Chord judging apparatus and chord judging method

Patent metadata

Field	Value
Publication number	US-10062368-B2
Application number	US-201715677656-A
Country	US
Kind code	B2
Filing date	Aug 15, 2017
Priority date	Sep 28, 2016
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A chord judging method performed by a processor to judge chords of a musical piece, in which the processor estimates plural chord candidates of each of plural parts specified in the musical piece; calculates connection costs, each of which is defined between the chord candidates of adjacent parts of the musical piece; obtains total sums of the connection costs between the chord candidates along plural routes through the musical piece; and selects a route from among the plural routes, which route shows a less total sum of the connection costs of the chord candidates, thereby outputting an appropriate chord candidate of each of the parts along the found route of the musical piece.

First claim

What is claimed is:

1. A chord judging method performed by a processor to judge chords of a musical piece whose data is stored in a memory, wherein the processor executes processes of:
estimating plural chord candidates of each of plural parts specified in the musical piece;
calculating connection costs, each of which is defined between the chord candidates of adjacent parts of the musical piece;
obtaining total sums of the connection costs between the chord candidates along plural routes through the musical piece; and
selecting a route from among the plural routes, which route shows a less total sum of the connection costs of the chord candidates, thereby outputting an appropriate chord candidate of each of the parts along the found route of the musical piece.

2. The chord judging method according to claim 1 , wherein
the connection cost is defined as showing a less value when modulation in chord between the adjacent parts of the musical piece is more natural;
a route which connects the chord candidates of the adjacent parts with each other is defined as a partial route;
a route which connects a first part of the musical piece to a second part of the musical piece is defined as a connection route; and
the processor executes processes of
calculating the connection costs of the plural partial routes of the musical piece;
obtaining a total sum of the connection costs of plural partial routes included in each of the plural connection routes;
selecting a connection route from among the plural connection routes, which connection route shows a less total sum of the connection costs of the plural partial routes; and
outputting an optimum chord candidate of each of the parts along the selected connection route.

3. The chord judging method according to claim 1 , wherein
the processor executes processes of
selecting a connection route which shows the minimum total sum of the connection costs of the partial routes, from among plural connection routes consisting of plural connected partial routes; and
outputting an optimum chord candidate of each of the parts along the selected connection route.

4. The chord judging method according to claim 1 , wherein
the processor executes processes of
calculating the connection cost of the chord candidates of the adjacent parts in accordance with musical modulation rules of a chord route and a chord type between continuous chord candidates.

5. The chord judging method according to claim 1 , wherein
the processor executes processes of
calculating the connection costs between the chord candidates of the next preceding part and the chord candidate of the current part with respect to each chord candidate of the current part as the parts of the musical piece sequentially progress from the leading part;
adding the calculated connection costs to a total minimum cost which has been calculated with respect to the chord candidates of the next preceding part, thereby calculating a transferring cost defined when the chord candidates of the next preceding part are transferred to the chord candidate of the current part;
finding the chord candidate showing the minimum transferring cost among the chord candidates of the next preceding part as an optimum route from the chord candidate of the next preceding part to the chord candidate of the current part; and
obtaining the minimum transferring cost as the total minimum cost of the chord candidate of the current part.

6. The chord judging method according to claim 5 , wherein
the processor executes processes of
calculating total minimum costs of chord candidates of the tail part of the plural parts of the musical piece;
selecting a chord candidate showing the minimum total minimum cost among the chord candidates of the tail part as an optimum chord candidate of the tail part; and
sequentially going back, with the optimum chord candidate of the tail part as a starting point, the routes of the optimum chord candidate of the next preceding part from the tail part to the head part of the musical piece, thereby selecting the optimum chord candidate to each of the parts along the musical piece.

7. The chord judging method according to claim 1 , wherein
the processor uses Dijkstra's algorithm in selecting the route showing a less total sum of the connection costs from among the plural routes.

8. A chord judging apparatus for judging chords of a musical piece, having a processor and a memory for storing data of the musical piece, wherein the processor
estimates plural chord candidates of each of plural parts specified in the musical piece;
calculates connection costs, each of which is defined between chord candidates of adjacent parts of the musical piece;
obtains total sums of the connection costs between the chord candidates along plural routes through the musical piece; and
selects a route from among the plural routes, which route shows a less total sum of the connection costs of the chord candidates, thereby outputting an appropriate chord candidate of each of the parts along the found route of the musical piece.

9. The chord judging apparatus according to claim 8 , wherein
the connection cost is defined as showing a less value when modulation in chord between the adjacent parts of the musical piece is more natural;
a route which connects the chord candidates of the adjacent parts with each other is defined as a partial route;
a route which connects a first part of the musical piece to a second part of the musical piece is defined as a connection route; and
the processor calculates the connection costs of the plural partial routes of the musical piece;
obtains a total sum of the connection costs of plural partial routes included in each of the plural connection routes;
selects a connection route from among the plural connection routes, which connection route shows a less total sum of the connection costs of the plural partial routes; and
outputs an optimum chord candidate of each of the parts along the selected connection route.

10. The chord judging apparatus according to claim 8 , wherein
the processor selects a connection route which shows the minimum total sum of the connection costs of the partial routes, from among plural connection routes consisting of plural connected partial routes; and
outputs an optimum chord candidate of each of the parts along the selected connection route.

11. The chord judging apparatus according to claim 8 , wherein
the processor calculates the connection cost of the chord candidates of the adjacent parts in accordance with musical modulation rules of a chord route and a chord type between continuous chord candidates.

12. The chord judging apparatus according to claim 8 , wherein
the processor calculates the connection costs between the chord candidates of the next preceding part and the chord candidate of the current part with respect to each chord candidate of the current part as the parts of the musical piece sequentially progress from the leading part;
adds the calculated connection costs to a total minimum cost which has been calculated with respect to the chord candidates of the next preceding part, thereby calculating a transferring cost defined when the chord candidates of the next preceding part are transferred to the chord candidate of the current part;
finds the chord candidate showing the minimum transferring cost among the chord candidates of the next preceding part as an optimum route from the chord candidate of the next preceding part to the chord candidate of the current part; and
obtains the minimum transferring cost as the total minimum cost of the chord candidate of the current part.

1

Assignees

• Casio Computer Co Ltd

Inventors

• Minamitaka Junichi

Classifications

• G10H1/383 Primary

  Chord detection and/or recognition, e.g. for correction, or automatic bass generation · CPC title

• G10H2210/576

  Chord progression · CPC title

• G10H2210/081

  for automatic key or tonality recognition, e.g. using musical rules or a knowledge base · CPC title

• G10H2220/036

  Chord indicators, e.g. displaying note fingering when several notes are to be played simultaneously as a chord · CPC title

• G10H2210/571

  Chords; Chord sequences · CPC title