There are many successful applications of deep learning in solving challenging and difficult problems in recent years. An excellent example is its application in medical image analysis. Dr. Heng’s group is the first to employ 3D multi-level contextual 3D convolutional neural network framework for false positive reduction in automated pulmonary nodule detection. They further proposed a novel and efficient 3D CNN equipped with a 3D deep supervision mechanism to comprehensively address the challenges of optimization difficulties of 3D networks and inadequacy of medical training samples. Their successful deep learning applications cover a wide spectrum of medical image modalities， include histopathlogical imaging， ultrasound imaging， MR/CT imaging， dermoscopy imaging. Concurrently， there are also many significant and promising developments in virtual reality that are applicable for medical applications. Virtual reality based surgical simulation can provide a cost-effective and efficient way to train novices. In order to achieve the goal of delivering specialized training of a surgical procedure， one practical solution is to construct a realistic virtual environment through intelligent integration of medical imaging， motion tracking， physically based simulation， haptic feedback and visual rendering. In this review， Dr. Heng will present their recent works in using deep learning for medical image analysis and introduce some VR-based surgical simulators they have developed.

SF6 is the most commonly used insulating gas in gas insulated equipment. It is important to know the composition and content of decomposition components to timely and accurately judge the insulation and aging of equipment. Therefore， based on Raman spectroscopy technology， a set of Raman detection system is designed in this paper， which is composed of gas measurement module， function module， embedded control module， computer module and others， with the functions of temperature and pressure control， signal enhancement， mixed gas detection and analysis. The experiment of Raman system is carried out with SF6 and its decomposed components mixture. The characteristic peaks of SF6， SO2F2， SO2， CO2， CO， and H2S are 776 cm-1， 861 cm-1， 1 138 cm-1 and 1 378 cm-1， 1 269 cm-1， 2 185 cm-1， 2 600 cm-1 respectively， which are consistent with the NIST standard values. It is proved that the Raman spectrum detection system is feasible and provides a good basis for the detection of SF6 decomposition components， which is of great significance to ensure the safe and stable operation of power grid.

Aiming at the problem that the measurement accuracy of image tracker diverges with external factors， an image tracker detection method based on autocollimator is proposed in this paper. Using the super high angle measurement accuracy of the reference mirror and autocollimator on the back of the image tracker， the fast calibration and detection of the measurement accuracy of the image tracker are realized， and the measurement accuracy is 2.5″. The experimental results show that the measurement accuracy of the image tracker changes with the environmental stress， and the image tracker detection method based on autocollimator can realize the measurement of its accuracy.

Future warfare will develop towards the integration of sea， land， air and space， and the development of massive data informatization. As an important target of marine information perception， the development of ship detection technology is of great significance to infrared security defense systems. Based on the characteristics of infrared payload imaging the basic framework of infrared target detection is proposed in this paper. And the research status of the three key steps of image preprocessing， rough target inspection and target identification is introduced in details. On this basis， various algorithms are compared and their applicability， advantages and disadvantages are pointed out. Finally， the future development trend of infrared target detection is prospected.

In view of the problem that urban cables or communication cables are often damaged by external forces caused by municipal construction， a monitoring method based on optical sensing technology for power pipeline optical cables is proposed in this paper. The principle and architecture of the monitoring system are analyzed and studied. The vibration device is used to simulate the test above the optical cable channel， and the field data are analyzed and verified. The results show that the power pipeline optical cable anti-damage monitoring system based on optical sensing technology can realize the monitoring and identification of the external damage vibration signal， and the field application effect is better.

The light-guiding co-aperture optoelectronic imaging system has the characteristics of small rotating load， multiband co-aperture， and can achieve static sealing. At present， it is widely used in optoelectronic devices on multiple platforms. However， compared with the turret type optoelectronic equipment， there is a problem of image rotation. The relative error of the optical axis of the turret-type optoelectronic equipment remains unchanged at different azimuths and pitch angles， so a fixed amount of deflection can be directly given to the tracking viewing axis to ensure the unity of each viewing axis. Due to the existence of image rotation， the relative error of the optical axis of the light-guiding co-aperture optoelectronic device is not consistent at different azimuths and elevation angles. The typical optical path of the light-guided co-aperture optoelectronic tracking device is taken as the analysis object in this paper. The change law of the relative error of the optical axis caused by the image rotation is analyzed in details. The compensation formula is given， and the experimental verification is carried out. The results show that the approximate formula derived in this paper can effectively compensate the relative error of the optical axis of the light-guided co-aperture optical path.

The polarization change of the hollow beam (HLB) is theoretically studied， and its focusing characteristics are studied based on the Richards-Wolf vector diffraction integral theory. The changes in the size and shape of the focused spot at different numerical apertures are obtained. It is found that the circularly polarized hollow beam and the vertically polarized hollow beam mainly changes in the size of the focused spot， while the horizontally polarized hollow beam and the radially polarized light book change greatly. In addition， a method of converting the vector polarized hollow beam into the scalar polarized hollow beam is proposed. The polarization state of the hollow beam is converted and the power compensation is obtained. The average power of 2.2 W laser output is obtained.

The optical axis stability is an important factor affecting the performance of optical system， and the thermal-structural-optical integrated analysis is an effective evaluation method. The thermal-structural-optical integrated analysis process is expounded in this paper， and the rigid body displacement extraction based on homogeneous transformation method is studied. By the use of this technology， the optical axis stability of a HDTV optical system is studied as well. Through the comparison of theoretical analysis and physical test，the correctness of the simulation analysis method is verified. The analysis results show that， compared with the test result， the error of optical axis stability based on the thermal-structural-optical integrated analysis is 12.1%. The thermal-structural-optical integrated analysis can effectively solve the problem of the optical axis stability of highly integrated optical system.

The freeform surface is a non-rotationally symmetrical surface with strong asymmetric aberration correction capability. In order to meet the requirements of the space remote sensing system for large range and high resolution imaging， an off-axis three-mirror reflective system with large field of view and long focal length is designed by using freeform surfaces. Firstly， the initial configuration with conic surfaces is obtained directly based on the vector aberration theory. The obscuration of the initial configuration is avoided by using the decenter and tilt of the mirrors. Then， freeform surfaces are used to correct the aberration of the initial configuration. The final freeform off-axis three-mirror reflective system is obtained by optimizing the initial configuration. The field of view of the designed system is 16° × 1°， the focal length is 2 000 mm， and the entrance pupil diameter is 235 mm. The modulation transfer function curves are close to the diffraction limit， and the maximum relative distortion is 0.37%. The optical system has good imaging quality within the tolerance ranges.

An integrated optical system design method for LED automobile headlamp is prsent，and an asymmetric dual freeform surface lens is designed for low and high beam. The illumination width of near light can reach 16 meters by using variable focal length ellipsoid reflector and asymmetric double free surface lens. The simulation results show that the illumination value and light type required by the high and low light points of the headlamp meet the national standard， and the color temperature of the spot is stable. The volume of the designed optical system is half of that of the traditional headlamp， which conforms to the requirements of the compact headlamp design.

A new compact polarization beam splitter based on the self-collimation effect of two-dimensional photonic crystals and photonic band gap characteristics is designed in this paper. The size of the entire device is 9 μm×9 μm. The self-collimation effect of photonic crystals is used to realize TE polarized light and TM polarization. The self-collimation propagation of light in the self-collimation structure utilizes the photonic band gap characteristic to realize the orthogonal separation of TE polarization and TM polarization. When the number of air holes of the inserted polarization beam splitting structure is 5， the transmittance of TE polarized light at 1 550 nm is 95.4%， the corresponding polarization extinction ratio is 23 dB， and the transmittance of TM polarized light is 88.5%， which corresponds to the polarization extinction ratio is 37 dB. For TE and TM polarized light covering a 100 nm bandwidth， the TE polarization extinction ratio and TM polarization extinction ratio are higher than 18 dB and 30 dB， respectively. Compared with the previous polarization beam splitter， the structure is simpler， the size is smaller， and the polarization extinction ratio is higher， which better meets the needs of modern optical communications and optical integrateion systems.

The all-optical current transformer(AFOCT) is made up of the optical fiber as the sensor and the optical signal transmission carrier. Optical signal is used as the transmission carrier， and because the optical fiber is easily affected by temperature and has small deformation， the polarization state of optical signal will change in the process of propagation. In this paper， the affection of temperature on the 1/4 wave plate and the fiber sensing ring is analyzed， and the measurement results are optimized. The phase delay of linearly polarized light will change with the change of temperature in 1/4 wave plate made of polarization-maintaining fiber， and the Verde constant of fiber sensing ring is also affected by the environmental temperature. Based on the analysis of the temperature characteristics of the two devices， a temperature compensation optimization scheme is proposed. Compatible with the original optical circuit devices， optical fiber birefringence temperature sensor is designed for the secondary compensation of temperature errors. The maximum range of transformer changes from 0.417% to 0.335% at 70~40 ℃ to meet the requirements of national standard. The product based on the technical solution has passed the inspection of the third party authority and has been applied in the substation project for a long time. The equipment runs stably and the measurement is accurate， which verifies the feasibility and correctness of the scheme.

The airborne INS/GNSS deep integrated navigation system which effectively improves the accuracy and reliability of airborne navigation and positioning， has received extensive attention in recent years. The concept and structure for INS/GNSS scalar and vector deep integrated navigation system is described first in this paper. Then， the status of airborne INS/GNSS deep integrated navigation system is analyzed and compared. In the end， the application and development of domestic related technologies are prospected.

In order to meet the requirements of absolute marine and airborne gravimetry for resource exploration， inertial navigation and positioning， the improvement of miniaturization， portability and high robustness of atomic gravimeter ?is?a?significant?research?subject. The principle and structure characteristics of atomic gravimeter are analyzed， and the main classification and development trend of atomic gravimeter are summarized in this paper. The principles of absolute gravimetry experiments on portable， vehicle-mounted， airborne， elevator and shipboard based on mobile atomic gravimeter are reviewed. The technical characteristics and main indexes of mobile gravimeters are compared， and the development directions of mobile atomic gravimeter used for field testing are preliminarily discussed.

The accuracy and time of initial alignment of shipborne weapon strapdown inertial navigation system (SINS) determine the accuracy and speed of weapon system attack. Because the navigation environment of ship is complex and changeable， the strapdown inertial navigation system (SINS) of shipborne weapon uses the high-precision navigation information provided by the ship's main inertial navigation system (MINS) for traction alignment， which can improve the accuracy and speed of alignment and ensure the smooth completion of combat tasks. In this paper， the performance of shipborne weapon strapdown inertial navigation system using the position and velocity information provided by the main inertial navigation system is analyzed by semi physical simulation， and the alignment performance is evaluated by using the attitude tracking accuracy and time of the main inertial navigation system after the traction alignment. Through the analysis， it is concluded that under static conditions， after the traction transfer alignment is stable， the heading reference transfer error caused by traction transfer is less than 1.8′(0.03°)， and the attitude reference transfer error is less than 10.8″(0.003°). Under the dynamiccondition， when the traction transfer is stable， the heading reference transfer error caused by traction transfer is less than 2.4′(0.04°)， and the attitude reference transfer error is less than 10.8″(0.003°). This paper provides a certain reference for the establishment of the traction alignment model of each subsequent combat platform.

Aiming at the problem that current damping technology for inertial navigation system based on Kalman filter depends on the ground velocity， a horizontal damping method for inertial navigation system based on adaptive delayed state filter is proposed. In this method， a delayed state is introduced so that the ground velocity is not included in the measurement equation. And the measurement noise adaptive theory and delay state filter theory are combined to improve reliability. It is suitable for the damping process of inertial navigation system under the condition that only the water speed can be obtained. Simulation experiments show that the proposed method can use water velocity to achieve damping for system error.

In order to cope with the demand for positioning， navigation and timing (PNT) in the future complex battlefield environment and to build a more reliable PNT capability， China is vigorously promoting the construction of a national comprehensive PNT system with the third generation BeiDou Navigation Satellite System as the core， of which the underwater PNT system is an important part. The underwater PNT system is an important component. Since satellite signals cannot be received underwater， it is required to use inertial navigation system (INS) with higher accuracy as much as possible， and the atomic gyro has very high theoretical accuracy， which provides the possibility to build INS with high accuracy. Therefore， the structure and basic principle of atomic gyro technology from the perspective of underwater PNT system construction requirements are reviewed in this paper.Its development history， research status， problems and application degree at home and abroad are introduced， and the important role and application prospect of atomic gyro in the construction of underwater PNT system are analyzed.