Image correction device

An image correction device comprising:

• an electronic controller including at least one processor, the electronic controller being configured to execute a plurality of modules including
• a line segment detection module that detects a plurality of line segments corresponding to a notation on a surface of a document from a captured image obtained by photographing the document;
• a shape specification module that specifies a shape approximation line that approximates a surface shape of the document from the plurality of line segments;
• and
• an image correction module that utilizes the shape approximation line specified by the shape specification module to correct the captured image,
• the shape specification module of the processor executing
• a classification process for classifying the plurality of line segments into a plurality of clusters,
• a calculation process for calculating an adjustment value corresponding to the distance between a tangent to an ellipse, which represents one of the plurality clusters to which the line segment belongs, at a point at which the ellipse intersects its minor axis, and the line segment for each of the plurality of line segments, and
• an approximation process for specifying the shape approximation line so as to minimize a distance index obtained by adding a distance between a point of intersection where a straight line passing through a specific point and intersects the shape approximation line, and the adjustment value with respect to the plurality of line segments.

An image correction method comprising:

• detecting a plurality of line segments corresponding to a notation on a surface of a document from a captured image obtained by photographing the document
• specifying a shape approximation line that approximates a surface shape of the document from the plurality of line segments, and
• using the specified shape approximation line to correct the captured image,
• the specifying of the shape approximation line being performed so as to minimize a distance index obtained by adding a distance between a point of intersection where a straight line passing through a specific point on the line segment intersects the shape approximation line, and the specific point with respect to the plurality of line segments.

An image correction method comprising:

• detecting a plurality of line segments corresponding to a notation on a surface of a document from a captured image obtained by photographing the document;
• specifying a shape approximation line that approximates a surface shape of the document from the plurality of line segments, and
• using the specified shape approximation line to correct the captured image,
• the specifying of the shape approximation line including
• classifying the plurality of line segments into a plurality of clusters,
• calculating an adjustment value corresponding to the distance between a tangent to an ellipse, which represents one of the plurality clusters to which the line segment belongs, at a point at which the ellipse intersects its minor axis, and the line segment for each of the plurality of line segments, and
• an approximation process for the specifying of the shape approximation line includes an approximation process that minimizes a distance index obtained by adding a distance between a point of intersection where a straight line passing through a specific point and intersects the shape approximation line, and the adjustment value with respect to the plurality of line segments.