Research On Underwater Imaging Technology Based On Electromagnetic Wave Characteristics

Since the underwater environment is much more complicated than on land,it is difficult to directly obtain high quality underwater images when imaging underwater.It is completely different from the atmospheric environment.When electromagnetic waves are transmitted underwater,the water body acts as a transmission medium,which will attenuate the electromagnetic waves,and the electromagnetic waves of different frequencies will transmit differently when the underwater waves are transmitted underwater.This results in underwater images that are directly acquired,often with reduced resolution,reduced contrast,color distortion,and shape distortion.Aiming at the above problems,this paper builds a new underwater image restoration model based on the imaging physical model,combined with the physical characteristics of electromagnetic waves transmitting underwater,and proposes two image restoration methods.Aiming at the shortcomings of dark channel prior theory in underwater image restoration,this paper proposes an image sharpening algorithm based on wavelength-transmittance relationship to estimate the transmittance of each channel.For R,G,B color images,the absorption and scattering effects of water on B channel are relatively small,followed by G channel,and the absorption and scattering effects on R channel are the largest.The electromagnetic wave for different frequencies has a large difference in attenuation when transmitting underwater.The dark channel method is used to estimate the transmittance of the B channel,and the transmittance of the R and G channels is estimated according to the wavelength transmittance ratio.The background intensity is estimated using the statistical average method.A restored image is obtained from the underwater imaging model.The test results show that the method can greatly improve the contrast and sharpness of underwater images.According to the different degrees of energy attenuation of different channels and the influence of the accuracy of water background light estimation on the restoration results,this paper proposes an underwater image sharpening algorithm based on the residual ratio of electromagnetic energy and background light estimation.Aiming at the problem that the background intensity of the water body has a great influence on the imaging,the background light of the water body is accurately estimated according to the background light formation principle.For the huge difference of energy attenuation of each channel,the K channel is used to estimate the B channel transmittance and scattering coefficient using the dark channel,and the scattering coefficient of other channels is estimated by the linear relationship of the wavelength-scattering coefficient and the transmittance is calculated.For the problem of serious color shift,the residual energy ratio of electromagnetic wave and the least square method determine the distance D between the target and the water surface,thereby estimating the energy attenuation from the water surface to the water depth D,and realizing the compensation of the restored image color.The experimental results show that the recovery effect of this method is very obvious,the color reproduction degree is very high,and the effect is better than other traditional methods.