Abstract: An underwater detection system is provided that can effectively use a discrimination result. A fish detector of the system is configured to implement a discrimination function including a fish species discrimination function; however, a fish detector and a sonar of the system do not comprise such a discriminator including a fish species discriminator. The fish detector transmits various discrimination results such as fish species discrimination, etc., through an onboard LAN to the fish detector or the sonar. The fish detector and the sonar superimpose various received discrimination results on the detection result of the device itself and display them on a display.

Abstract: An underwater detection system is provided that can effectively use a discrimination result. A fish detector of the system is configured to implement a discrimination function including a fish species discrimination function; however, a fish detector and a sonar of the system do not comprise such a discriminator including a fish species discriminator. The fish detector transmits various discrimination results such as fish species discrimination, etc., through an onboard LAN to the fish detector or the sonar. The fish detector and the sonar superimpose various received discrimination results on the detection result of the device itself and display them on a display.

Abstract: An underwater detection apparatus for detecting a target by transmitting and receiving an ultrasound signal is provided. The apparatus includes a replica memory module for storing the typical amplitude evolution of a seawall echo during a predetermined time period as a template-replica beforehand, a correlator module for determining a correlation between the amplitude evolution of an echo signal reflected from the target and the template-replica, a seawall detector module for detecting a seawall position based on the correlation, and a seawall display processor module for displaying the seawall on its position in an indicator.

Abstract: In an under water detection for detecting the phase difference of an echo by two reception beams according to a split beam method, the difference ?? between the phase difference of an echo detected by first and second reception beams formed in some direction and the phase difference of the echo detected by first and second reception beams which is formed in a direction rotated from the former direction concerned by a predetermined angle is detected by a phase detector. A reliability judging unit judges whether the difference ?? detected by the phase detector is within a predetermined range or not. If the difference ?? is within the predetermined range, an echo is displayed on a display unit. If the difference ?? is not within the predetermined range, the echo is displayed with a specific color tone or the echo is not displayed.

Abstract: An underwater detection apparatus for detecting a target by transmitting and receiving an ultrasound signal is provided. The apparatus includes a replica memory module for storing the typical amplitude evolution of a seawall echo during a predetermined time period as a template-replica beforehand, a correlator module for determining a correlation between the amplitude evolution of an echo signal reflected from the target and the template-replica, a seawall detector module for detecting a seawall position based on the correlation, and a seawall display processor module for displaying the seawall on its position in an indicator.

Abstract: In an under water detection for detecting the phase difference of an echo by two reception beams according to a split beam method, the difference ?? between the phase difference of an echo detected by first and second reception beams formed in some direction and the phase difference of the echo detected by first and second reception beams which is formed in a direction rotated from the former direction concerned by a predetermined angle is detected by a phase detector. A reliability judging unit judges whether the difference ?? detected by the phase detector is within a predetermined range or not. If the difference ?? is within the predetermined range, an echo is displayed on a display unit. If the difference ?? is not within the predetermined range, the echo is displayed with a specific color tone or the echo is not displayed.