The conventional method used to detect an underwater target is by sending and receiving some form of acoustic energy.
But the acoustic systems have limitations in the range resolution and accuracy; while, the potential benefits of a laserbased
underwater target detection include high directionality, high response, and high range accuracy. Lasers operating
in the blue-green region of the light spectrum(420 : 570nm)have a several applications in the area of detection and
ranging of submersible targets due to minimum attenuation through water ( less than 0.1 m-1) and maximum laser
reflection from estimated target (like mines or submarines) to provide a long range of detection. In this paper laser
attenuation in water was measured experimentally by new simple method by using high resolution spectrometer. The
laser echoes from different targets (metal, plastic, wood, and rubber) were detected using high resolution CCD camera;
the position of detection camera was optimized to provide a high reflection laser from target and low backscattering
noise from the water medium, digital image processing techniques were applied to detect and discriminate the echoes
from the metal target and subtract the echoes from other objects. Extraction the image of target from the scattering noise
is done by background subtraction and edge detection techniques. As a conclusion, we present a high response laser
imaging system to detect and discriminate small size, like-mine underwater targets.
The light interaction with tissue is governed by the specific wavelength of the laser used and the optical properties of
target tissue. Absorption, scattering and fluorescence together can probably be used as the basis of quantitative
diagnostic methods for teeth caries. The absorption coefficient of human teeth was determined from detached wet
teeth (incisors and premolars). Laser absorption of these teeth was measured using compact blue laser source at
wavelength of 457 nm and a high resolution spectrometer equipped with an integrating sphere. The average
absorption coefficient of abnormal caries tissue of human teeth is observed to be higher than the normal ones.
Detection and diagnosis of caries tissues were monitored by high resolution translational scanning of human teeth.
We have a powerful tool to diagnosis a caries region of human teeth using blue laser at 457 nm. Ablations of caries
region are investigated using higher power of blue laser at 457 nm.