Image Assisted Surveying by Leica Geosystems
 
 

Image Assisted Surveying by Leica Geosystems ~ October 2010

Leica Geosystems introduced Image Assisted Surveying on their Total Stations with the introduction of the Leica Viva imaging Total Stations in October 2010 and this product was launched in the United Kingdom and Ireland as part of GeoWorld 10.

The Leica Viva imaging Total Stations are fitted with a 5 Mpixel CMOS sensor, which with a 21mm lens provides a field of view of 15.5 by 11.7.  The sensor has a 20 Hz refresh rate providing a smooth visual presentation.

The on-board camera can be used to record images and relate them to one or more measured points, and can be used to control the Instrument.  The captured images can be annotated by the user and the imaging software can also be used to make a "screen capture" of any screen displayed, which can also be annotated as required.  The annotation functionality can also be used to sketch to a blank screen providing maximum versatility in the field.  There is no longer any need for the Surveyor or Engineer to take a notebook or camera to the field.

 
   

Control the Leica Viva imaging Total Stations from the image:

Tap - tap the screen to tell the Instrument where to turn to

Turn - The Instrument turns to the tapped location

Measure - Press Meas and the Instrument locks onto the prism with the ATR (Automatic Target Recognition) and measures

The image can be stored automatically to every measured point or assigned to any point in the database.

   

Capture an image with or without the cross hairs and add information:

Capture - record any image displayed by the Instrument

Sketch - Add information to the screenshot through sketching with any colour, line style and line width

Link - Link the image to any object of interest (point, line or area)

The image can be assigned to any point in the database.

   

Capture any data displayed to the screen:

Capture - Capture a screenshot of any panel in SmartWorx

Sketch - Add information to the screenshot through sketching with any colour, line style and line width

Link - Link the image to any object of interest (point, line or area)

The image can be assigned to any point in the database.

 

Image Assisted Surveying greatly enhances the functionality, ease of use and productivity of the on-board applications for the Leica Viva Instruments.  The animation shows the Instrument running the Grid Scan application.  The irregular polygon for the area to be measured is defined by using the Tap and Turn functions on the displayed image.  The Instrument is measuring a regular grid on the defined plane and the operator has the option to record the image for each measured point.  The application can also measure all the points where the defined grid meets the boundary of the area being measured and the displayed image shows these.  Control of the Instrument is through the full VGA touch screen.

These features are particular useful when using Grid Scan to measure subjects such as stock plies for immediate volume calculations

 
   

One of the major advantages of Image Assisted Surveying is that it combines the previously separate operations of one person (robotic) surveying and reflectorless measurement.  The use of reflectorless measurement requires an operator at the Instrument to position the cross hairs on the point of interest, whist the use of the Instrument in one person mode requires the operator to be at the detail pole.  With Image Assisted Surveying it is now possible for the operator to be at the detail pole and turn and aim the Instrument to a point for reflectorless measurement.  Consider the scenario where the operator is at the detail pole some distance from the Instrument (say 100m) and wishes to measure an inaccessible point.  e.g. the operator is on the left side of the river in the image and wishes to record the position of the tree.  The operator no longer needs to return to the Instrument to make the measurement but simply turns the Instrument by tapping on the image then measures to the point of interest.

Combined Reflectorless and One Person Surveying

History

Wild P30 Photo TheodolliteWild P32 Camera on a Wild T2 TheodoliteThe connection between imaging and measurement in the Leica Wild Kern organisation goes back nine decades.  Heinrich Wild created the Wild P30 at the same time has he created the legendry Wild T2 1" theodolite.  More than half a century later, in the early 1970s, Wild Heerbrugg launched the Wild P32 camera which was mounted on top of a theodolite, such as a Wild T2 or Wild T1.  These Instruments provided the user with images that could, in today's terms, be geo -referenced.  They had location and orientation and this information could be used to extract information for measurement purposes.  Data extraction could be by using either a conventional Photogrammetric procedure or by methods such as Photographic Intersection.  These cameras used film or glass plates to record the images and were constructed to have virtually no lens distortion, but modern digital cameras could be used in the same way with the lens distortions corrected by computer software.

Photo-Theodolite without TelescopePhoto-Theodolite without TelescopeSome two decades later, in the 1990s, Leica Geosystems in connection with Generics, based in Cambridge, England, developed a theodolite with the conventional telescope replaced by a digital camera.  Control and aiming of this Instrument was via the image displayed to the screen.  The prototype, shown here, was produced, but the project was not pursued, presumably because of the difficulty of including a co-axial EDM.  However, the potential of Image Assisted Surveying was well demonstrated.  As with the Wild P30 and Wild P32, this device provided an image with a known location and orientation, which was suitable for data extraction using Photogrammetry or Photographic Intersection.

Leica Geosystems have waited for the relevant technologies to mature sufficiently before launching Image Assisted Surveying.  Products that are on the "Slope of Enlightenment" or "Plateau of Productivity" on the Gartner Hype Cycle can be relied on and trusted.  The wide angle digital camera with its 5 Mpixel sensor and the full VGA screen provide the required resolution and precision for Image Assisted Surveying.

 
 

Photogrammetry and Photographic Intersection

The prime objective of Leica Geosystems introducing imaging with the Leica Viva Total Stations is to provide the user with Image Assisted Surveying to increase productivity in the field and ease of use of the Instrument.  However, there is clearly the potential to use this functionality for Photogrammetry and Photographic Intersection.

The internal wide angle camera is calibrated and the values can be out be output with the measured data using the Format File options available in Leica Geo Office (LGO).  The Inner Orientation values include the Principal Point (pixel co-ordinates) and Focal Length and the Exterior Orientation values are calculated for each captured image.  The Exterior Orientation values include the co-ordinates of the Projection Centre and the direction of the Principal Ray as Horizontal and Vertical Angles.  Each image therefore has location and orientation and is available for Photogrammetric interpretation.

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