print maps of the sites being investigated.

Archaeologists are able to use photogrammetry to measure temples, tombs, and other structures from many different angles.

The measurements taken in this process are normally taken from photographs taken from low altitude planes that fly over these sites.

The measurements are used to create digital maps that can easily be displayed on computer screens for future reference.

Archaeologists use photogrammetry to measure the heights of walls from specific angles using a handheld unit.

This is done with a handheld unit or one mounted on an aerial vehicle. The measurements are then used to create models and print maps of the sites being investigated.

The use of photogrammetry in archaeology is due to the size, shape and spread of archaeological sites, which can vary drastically from site to site.

Close Range Photogrammetry Techniques

Close Range Photogrammetry can be accomplished using a variety of techniques, but the following are the most common.

Tracking/Terrestrial

A camera is mounted on an automatic tracking device, which can be attached to vehicles or simply carried by hand. This type of photogrammetry is used for mapping and terrain modeling.

Satellite

Satellite-based photogrammetry involves using satellites with high-resolution cameras to take multiple photographs of a site from above the atmosphere. The photographs are then digitally combined to produce a digital map image.

Unmanned Aerial Vehicle (UAV)

A UAV, commonly referred to as a drone, is an unmanned aerial vehicle that is remotely controlled by a pilot. These vehicles can be used to capture photographs and digital elevation model data of sites.

Handheld

Handheld photogrammetry involves using a digital camera or camcorder to take multiple photographs at different angles of an object or site. The photos are then combined into a digital map image.

Digital Photography

Digital photography is a type of photography where the output of each process involves files that are in digital format.

Digital photography is used to take photographs from various angles and to combine these photographs into an accurate digital map.

Various cameras are available on the market today that can be used in Close-Range Photogrammetry applications. Some cameras may be used singularly and do not involve any other equipment, while other equipment combinations may be required for accurate measurement.

Aerial

Photogrammetry using aerial photography can be accomplished using either a photogrammetric camera mounted on an aircraft or a fixed-wing aircraft.

This type of photogrammetry is used for creating images of sites from above the atmosphere.

This type of photogrammetry is useful for creating high-resolution maps and captured images that can be used in computer graphic software, as well as in the creation of renderings and models from the photograph taken from above.

Close Range Photogrammetry Collection Methods

There are a variety of methods used to collect photos and data for Close Range Photogrammetry applications.

There are five main methods used to collect photos and data.

1. Multiple-Photographs -Photographs taken at different angles and distances from an object can be combined together to create a complete view of the object. These photographs are typically taken from the same camera with different lenses, but multiple cameras can be used to take photographs in various positions of an object.
2. Angle- This photogrammetry collection method involves taking pictures of an object from a specific angle while the camera remains in a fixed position. A variety of cameras, lenses, and accessories can be used at once to take such photographs.
3. Jump/Scan-Photographs are taken by moving the camera rapidly during the exposure of the photo. The resulting photos appear as though they were taken on a single line but actually contain information from many different points. A variety of cameras, lenses, and accessories can be used simultaneously.
4. Satellite-Satellite-based photogrammetry involves using satellites with high-resolution cameras to take multiple photographs of a site from above the atmosphere. The photographs are then digitally combined to produce a digital map image.
5. Hybrid Methods-Photographs taken by either multiple cameras or by one camera while being moved quickly at different angles can be used in Close-Range Photogrammetry applications.

Close Range Photogrammetry Benefits

The benefits include:

1. High-Quality Views: Photogrammetry can be used to create high-resolution maps and images of sites that are difficult or impossible to view without the use of other methods.
2. Detailed Information: All of the information that is found on an object is taken into account when creating a digital map or photograph while using Photogrammetry. This includes measurements from many different angles, measurements from all directions, as well as dimensions and shapes of the object being measured.
3. Aerial Views: Aerial photogrammetry captures a high-resolution image of a site from above the atmosphere. This can be done either by using an aircraft, which flies over the area being photographed, or by an aerial vehicle which is remotely controlled to take photographs from above.
4. Accuracy: Close Range Photogrammetry provides a more accurate map when compared to other methods due to the fact that each and every measurement is taken into account throughout the process.
5. Affordable: Close Range Photogrammetry is generally more affordable than other methods of measuring a site. The equipment needed is portable and can be used to measure many different sites at once.
6. Time-Saving: Close Range Photogrammetry allows for the collection of information in a much faster time period than other methods because each and every measurement is taken into account throughout the process.

FAQs

 What is the easiest photogrammetry software to use?

This depends on the types of software you are able to use. The software can range from simple to complex, but these basic features are found in most photogrammetry software:

Leveling-Leveling involves using a variety of tools and methods so that the camera is properly oriented with each photograph. (This is commonly referred to as orientation.)

Projection-Projection involves taking measurements from one or multiple photographs in order to create a 3D model.

Combining -Combining involves combining the measurements from several photographs taken from different angles and distances in order to create a high-resolution 3D model.

What is the best way to understand Close Range photogrammetry?

The easiest way to understand Close Range Photogrammetry is to familiarize yourself with the basic principles of photogrammetry.

 Do I have to have a special camera for Close Range Photogrammetry?

No, any type of digital camera can be used in this method. However, there are some cameras which are better suited for taking photographs at various distances and angles.

Can Close Range Photogrammetry be used by architects?

Yes, the method is useful for creating architectural drawings, but the photographs can also be used in other applications such as in combination with computer-generated models for engineering and CAD work.

Can Close Range Photogrammetry be used by engineers?

Yes, a high-resolution 3D model can be created from digital photographs which are taken in close range. This model can then be used to better visualize certain features and locations on a site prior to construction of a building or roadway.

What is the best Camera for Close Range Photogrammetry?

Any digital camera can be used for Close Range Photogrammetry. The type of camera used will depend on the use of the photographs, but a high-end camera is recommended.

You may also wish to consider using a camera which can help to reduce the blurriness caused by movement between exposures.

How much does it cost to do Close Range Photogrammetry?

It depends on the equipment needed and what your intended use is for the Close-Range Photogrammetry application.

The equipment needed can be fairly inexpensive, but the amount of time invested in the project will affect the overall costs.

What are the disadvantages of Close-Range Photogrammetry?

It is not as accurate as other photogrammetry methods. This is due to the fact that Close Range Photogrammetry only takes measurements from a single view which means there are fewer measurements that can be taken into account when creating the digital map or photograph.

What is the difference between Close Range Photogrammetry and Aerial Photogrammetry?

Aerial photogrammetry involves taking high-resolution photographs of the area being mapped or photographed from above the atmosphere.

Close Range Photogrammetry involves taking measurements from a single view while at close range to the site or object in question. A hybrid can also be used in which aerial photography is taken and then combined with photographs taken closer to the site.

How accurate is Photogrammetry when compared to other Photogrammetry methods or even regular Surveying?

In general, it is very accurate in terms of being able to accurately recreate a site or object’s shape and measurements.

However, a limitation of the Close-Range Photogrammetry method is that it cannot be used to measure areas that are at a distance from the camera.

The information can only be taken from a single viewpoint at close range.

Are there any similarities between Close Range Photogrammetry and Photogrammetry at a distance?

The methods are quite similar in that they involve taking measurements from one or multiple photographs. But their methods of achieving the measurements differ

In Photogrammetry at a distance, the photographs must be taken at even greater distances in order to account for each and every measurement. In Close Range Photogrammetry, only one photograph is taken which provides more accurate measurements.

How do you take Close Range Photogrammetry?

The main concept involves setting up a camera on a tripod and measuring distances from each photograph.

First, the camera needs to be properly leveled and then turned in the direction of the object or site which is intended to be taken apart. After this, measurements are taken from each image so that an accurate 3D model can be created.

What is the difference between Close Range Photogrammetry and Near Field Photogrammetry?

Close Range Photogrammetry uses photographs taken at close range to the site or object in question. Near Field Photogrammetry, on the other hand, involves taking photographs at even greater distances from the site.

A hybrid can also be used in which aerial photography is taken and then combined with photographs taken closer to the site.