Real data

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Real data

The acquisition system used was already presented in Section 3.1, now it is used to measure the accuracy of the correspondence analysis using real data. The images have to be rectified to achieve correct results. The position and size of the objects in space is known and, as in the last chapter, used to calculate the true disparities. The translation vectors are given by

Using Equation 2.36, the baseline is given by . The focal length of the left camera is
px. For the computation the bigger value of the focal lengths is used. Figure 4.8 shows the left and right image. The objects that are inside the view of the cameras are a wooden cone and a metallic cube. The properties of these objects have already been described in Section 4.2.2.

Figure 4.8:
The figure shows a pair of real images and their corresponding edge images. The top left image shows also the result of the correspondence analysis. The red and green lines corresponds to each other.

Table 4.5 shows the true and the calculated disparities. The distance between the camera and the objects have been manually measured, thus are affected by an error which is about +/- 2cm. The maximum disparity error rises up to 5px. Which, in the case of Table 4.5, results in a deviation of 4.3 cm in the camera coordinate system. The mean disparity error is given by 2.12 px.

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Up: Correspondence Analysis