Visibility estimation device, visibility estimation method, and safe driving support system

14:

• A visibility estimation device comprising:
• an image recognizer to detect a landmark by analyzing an image;
• an information storage to record, as a detection history regarding the landmark in the past, an image analysis result of the landmark detected by the image recognizer and a detection position where the landmark is detected by the image recognizer;
• and
• a visibility judger to estimate, in a case when the landmark corresponding to the detection history is detected again by the image recognizer, change in visibility on the basis of comparison between a detection position in the case and the detection position in the past recorded in the information storage.

15:

• The visibility estimation device in claim 14, wherein:
• a plurality of detection histories is recorded by the information storage in accordance with a plurality of usage conditions;
• and
• one of the detection histories being different in accordance with each of the usage conditions is employed by the visibility judger as a comparison target.

17:

• The visibility estimation device in claim 14, wherein:
• a threshold is used by the visibility judger in the comparison for estimating the change in visibility;
• and
• a judgment criterion adjuster is provided to adjust, when the change in visibility is estimated by the visibility judger, the threshold on the basis of change in user's behavior.

20:

• A visibility estimation device comprising:
• an image recognizer to detect a landmark by analyzing an image;
• an information storage to record, as a detection history regarding the landmark in the past, an image analysis result of the landmark detected by the image recognizer and a detection position where the landmark is detected by the image recognizer;
• and
• a visibility judger to estimate change in visibility on the basis of comparison between image analysis progress of the landmark analyzed again by the image recognizer at the detection position in the past recorded in the information storage and the image analysis result in the past recorded in the information storage.

21:

• The visibility estimation device in claim 20, wherein:
• the detection history is recorded by the information storage for each type of landmarks;
• and
• the change in visibility is estimated by the visibility judger in a case when a landmark being a same type with the landmark corresponding to the detection history is detected again by the image recognizer.

22:

• The visibility estimation device in claim 20, wherein:
• a plurality of detection histories is recorded by the information storage in accordance with a plurality of usage conditions;
• and
• one of the detection histories being different in accordance with each of the usage conditions is employed by the visibility judger as a comparison target.

24:

• The visibility estimation device in claim 20, wherein:
• a threshold is used by the visibility judger in the comparison for estimating the change in visibility;
• and
• a judgment criterion adjuster is provided to adjust, when the change in visibility is estimated by the visibility judger, the threshold on the basis of change in user's behavior.

27:

• A visibility estimation device comprising:
• an image recognizer to detect a landmark by analyzing an image;
• an information storage to record, as a detection history regarding the landmark in the past, a detection distance from a position where the landmark is detected by the image recognizer to the landmark;
• and
• a visibility judger to estimate, in a case when the landmark corresponding to the detection history is detected again by the image recognizer, change in visibility on the basis of comparison between a detection distance in the case and the detection distance in the past recorded in the information storage.

28:

• The visibility estimation device in claim 27, wherein:
• the detection history is recorded by the information storage for each type of landmarks;
• and
• the change in visibility is estimated by the visibility judger in a case when a landmark being a same type with the landmark corresponding to the detection history is detected again by the image recognizer.

29:

• The visibility estimation device in claim 27, wherein:
• a plurality of detection histories is recorded by the information storage in accordance with a plurality of usage conditions;
• and
• one of the detection histories being different in accordance with each of the usage conditions is employed by the visibility judger as a comparison target.

31:

• The visibility estimation device in claim 27, wherein:
• a threshold is used by the visibility judger in the comparison for estimating the change in visibility;
• and
• a judgment criterion adjuster is provided to adjust, when the change in visibility is estimated by the visibility judger, the threshold on the basis of change in user's behavior.

34:

• A visibility estimation device comprising:
• an image recognizer to detect a landmark by analyzing an image;
• an information storage to record a reference detection distance from a position where the landmark can be detected by the image recognizer to the landmark;
• and
• a visibility judger to estimate, in a case when the landmark is detected by the image recognizer, change in visibility on the basis of comparison between a detection distance in the case and the reference detection distance recorded in the information storage.

35:

• The visibility estimation device in claim 34, wherein:
• the reference detection distance is recorded by the information storage for each type of landmarks;
• and
• the change in visibility is estimated by the visibility judger, in a case when a landmark is detected by the image recognizer, by using a reference detection distance, recorded in the information storage, of a landmark being a same type with the detected landmark.

37:

• The visibility estimation device in claim 34, wherein:
• a threshold is used by the visibility judger in the comparison for estimating the change in visibility;
• and
• a judgment criterion adjuster is provided to adjust, when the change in visibility is estimated by the visibility judger unit, the threshold on the basis of change in user's behavior.

40:

• A safe driving support system comprising:
• an image recognizer to detect a landmark by analyzing an image;
• an information storage to record, as a detection history regarding the landmark in the past, an image analysis result of the landmark detected by the image recognizer and a detection position where the landmark is detected by the image recognizer;
• a visibility judger to estimate, in a case when the landmark corresponding to the detection history is detected again by the image recognizer, change in visibility on the basis of comparison between a detection result in the case and the detection history in the past recorded in the information storage;
• an information provision determinator to reduce, when current visibility is estimated by the visibility judger to be decreased compared to visibility in the past, a threshold for determining that safety support information regarding surroundings is necessary to be provided to a user;
• and
• a display to provide, when provision of the information is determined by the information provision determinator, the information to the user.

41:

• A safe driving support system comprising:
• an image recognizer to detect a landmark by analyzing an image;
• an information storage to record, as a detection history regarding the landmark in the past, an image analysis result of the landmark detected by the image recognizer and a detection position where the landmark is detected by the image recognizer;
• a visibility judger to estimate, in a case when the landmark corresponding to the detection history is detected again by the image recognizer, change in visibility on the basis of comparison between a detection result in the case and the detection history in the past recorded in the information storage;
• an information provision determinator to reduce, when current visibility is estimated by the visibility judger to be decreased compared to visibility in the past, a threshold for determining that safety support information regarding surroundings is necessary to be provided to a user;
• and
• a speaker to provide, when provision of the information is determined by the information provision determinator, the information to the user.