Correlated Imaging Method By Cross-Correlation In Time-Domain

Optical imaging is an important research direction that is widely used and closely related to our lives.Compared with traditional optical imaging,correlated imaging has received wide attention due to its unique imaging structure and certain anti-noise performance.With the deepening of related imaging research,improving the imaging quality of correlated imaging become a common concern.However,in the practical application of correlated imaging,it is necessary to emit light to an object and receive echoes.This process is inevitably interfered by external light sources,which is an important factor affecting the imaging quality.In this paper,the pulse waveform of the light source is considered as a prior information,and by cross-correlation in time domain the information of the object can be extracted from the bucket detection results under the obstruction of the external light source,as a result,reducing external light interference and improving image quality.We use the cross-correlation function of the known pulse waveform and bucket detection results as the new bucket detection results,and use the new bucket detection results to correlate with the reference arm results to obtain the object image.Theoretically,we prove that the image of the object can be obtained by using the cross-correlation function.At the same time,the signal-to-noise ratio(SNR)of bucket detection and imaging contrast-to-noise ratio(CNR)of traditional correlation imaging and time-domain cross-correlation correlated imaging are also calculated.An correlated imaging optical system with variable external light intensity is also built.The imaging effect of time-domain cross-correlation correlated imaging is compared with traditional correlated imaging.It is found that when the SNR of bucket detection is lower than 1,the imaging quality of the time domain cross-correlation correlated imaging is better than that of the traditional pulse correlated imaging.In particular,when the SNR of bucket detection is lower than 0.1,the pulse correlated imaging can still obtain the image of the object,while the traditional pulse correlation imaging can not be distinguished.The experimental results show that time-domain cross-correlation correlated imaging is beneficial to improve the correlation imaging quality under external light sources,and even when the external interference is stronger than the illumination light by an order of magnitude,the object can still be imaged.