Fig. 1. Binary PWM-sequence pattern with three examples of how light intensities have different gray levels.

Fig. 2. (left) Conventional binary CGH and (right) binary-weighted CGH.

Fig. 3. Light intensities of the reconstructed object points from binary-weighted CGHs with different gray levels.

Fig. 4. Assignment of the object points of the 3D object to the bit planes consisting of binary-weighted CGHs with different gray levels.

Fig. 5. Gradation object points reconstructed from multiple bit planes using the time-division display.

Fig. 6. Optical setup for the measurement of the light intensity of the reconstructed real image from a binary-weighted CGH.

Fig. 7. Reproduction of bit planes in video mode for the RGB colors using the DMD system.

Fig. 8. Simple assignment of three bit planes B0−B2 in the video mode of the DMD system.

Fig. 9. Reconstructed real images corresponding to gray levels one to seven in Fig. 4 when the grayscale values of the binary-weighted CGHs corresponding to the bit planes B0−B2 are respectively set to 70, 153, and 223.

Fig. 10. Average light intensities of the 49 object points shown in Figs. 9(a) to 9(g) with grayness levels one to seven in Fig. 4.

Fig. 11. Original 3D model. (left) The vertices of the “Stanford bunny” without the object points on the hidden surface. (right) Original 3D model with gradation.

Fig. 12. Optical setup for evaluating the reconstructed 3D image using the proposed method.

Fig. 13. Reconstructed real images using the proposed method. (left) The grayscale values of the bit planes B0, B1, and B2 are 35, 65, and 110, respectively. (center) The grayscale values of the bit planes B0, B1, and B2 are 60, 110, and 170, respectively. (right) The grayscale values of the bit planes B0, B1, and B2 are 90, 150, and 255, respectively.