1. A method for inspecting a front surface shape, comprising: projecting a stripe pattern of light and dark segments on a transparent plate-shaped object;
capturing a reflection image of the stripe pattern produced by a front surface and a rear surface of the transparent plate-shaped object with a camera;
determining whether a signal wave corresponding to the reflection image captured by the camera is in a state that a first signal wave portion corresponding to a first dark portion of the stripe pattern reflected from the front surface and a second signal wave portion corresponding to a second dark portion of the stripe pattern reflected from the rear surface are separated from each other and do not coincide;
analyzing the signal wave corresponding to the reflection image captured by the camera to recognize a signal wave that corresponds to an image reflected from the front surface, wherein the first signal wave portion is determined by comparing magnitudes of the first and second signal wave portions to determine lowest intensity portions as the first signal wave portions, the lowest intensity portions corresponding to the image reflected only by the front surface; and
using the first signal wave portions which correspond to the image reflected only by the front surface to inspect the front surface shape.
2. The method of claim 1, further comprising:
selecting the stripe pattern so that a length of a first interval between a first low intensity portion in the image signal of a front surface reflection image to a second low intensity portion in the image signal of a rear surface reflection image adjacent to the first low intensity portion is different than a second interval between the second low intensity portion in the image signal of the rear surface reflection image to another first low intensity portion in the image signal of a front surface reflection image adjacent to the second low intensity portion.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An engine control unit for a water jet propelled boat comprising:
a throttle angle sensor for sensing detected throttle angle;
an engine speed sensor for sensing detected engine speed;
a memory device for storing an engine speed preset value and a throttle angle present value;
a turbocharger; and
a steering angle sensor for sensing detected steering angle;
wherein the engine control unit switches ignition timing from a normal mode to an advance angle control mode when the detected engine speed exceeds an engine speed preset value, the detected throttle angle is less than a throttle angle preset value, and the detected steering angle is less than a steering angle preset value.
2. The engine control unit according to claim 1, further comprising:
a timer adapted to limit the duration of the advance angle control mode.
3. An engine control unit for a water jet propelled boat comprising:
an engine including a user controlled throttle that regulates engine speed, and a turbocharger;
a steering angle sensor for sensing detected steering angle; and
means for automatically maintaining engine speed for a set time when the user controlled throttle is moved towards a closed position provided the engine speed exceeds a preset value, wherein the means for automatically maintaining engine speed switches ignition timing from a normal mode to an advance angle control mode when a detected engine speed exceeds the engine seed preset value, a detected throttle angle is less than a throttle angle preset value, and a detected steering angle is less than a steering angle preset value.