Endoscope

1. An endoscope configured to measure a specimen using a stripe image formed by projecting a light and dark pattern on the specimen, the endoscope comprising:

an insertion portion having an elongated shape;

an imaging unit provided at a distal portion of the insertion portion and configured to acquire an image of the specimen;

a lighting unit configured to illuminate an observation field of view of the imaging unit;

a pattern projector having a light source configured to emit projection light to project the light and dark pattern on the specimen; and

a display having a display screen configured to display the image of the specimen;

wherein the pattern projector generates a region, in which the light and dark pattern is not projected, in at least one end of a direction in which stripes of the light and dark pattern are arranged in an imaging field of view of the imaging unit, in a state in which the light and dark pattern is projected on the specimen;

wherein the display displays a frame on the display screen, and the frame shows a predicted projection position on the display screen of the light and dark pattern projected on the specimen;

wherein the imaging unit includes an image sensor configured to image the specimen, and an objective optical system configured to form the image of the specimen on the image sensor;

wherein the pattern projector includes a pattern generator configured to generate the light and dark pattern, and a projection optical system provided at the distal portion of the insertion portion and configured to radiate the projection light from the light source to the specimen via the light and dark pattern;

wherein a radiation angle of the projection light in the projection optical system is smaller than an angle of view of the objective optical system; and

wherein the objective optical system is in focus at a point on a farther side than an object distance at which the entire projected pattern enters an imaging field of view of the image sensor.

2. The endoscope according to claim 1 , wherein the display displays the frame on the display screen even when the light and dark pattern is not projected on the specimen.

3. The endoscope according to claim 2 , further comprising a controller configured to switch an observation mode for observing the specimen and a measurement mode for measuring the specimen,

wherein the display displays the frame on the display screen when the controller switches to the measurement mode from the observation mode.

4. The endoscope according to claim 1 , further comprising a video processor configured to generate an image of the frame, overlap the image of the frame onto the image of the specimen acquired by the imaging unit, and output the overlapped image to the display.

5. The endoscope according to claim 4 , wherein the video processor overlaps the image of the frame onto the image of the specimen even when the light and dark pattern is not projected on the specimen.

6. The endoscope according to claim 5 , further comprising a controller configured to switch an observation mode for observing the specimen and a measurement mode for measuring the specimen,

wherein the video processor overlaps the image of the frame onto the image of the specimen when the controller switches to the measurement mode from the observation mode.

7. The endoscope according to claim 1 , further comprising a controller configured to measure the specimen using only the image of specimen displayed within the frame.