## 4 Results
### Light Field Reconstruction  
To test the performances of the diffusive marker approach on a real system, we will look at the actual reconstructed image from the display system shown in Figure 1a-c. To understand the divergence suffered by the reconstructed beam on interaction with the hologram screen, one may refer to [PERSON] et al. [11]. The reconstructed images were captured using a camera placed in the view zone as shown in Figure 2a. Figure 6b-e shows reconstructions for calibrations using both approaches. In this experiment, we moved the camera, prior to calibration, about 10 cm to the left of the center of the screen's viewing zone, to imitate an inaccurate camera placement. The displayed scene (Figure 6a) consists of a ring with four arrows pointing towards the center which is to be reconstructed at 3 cm behind the DDHOE screen. A sphere (ball) is floating about 6 cm in front of the center of the ring which is to be reconstructed at 3 m in-front of the DDHOE screen. When this scene is observed from the front, the arrows should be pointing towards the ball. When the observer moves to the left, the ball should appear in front of the right arrow. Figure 6b,c show views recorded at respectively the left side and the center of the viewing zone for the described scene while utilizing the calibration that does not use the diffusive markers. The location of the camera in the left view (Figure 6b) was the same location as the one during calibration. When we observe the scene from the left side, we can see that the ball is located in the center of the ring. This indicates that we are looking at the central view of the displayed scene, from the left side, which is not correct. When we observed the setup from the center of the viewing zone, the ball touches the left arrow, which indicates that we are looking at a right view of the projected scene. These results reveal the effects of camera positioning offsets during calibration. From this, we can understand that simply assuming the camera to be exactly at the center (where the actual position may be slightly offset) during calibration is not sufficient enough. It also reveals that that during calibration, the central view of the scene, is always camera position dependent, if no additional markers are being used. It is to be noted that the ball appears to be cropped at one side, which is due to the shadow of the 3D content (circle with arrows), casted on the ball. Figure 6d,e show reconstructions using the proposed calibration that utilizes the diffusive corners. The locations of the cameras are the same as those used to capture images Figure 6b,c, and the position of the camera during calibration was also the same as the one in the previous experiment. When observed from the left (Figure 6d), the ball now overlaps the right arrow. This indicates that we are looking at a left view of the projected scene, while observing the display from the left. When observing the scene from the center of the viewing zone, the ball appears to be in the center of the ring. As such, we are observing the center of the scene. This test indicates that a calibration which uses additional markers makes sure that the reconstructed views are projected in the correct directions, contrary to using a calibration without markers. In another experiment, we tested the alignment of the reconstructed scene with an actual object (real scene). To do this, we placed a 3D-printed object at about 3 cm behind the screen. The complete setup can be seen in Figure 7. The 3D-printed object consists of a flat ring and an arrow that points to the center of the ring. Additionally, we created a 3D scene containing a ring 3 cm behind the display (Figure 8a). This ring has the same dimensions as the 3D-printed ring. We also positioned a disc 6 cm in front of the center of the ring, which means that the disc is located 3 cm in front of the display. When correctly calibrated, both the virtual ring and the 3D-printed ring align from all viewpoints. Again, we applied both calibration approaches.