Underwater De-scattering Imaging by Laser Field Synchronous Scanning

Underwater Optical Imaging: Key Technologies and Applications Review

“…The methods such as range-gated imaging [19], laser synchronous scanning [20], and streak tube imaging [21] have eliminated stray light through temporal or spatial separation, the obtained images are the mixture of medium transmittance and target image. Polarization imaging [22] and ghost imaging [24] both consider the medium transmittance, and the obtained images are closest to the initial target image.…”

“…The depth of field of the system can be extended by using synchronous scanning, which can be achieved by mechanical synchronization and signal synchronization. According to the difference of the sampling methods, laser synchronous scanning can be classified into three types: laser point scanning (LPS) [41], laser line scanning (LLS) [42], and laser field scanning (LFS) [20]. LPS adopts a point-bypoint scanning method with the advantages of a concentrated beam energy and high imaging resolution, however, the imaging speed is slow, which limits the practical application.…”

“…Compared with conventional LLS, this method reduces the mechanical complexity and improves system stability without the translation requirement of the receiver. In 2020, Wu et al [20] introduced an underwater LFS system. The system equips a scientific CMOS (sCMOS) camera with short exposure time and high sensitivity to acquire a narrow FOV in rolling shutter mode.…”

“…Based on the novel imaging mechanisms, the whole imaging system is changed and improved to directly restore the underwater images. This includes range-gated imaging [19], laser synchronous scanning [20], streak tube imaging [21], polarization imaging [22], spectral imaging [23], and ghost imaging [24]. Table 1 presents the comparison between various underwater optical imaging techniques.…”