Abstract: A method and a system for automatically detecting nitrogen content, an electronic device and a medium are provided and relate to the field of nitrogen content detection. The method includes: selecting an optimal nitrogen content prediction model from a prediction model base according to a variety and a growth stage of a target crop to obtain a target model; detecting, based on a spectral image of the target crop, a nitrogen content of the target crop by using the target model to obtain a predicted value of the nitrogen content. The optimal nitrogen content prediction model is the model with best performance among a first nitrogen content prediction model constructed based on a hyperspectral vegetation index, a second nitrogen content prediction model constructed based on a sensitive band, and a third nitrogen content prediction model constructed based on a machine learning method.

Abstract: Disclosed is a flexible filter spectral camera. A flexible filter module includes N flexible filter units corresponding to N different wavebands, respectively, where N is a positive integer greater than or equal to 2. A CMOS (Complementary Metal Oxide Semiconductor) module is used to convert incident light into a digital signal. Any one of the N flexible filter units can be switched to a preset position to filter light emitted from a lens and transmit light at a corresponding waveband to the CMOS module. The preset position is between the lens and the CMOS module. An image processor is connected to the CMOS module and is used to convert the digital signal into an image. In accordance with the present disclosure, precision imaging of the lens is achieved, the overlapping accuracy and imaging quality of the images are improved, and meanwhile, the processing efficiency for overlapped images is improved.

Abstract: A screen projection method and a device, the method including performing, by a controlling device, at least one of sending, based on a reliability transmission protocol, in response to an image frame that is to be sent being an I frame, a data packet that carries the image frame, sending, based on the reliability transmission protocol, in response to the image frame being a P frame that meets a first preset condition, the data packet that carries the image frame, or sending, based on a non-reliability transmission protocol, in response to the image frame being a P frame that does not meet the first preset condition, the data packet that carries the image frame.

Abstract: It is provided a recognition device for analyzing a starvation extent of a whiteleg shrimp based on underwater imaging, including a bracket, a camera mounted on a top of the bracket, a plurality of light sources for illumination, and a processor connected with the camera. The processor receives a shrimp image collected by the camera, extracts an edge image of the shrimp after the collected shrimp image is preprocessed, and calculates a movement speed of the shrimp and a quantity of baits after a head and a tail are recognized, to recognize starvation extent of the shrimp. It is also provided a recognition method for analyzing starvation extent of the whiteleg shrimp based on underwater imaging. The present disclosure may guide feeders to feed and realize reasonable culture for the shrimp, by capturing images of the shrimp in time and determining starvation the extent of shrimp.

Abstract: A screen projection method and a device, the method including performing, by a controlling device, at least one of sending, based on a reliability transmission protocol, in response to an image frame that is to be sent being an I frame, a data packet that carries the image frame, sending, based on the reliability transmission protocol, in response to the image frame being a P frame that meets a first preset condition, the data packet that carries the image frame, or sending, based on a non-reliability transmission protocol, in response to the image frame being a P frame that does not meet the first preset condition, the data packet that carries the image frame.

Abstract: Embodiments of this application provide a projection display method and an electronic device, and relate to the field of terminal technologies, to dynamically adjust, based on a quantity of source devices, a parameter of display data projected onto a destination device, so as to improve display smoothness and use experience of a user during projection. The method includes: A source device sends a projection instruction to a destination device, where the projection instruction is used to instruct to project a display interface of the source device onto the destination device for display. The source device receives a first broadcast sent by the destination device, where the first broadcast includes a quantity N of source devices that need to perform projection onto the destination device for display.

Abstract: A method for rapid and quantitative determination of sildenafil in cocktail includes the exemplary steps of: Step 1, assigning a Raman spectrum of sildenafil; Step 2, weighing and dissolving a sildenafil standard in methanol to obtain a 1,000 mg/L sildenafil standard solution, and mixing cocktails with the sildenafil standard solution, to prepare test solutions; Step 3, mixing 100 ?L each of test solutions with 500 ?L of surface enhancer OTR 202 to acquire Raman spectra; and Step 4, establishing a linear regression model, with a formula of y=4035.1 x+503.26, where y is the content of sildenafil in cocktail, in mg/L, and x is intensity of Raman characteristic peaks at 1584 cm?1. Rapid determination of sildenafil by SERS is feasible and reliable, serving as a novel, rapid, and accurate method for quantitative determination of sildenafil in cocktail. The method meets the requirements of analysis and detection of sildenafil in other alcoholic beverages.

Abstract: The present disclosure relates to a method and system for the in-situ detection of cadmium chelates in a plant. The method includes: preparing cadmium chloride and phytochelatin (PC) 2 samples with different concentrations; using terahertz time-domain spectroscopy (THz-TDS) to determine a terahertz (THz) reflection image for the cadmium chloride and PC 2 samples; building a cadmium chloride content detection model according to first spectral data; building a PC 2 content detection model according to second spectral data; determining an optimal mixed sample according to the cadmium chloride content detection model and the PC 2 content detection model; building a Cd—PC2 content detection model according to the optimal mixed sample; and using the Cd—PC2 content detection model to determine a cadmium chelate content in a to-be-tested plant. The present disclosure can quickly and in-situ detect the heavy metal accumulation capacity of a plant.

Abstract: The present disclosure relates to a method and system for the in-situ detection of cadmium chelates in a plant. The method includes: preparing cadmium chloride and phytochelatin (PC) 2 samples with different concentrations; using terahertz time-domain spectroscopy (THz-TDS) to determine a terahertz (THz) reflection image for the cadmium chloride and PC 2 samples; building a cadmium chloride content detection model according to first spectral data; building a PC 2 content detection model according to second spectral data; determining an optimal mixed sample according to the cadmium chloride content detection model and the PC 2 content detection model; building a Cd—PC2 content detection model according to the optimal mixed sample; and using the Cd—PC2 content detection model to determine a cadmium chelate content in a to-be-tested plant. The present disclosure can quickly and in-situ detect the heavy metal accumulation capacity of a plant.

Abstract: It is provided a recognition device for analyzing a starvation extent of a whiteleg shrimp based on underwater imaging, including a bracket, a camera mounted on a top of the bracket, a plurality of light sources for illumination, and a processor connected with the camera. The processor receives a shrimp image collected by the camera, extracts an edge image of the shrimp after the collected shrimp image is preprocessed, and calculates a movement speed of the shrimp and a quantity of baits after a head and a tail are recognized, to recognize starvation extent of the shrimp. It is also provided a recognition method for analyzing starvation extent of the whiteleg shrimp based on underwater imaging. The present disclosure may guide feeders to feed and realize reasonable culture for the shrimp, by capturing images of the shrimp in time and determining starvation the extent of shrimp.

Abstract: A method for rapid and quantitative determination of sildenafil in cocktail includes the exemplary steps of: Step 1, assigning a Raman spectrum of sildenafil; Step 2, weighing and dissolving a sildenafil standard in methanol to obtain a 1,000 mg/L sildenafil standard solution, and mixing cocktails with the sildenafil standard solution, to prepare test solutions; Step 3, mixing 100 ?L each of test solutions with 500 ?L of surface enhancer OTR 202 to acquire Raman spectra; and Step 4, establishing a linear regression model, with a formula of y=4035.1 x+503.26, where y is the content of sildenafil in cocktail, in mg/L, and x is intensity of Raman characteristic peaks at 1584 cm?1. Rapid determination of sildenafil by SERS is feasible and reliable, serving as a novel, rapid, and accurate method for quantitative determination of sildenafil in cocktail. The method meets the requirements of analysis and detection of sildenafil in other alcoholic beverages.