Examination 28.9.1998

1. The alternative ways of performing 3-D measurements.
2. The accuracy evaluation of photogrammetric measurements.
3. The calibration of a photogrammetric camera.
4. Photogrammetric measuring of object motion.
5. The alternative ways of measuring 2-D image coordinates of points in case of on-line applications.

Examination 18.5.1998

1. The design scheme of a photogrammetric system can be classified into four stages. The FOD or the "First Order Design" stage is dealing with the problem of network configuration. What are the parameters which are used for changing the network configuration during the FOD stage? What are the tools which are used for comparing the different network configurations with each other?
2. The size of the image to be used for the measurements is 512 x 512 pixels. The expected accuracy of the image measurements described as a standard error of one observation is S(x,y) = 0.05 pixels. The size of the object volume where the measurements are made is 2 m. In case of these data, how would you estimate the accuracy of the 3-D measurements in the object space.
3. The geometric distortions of video images.
4. The video cameras are used e.g. for ‘on-line’ applications. By using one application example, describe the characteristic features of such a photogrammetric ‘on-line’ control station, as far as it regards the building, calibration and operation of the station.
5. Consider one of measuring cases or examples described in the given publication, and classify it according to following aspects
• object's action
• measuring task
• measuring dimensions
• object size
• measuring accuracy
• measuring principle
• number of measured points
• recording
• processing.
Describe the example shortly, e.g. using some keywords and specific data.

• 1: The FOD is considering for configuration of an optimal network geometry for a given measurement problem. The tool for the purpose is the configuration matrix A, which can be designed for a given weight matrix P to yield a cofactor matrix Q, that meets the specified criteria. The criteria would be the shape and size of the error ellipsoids.
• 4: In 'on-line' applications, compared to 'off-line' applications, some basic characteristics are typical, like:
• the station has to be built from several permanently mounted cameras, which often are also synchronized to each other
• the calibration adjustment, usually a bundle block adjustment, cannot include any block-invariant parameters while solving the interior orientations of the cameras
• the calibration is done once during the building of the station, and controlled and updated during the operation of the station,
• the measurements are primarily made
• for controlling the orientation of the object, or
• for controlling the deformation of the object, where the deformation is considered to be
• the temporal change in geometry, like dynamic deformation, or
• the altered form in geometry, like the deviation between "as built" and "as designed" geometries,
and therefore, instead of the full object geometry, only a limited number of points are to be measured at a time
• the operation is usually based on space intersections, as the calibration is supposed to be controlled continuously.

Examination 10.3.1998

1. The design scheme of a photogrammetric system can be classified into four stages. The FOD or the "First Order Design" stage is dealing with the problem of network configuration. What are the parameters which are used for changing the network configuration during the FOD stage? What are the tools which are used for comparing the different network configurations with each other?
2. Within each photogrammetric measuring task different kind of observations can be used for controlling the 3-D reconstruction procedure. What is the primary aim of using different kind of observations? What kind of observations would you consider as useful and with which priorities?
3. The set-up calibration of a photogrammetric station.
4. In some cases the DLT or the "Direct Linear Transformation" would be more suitable for solving the photogrammetric reconstruction task than the bundle based approach. In which situations would you prefer the use of DLT? In which situations the DLT approach cannot be used at all?
5. Consider one of measuring cases or examples described in the given publication, and classify it according to following aspects
• object's action
• measuring task
• measuring dimensions
• object size
• measuring accuracy
• measuring principle
• number of measured points
• recording
• processing.
Describe the example shortly, e.g. using some keywords and specific data.

Examination 21.10.1997

1. Instead of bundles the analytical formulation of the photogrammetric coordinate transformation can be based on projective equations. What are the projective equations? Compare these two alternatives with each other, and especially as it regards their practical application.
2. Laboratory calibration of video cameras.
3. Within real-time photogrammetric stations the object points are measured or located in the images generally using two-dimensional search approaches. In which way the observation and recording of the two-dimensional image coordinates is practically performed? Which is the base for the fact, that the precision of the image coordinates may be even 20 to 40 times better than the original pixel resolution?
4. The client calls you and is asking for a three-dimensional surface model of a building. Before you are ready to make any proposals for a potential solution you will ask for some further details about the measuring problem. After first five questions you propose the recording to be done using still-video cameras. What were the possible five questions and respective answers?
5. Within each photogrammetric measuring task different kind of observations can be used for controlling the 3-D reconstruction procedure. What is the primary aim of using different kind of observations? What kind of observations would you consider as useful and with which priorities?

Examination 2.9.1997

1. Consider one of measuring cases or examples described in the given publication, and classify it according to following aspects
• object's action
• measuring task
• measuring dimensions
• object size
• measuring accuracy
• measuring principle
• number of measured points
• recording
• processing.
2. What do we mean with the criteria or concepts like accuracy and precision while designing photogrammetric networks? How would you determine the term called "limiting error propagation"?
3. The calibration of the camera optics suitable for photogrammetric recording.
4. The conceptual procedure in producing a photorealistic surface model based on videography.
5. 3-D video digitizing using a laser profilometer.

1. -
2. -
3. One should distinguish between the calibration of camera optics and the calibration of a camera.
4. For example the following stages should be clarified:
• Arranging necessary control data on-site
• Recording of images
• Block triangulation
• Recording of the geometric 3-D model
• Recording of the texture maps
5. -

Examination 11.3.1997

1. Consider one of measuring cases or examples described in the given publication, and classify it according to following aspects
• object's action
• measuring task
• measuring dimensions
• object size
• measuring accuracy
• measuring principle
• number of measured points
• recording
• processing.
2. The size of the image to be used for the measurements is 512 x 512 pixels. The expected accuracy of the image measurements described as a standard error of one observation is S(x,y) = 0.05 pixels. The size of the object to be mesured is 2 m. How would you arrange the image acquisition in case the standard error of 3-D object coordinate measurements should be better than 0.05 mm.
3. The alternative procedures for the calibration of a real-time photogrammetric station.
4. The geometric distortions of video images.
5. What do you understand with a) on-line and b) off-line measuring applications? Compare these two measuring types to each other as it regards the operative specifications and practical realizations.

Examination 4.2.1997

1. The alternative ways of performing 3-D measurements.
2. The accuracy evaluation of photogrammetric measurements.
3. The digitizing of video images.
4. The calibration of a videoprofilometer.
5. An example of on-line measuring applications.

Examination 22.10.1996

1. Instead of the bundle model for photogrammetric perspective equations can be described using the projective transformations as well. The projective transformations are especially beneficial in case where the interior orientation of the camera is unknown. Using the projective equations for relative orientation the stereo model will be deformed. In hich way is it deformed? How would it be rectified?
2. The different uses of a reseau-grd in photogrammetric measuring tasks.
3. The size of the image to be used for the measurements is 512 x 512 pixels. The expected accuracy of the image measurements described as a standard error of one observation is S(x,y) = 0.05 pixels. The size of the object to be mesured is 2 m. In case of these data, how would you estimate the accuracy of the measurements in the object.
4. You have to calibrate a video camera which will be used for a 3-D measuring task, where the expected accuracy of the image obzservations would be about 1/10 pixels on images. For the calibration the camera is fixed and mounted to a real-time photogrammetric station which uses retro reflectors for image observations. The calibration will be performed in combination with the calibration of the photogrammetric station. Prepare the work plan, where you describe step by step the calibration procedure. You should also describe which camera parameters are to be calibrated.
5. Kamerakalusto voidaan kalibroida mittauksen aikana eli 'on-the-job'. Kerro, miten 'on-the-job'-kalibrointi tehdään. Arvioi myös 'on-the-job'-kalibrointia sen hyvien ja huonojen ominaisuuksien kannalta.