Image processing method and image processing apparatus

• US 10,185,886 B2
• Filed: 03/31/2017
• Issued: 01/22/2019
• Est. Priority Date: 05/20/2016
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Baba, Kozo
• Primary Examiner(s): Bernardi, Brenda C
• Application Number:
  US15/475,355
• Publication Number:
  US 20170337445A1
• Time in Patent Office: 662 Days
• CPC Class Codes: G06T 2207/20081 Training; Learning
• CPC Class Codes: G06T 2207/30232 Surveillance
• CPC Class Codes: G06T 2207/30248 Vehicle exterior or interior
• CPC Class Codes: G06T 7/11 Region-based segmentation
• CPC Class Codes: G06T 7/73 using feature-based methods
• CPC Class Codes: G06V 20/625 License plates
• CPC Class Codes: G06V 20/63 Scene text, e.g. street names

Abstract

A method includes obtaining a plurality of images that are continuously captured, detecting a first region indicating a feature value corresponding to a license plate, in a region that indicates a feature value corresponding to a vehicle and that is included in a first image among the plurality of images, based on a feature value of each of the plurality of images, determining a second region in the plurality of images, the second region indicating a feature value corresponding to a license plate, at least a part of the second region overlapping the first region in an image different from the first image, and outputting the second region as a license plate region.

Claims

1. A method executed by a computer, the method comprising:

obtaining a plurality of frames that are sequentially captured from a moving image;

detecting a vehicle region having a characteristic of a vehicle from each of the plurality of frames based on feature values of the plurality of frames;

detecting a plurality of license-plate candidate regions each of which has a characteristic of a license plate, from each of the plurality of frames based on the feature values;

providing a same vehicle ID to the vehicle regions that overlap each other in the plurality of frames;

providing a same plate ID to the license-plate candidate regions that overlap each other in the plurality of frames;

determining whether or not each of the license-plate candidate regions is a first license-plate region, based on a ratio relating to the license-plate candidate region being included in the vehicle region in the frame where the same vehicle ID and the same plate ID are provided;

outputting each of the determined first license-plate regions as a detect target region based on a number of frames including the first license-plate region of the plurality of license-plate candidate regions.

2. The method according to claim 1, further comprising:

calculating a score corresponding to each of the license-plate candidate regions based on the feature values; and

determining the at least one first license-plate region based on the scores when the vehicle region includes two or more license-plate candidate regions.

3. A device comprising:

a memory; and

a processor coupled to the memory and configured to;

obtain a plurality of frames that are sequentially captured from a moving image,

detect a vehicle region having a characteristic of a vehicle from each of the plurality of frames based on feature values of the plurality of frames,

detect a plurality of license-plate candidate regions each of which has a characteristic of a license plate, from each of the plurality of frames based on the feature values,

provide a same vehicle ID to the vehicle regions that overlap each other in the plurality of frames,

provide a same plate ID to the license-plate candidate regions that overlap each other in the plurality of frames,

determine whether or not each of the license-plate candidate regions is a first license-plate region, based on a ratio relating to the license-plate candidate region being included in the vehicle region in the frame where the same vehicle ID and the same plate ID are provided;

output each of the determined first license-plate regions as a detect target region based on a number of frames including the first license-plate region of the plurality of license-plate candidate regions.

4. The device according to claim 3, wherein the processor is configured to:

calculate a score corresponding to each of the license-plate candidate regions based on the feature values, and

determine the at least one first license-plate region based on the scores when the vehicle region includes two or more license-plate candidate regions.