Computational imaging technology
2018, 47(10): 1041001.
doi: 10.3788/IRLA201847.1041001
Correlated imaging was a new type of imaging technology, with great application value and promising prospect, which has recently become a hotspot and one of the frontiers of optical imaging researches. Polarization detecting method can improve system's ability of object detection and recognition, and categorize detected objects based on its materials. By combining correlated imaging with polarization detection, a correlated imaging system was built based on forward modulated polarization, which utilized fixed probe side polarization configuration and used Hadamard mode speckles modulated by time-shared polarization method to illuminate scenes. The system was used to carry out the polarization detection imaging experiments for the scenes with multi-material objects. The intensity and polarized images of scenes were retrieved using the correlation between the detected intensities and illumination speckles. Using evolutionary compressed sampling restoration techniques, the information of scenes was reconstructed under different sampling ratios. The clear images of the intensity and polarization are obtained under the sampling ratio of 12.5%.
2018, 47(10): 1041002.
doi: 10.3788/IRLA201847.1041002
Correlation imaging is an innovative imaging scheme, which transforms the imaging time to a spatial resolution by a single pixel detector. However, there are problems of low reconstruction quality and long data acquisition time. Hadamard coded modulation computation correlation imaging can achieve efficient imaging and significantly improve the applicability, but the noise in imaging reconstruction, which restricted the practicability, is a challenge needs to be tackled urgently. A correlation imaging related noise suppression scheme was proposed by thresholding method and morphological image enhancement, by analyzing the noise characteristics of the reconstructed results of the correlation imaging, which the Hadamard matrix as a measurement matrix and the feasibility of this scheme was verified by experiments, and nearly 8 dB enhancement of optical image was achieved. This imaging scheme is efficient for two valued images and grayscale images, and its work promotes the practicability of correlation imaging technology.
2018, 47(10): 1041003.
doi: 10.3788/IRLA201847.1041003
Reflectance Confocal Microscopy for skin (RCM) is an important skin imaging diagnostic tool, which uses resonant galvanometer that will result in nonlinear distortion at image. In order to correct the distortion, a method of anti-sine signal oversampling based pixel using isochronous sampling system to correct the distorted RCM image caused by resonant galvanometer was presented. The results of experiments on the rectangular grating with a pitch of 20 m indicate that, the standard deviation of the grating spacing is 7.78 m. The distortion rate of image before being corrected is 38.9%. The standard deviation of the image corrected by the anti-sine signal over-sampling based pixel method is 0.85 m, so the distortion rate is reduced to 4.2%. According to the results of a resolution plate and the actual human skin imaging, the distortion correction method proposed in this paper can correct the image distortion caused by resonant galvanometer and meet the human skin real-time non-invasive imaging diagnostic requirements.
2018, 47(10): 1041004.
doi: 10.3788/IRLA201847.1041004
Time of flight (TOF) three-dimensional imaging technology has the advantages of active parallel detection in the frame, good real-time acquisition of scene information, small influence of ambient light, high accuracy of detection data, strong anti-sport interference and low average power consumption. In three-dimensional intelligent sensing, industrial inspection, SLAM and other fields have a wide range of applications, especially in autonomous navigation, driving control and intelligent systems as a real-time three-dimensional imaging information of the sensor has been rapidly developed. The principle and characteristics of two kinds of TOF imaging were studied. Two types of TOF imaging principle and characteristics, system composition were discussed. TOF imaging system was compared with other mainstream three-dimensional imaging technology. Its main source of error and type was classified and analyzed, its error model was studied. As a new generation of three-dimensional imaging technology, TOF is still in the development stage, which can effectively enhance the imaging perception and measurement level of the intelligent system and promote the technological progress in related fields.
