Browsing by Subject "automatic measurement"

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Access status: Open Access ,
Automatyczna detekcja i pomiar markerów w fotogrametrycznym systemie trójwymiarowego pozycjonowania ciała dla celów rehabilitacji leczniczej
(Wydawnictwa AGH, 2006) Tokarczyk, Regina ; Huppert, Michał
Photogrammetric system of positioning for the purpose of medical rehabilitation is based on the images of digital cameras and allows the determination of spatial co-ordinates of selected points of human body. These points consist of characteristic places of skeleton transferred into the surface of human body. They are marked by light foamed polystyrene balls. Apart from these points, also patients' pupils were examined. Reference system is defined by flat paper sheets situated in one surface. The mentioned above points are measured manually, which makes the system not very competitive compared to other systems working in this field. In the framework of developing and modernizing this system, studies on automatic detection and measurement in digital images of the mentioned above three groups of points were carried out. For the detection of markers on the patient's body the method of searching referring to a defined colour was chosen. This search is carried out in the HSI area of colours. For the groups of pixels discovered in the pair of images and making images of markers - centres are determined and then connected into homological pairs based on the following criteria: belonging to a proper epipolar line and minimum of vertical parallax. The proposed method was compared to the manual measurement and it was successful in terms of its accuracy. Because amateur compact digital cameras, used for the recording of the image, save this image in JPG, causing quality loss, the influence of the degree of compression on the accuracy of automatic measurement was examined.
Access status: Open Access ,
Badanie przestrzeni barwnej cyfrowego aparatu fotograficznego na przykładzie Minolty Dynax 5D
(Wydawnictwa AGH, 2006) Pirowski, Tomasz ; Tokarczyk, Regina
The proposed method of the automatism of the measurement of markers in a photo-grammetric system of 3D positioning for medical rehabilitation purposes is based on the detection of colours. Because the parameters of the calibration of colours determined based on one photo-graph are used in searching in many photographs, it is important to investigate how accurate in projecting colours a picture registering device (digital photo-camera) is. The studies referring to this phenomenon were carried out for the photo-camera Minolta Dynax 5D. A transparent test IT8 of known colour parameters in model $L*a*b$. was used in the studies. The experiments were made at day-light and artificial light, with different white balance and different speed of CCD. The results of the registration were compared in a formal and visual way with the pattern calculated into the space of colours RGB. Formal (statistic) approach allowed the detection of a difference on respective components R, G and B and defining standard deviation (noise) in single colour fields and the greyscale. In the conclusions it was stated which colours and which components get most deformed and in which range the colour balance for the greyscale is kept properly. To generalize - in order to compare different tests and - in the future - different digital cameras - a synthetic parameter was used - a so-called mean relative spectral error nQ - proposed by Wald.