Background Art Since personal computers started to be spread in the 1980's, computer technology, performance and environment have been rapidly developed. In the 1990's, Internet was rapidly spread to various departments of companies and personal life. Therefore, use of computers is very important in every field throughout the world in the 21st century.

Such computer technology has been applied to the field of music.

Music instrument digital interface (MIDI) is a representative computer music technology of synthesizing and storing human voices or sounds of musical instruments. MIDI uses information about the kind of instrument, pitch, note strength, and the start and end of a note to express music and allows MIDI data to be operated so that various types of music can be reproduced. Accordingly, MIDI has been widely used for musical operations such as composition, recording, and musical editing. With the wide spread of MIDI, MIDI instruments for outputting MIDI data are increasingly necessary. In order to satisfy this necessity, various types of MIDI instruments have been developed. However, most of the MIDI instruments are very expensive, and it is difficult to find MIDI instruments except for digital pianos and MIDI guitars.

In the meantime, with the development of music recognition technology in the 21st century, it is possible to detect the pitch of the sound of an instrument or the pitch of a human voice in real time and then detect MIDI data from the pitch. However, methods of detecting

pitch from sound and detecting MIDI data from the pitch have not been widely spread, and thus musicians accustomed to different types of acoustic instruments need to use special MIDI instruments, such as digital pianos, in order to utilize MIDI music.

Disclosure of the Invention The present invention provides a portable music instrument digital interface (MIDI) converting apparatus for converting sound, which is detected from the performance of various types of acoustic instruments and vocalists'voices, into MIDI data so that as well as players used to acoustic instruments, even vocalists who do not play the musical instruments can satisfactorily utilize MIDI music without using special MIDI instruments.

According to an aspect of the present invention, there is provided a portable MIDI converting apparatus including a sound input unit, which receives sound performed outside and outputs a digital sound signal corresponding to the received sound; a signal processing unit, which operates in an operating mode determined in accordance with an external control signal, receives the digital sound signal from the sound input unit, detects pitch values from the digital sound signal, and generates MIDI data from the detected pitch values ; a housing, which contains the sound input unit and the signal processing unit therewithin and is structured to be portable ; an operating signal input unit, which is provided on a predetermined position in an outside of the housing to be easily operated by a user and provides user interface for allowing the user to select the operating mode of the signal processing unit; a display unit, which provided at a predetermined position in the outside of the housing and displays the operating mode of the signal processing unit and user convenience information; a control unit, which controls operation of the signal processing unit in accordance with the operating mode selected through the operating signal input unit; and a data

interface unit, which transmits the MIDI data output from the signal processing unit to an external apparatus.

Preferably, the signal processing unit includes a pitch detector, which receives the digital sound signal from the sound input unit, analyzes the digital sound signal into frequency components in units of frames, and detects pitch values included in each frame; a MIDI converter, which receives the pitch values of each frame from the pitch detector and converts each pitch value into MIDI data based on predetermined MIDI conversion information; and an output unit, which outputs the MIDI data.

Brief Description of the Drawings FIG. 1 is a schematic diagram of a portable music instrument digital interface (MIDI) converting apparatus according to a first embodiment of the present invention.

FIG. 1A is a schematic diagram of a portable MIDI converting apparatus according to a second embodiment of the present invention.

FIG. 2 is a schematic diagram of a portable MIDI converting apparatus according to a third embodiment of the present invention.

FIG. 2A is a schematic diagram of a portable MIDI converting apparatus according to a fourth embodiment of the present invention.

FIG. 3 is a schematic block diagram of an embodiment of the inner structure of a portable MIDI converting apparatus according to the present invention.

FIG. 4 is a diagram showing an example of the results of pitch detection when a portable MIDI converting apparatus according to the present invention is operated in an octave change mode.

FIG. 5 is a diagram showing an example of the results of pitch detection when a portable MIDI converting apparatus according to the present invention is operated in a sustain mode and a volume control mode.

Best mode for carrying out the Invention Hereinafter, preferred embodiments of a portable music instrument digital interface (MIDI) converting apparatus according to the present invention will be described in detail with reference to the attached drawings.

FIG. 1 is a schematic diagram of a portable MIDI converting apparatus according to a first embodiment of the present invention.

Referring to FIG. 1, a portable MIDI converting apparatus 100 according to the first embodiment of the present invention is implemented by a type of microphone and includes a MIDI connector 150 at the end of a data transmission line 140 extending from a microphone-shaped housing 110.

A sound input unit (not shown) and a signal processing unit (not shown) are provided within the housing 110. The sound input unit receives sound performed outside and outputs a digital sound signal corresponding to the received sound. The signal processing unit operates in an operating mode determined in accordance with an external control signal, detects MIDI data from the digital sound signal received from the sound input unit, and outputs the MIDI data.

In addition, operating signal input units 121 through 123, which provide user interface allowing a user to select an operating mode of the signal processing unit, and a display unit 130, which displays the operating mode of the signal processing unit and"user convenience information", are provided at predetermined positions in the outside of the housing 110. The"user convenience information"indicates information, such as present time, date, and power supply state, which other portable apparatuses usually provide for user's convenience.

In the meantime, the operating signal input units 121 through 123 are located to be easily operated by a user and implemented by a type of button or switch so that the user can easily select a function, such as an octave change mode, an instrument selection mode, a volume control

mode, a sustain mode, or a data output format selection mode, which is used during conversion of real performance sound into MIDI data.

In the first embodiment shown in FIG. 1, the operating signal input units 121 through 123 are provided in the handle portion of the portable MIDI converting apparatus 100 and are implemented by a mode selection button 123 for allowing a user to select an operating mode, a selection button 121 for sequentially displaying configuration values for an operating mode selected by the user's operation of the mode selection button 123, and a setup button 122 for setting a currently displayed value as a configuration value for the current operating mode.

Accordingly, the user can easily select a desired function with his/her hand holding the portable MIDI converting apparatus 100. In other words, in the first embodiment shown in FIG. 1, the user can select a desired operating mode by operating the mode selection button 123, make the display unit 130 to display configuration values for the selected operating mode by operating the selection button 121, and set a configuration value of the operating mode by operating the setup button 122.

The display unit 130 displays the operating state of the signal processing unit, which is determined by the user's operation of the operating signal input units 121 through 123. In the first embodiment shown in FIG. 1, the display unit 130 is provided in the handle portion of the portable MIDI converting apparatus 100. Referring to an enlarged view of the display unit 130 in FIG. 1, the display unit 130 displays the ON or OFF state of a sustain function, a current configuration value set for volume, a selected octave, the name of a selected instrument, and the output format of MIDI data.

For example, as shown in FIG. 1, in the case where five operating modes, i. e. , a sustain mode, a volume control mode, an octave change mode, an instrument selection mode, and an output format selection mode, are displayed on the display unit 130, when a user operates the

mode selection button 123, the sustain mode, the volume control mode, the octave change mode, the instrument selection mode, and the output format selection mode are sequentially selected. Here, the user repeatedly operates the mode selection button 123 until a desired operating mode is selected. In FIG. 1, the octave change mode is selected. More specifically, an arrow displayed on the left of the name of an operating mode moves one mode to another in response to the operation of the mode selection button 123 and informs the user of the selection of each operating mode.

If the desired operating mode is selected, the user can make the display unit 130 to display configuration values selectable for the current operating mode by operating the selection button 121. Referring to FIG.

1, the selection button 121 is composed of two buttons so that the user can increase or decrease a configuration value. For example, when a configuration value 0 is displayed in the octave change mode, if the user operates the left selection button 121, the configuration value sequentially decreases by one, like-1--2-.... Conversely, if the user operates the right selection button 121, the configuration value sequentially increases by one, like +1- +2-.... If the user selects "-1"in the octave change mode, MIDI data corresponding to pitch one octave lower than input pitch is output. If the user selects"+1"in the octave change mode, MIDI data corresponding to pitch one octave higher than input pitch is output. When the sustain mode is selected, since only ON and OFF exist as configuration values, ON and OFF are alternately displayed in response to the operation of the selection button 121, regardless of the position of the selection button 121. When the volume control mode is selected, if the right selection button 121 is operated, increasing values for volume are sequentially displayed. If the left selection button 121 is operated, decreasing values for volume are sequentially displayed.

If the user operates the setup button 122 to select the displayed configuration value, a configuration value for the current operating mode is finally set. In FIG. 1, the configuration value 0 is set for the octave change mode.

In the meantime, operating mode selection information determined for the signal processing unit through the operating signal input units 121 through 123 is transmitted to a control unit (not shown) provided within the housing 110. The control unit controls the operation of the signal processing unit according to the operating mode selection information.

The result of the operation of the signal processing unit authorized by the control unit, that is, MIDI data, is transmitted to an external apparatus through a data interface unit composed of the data transmission line 140 and the MIDI connector 150. The MIDI connector 150 may be substituted with a universal serial bus (USB) connector.

The external apparatus is special equipment for detecting various kinds of sound information and score information using MIDI data. The external apparatus is beyond the scope of the present invention, and thus a detailed description thereof will be omitted.

FIG. 1A is a schematic diagram of a portable MIDI converting apparatus according to a second embodiment of the present invention.

The portable MIDI converting apparatus 100 shown in FIG. 1A includes a data transmission antenna 160 as a data interface for transmitting MIDI data to an external apparatus.

Although the data interface for interfacing the portable MIDI converting apparatus 100 with an external apparatus can be implemented in a wired structure, as shown in FIG. 1, it can be implemented in a wireless structure, as shown in FIG. 1A. In the wireless structure, it will be apparent that the external apparatus should be provided with a receiver for receiving data transmitted through the data transmission antenna 160.

FIG. 2 is a schematic diagram of a portable MIDI converting apparatus 200 according to a third embodiment of the present invention.

Referring to FIG. 2, the portable MIDI converting apparatus 200 according to the third embodiment is implemented by a small-sized device such as a mini-cassette tape player and includes a port 270, into which an audio jack 11 extending from an external microphone 10 is inserted, in order to receive a sound signal transmitted from the microphone 10.

The portable MIDI converting apparatus 200 shown in FIG. 2 also includes a sound input unit (not shown), which receives sound performed outside and outputs a digital sound signal corresponding to the received sound, and a signal processing unit (not shown), which operates in an operating mode determined in accordance with an external control signal, detects MIDI data from the digital sound signal received from the sound input unit, and outputs the MIDI data, within a housing 210. If the microphone 10 is a digital microphone, which outputs a sound signal in the form of a digital signal, the sound input unit does not need a separate analog-to-digital (A/D) converter. However, if the microphone 10 is an analog microphone, which outputs a sound signal in the form of an analog signal, the sound input unit needs a separate A/D converter.

The portable MIDI converting apparatus 200 shown in FIG. 2 also includes operating signal input units 221 through 223 for determining the operating state of the signal processing unit and a display unit 230 displaying the operating state of the signal processing unit, which are located at predetermined positions in the outside of the housing 210. In particular, the operating signal input units 221 through 223 are positioned such that a user can easily operate them.

The functions and operations of the operating signal input units 221 through 223 and the display unit 230 shown in FIG. 2 are similar to those of the operating signal input units 121 through 123 and the display unit 130 shown in FIG. 1, and thus descriptions thereof will be omitted.

While the portable MIDI converting apparatus 200 shown in FIG. 2 transmits MIDI data to an external apparatus through a data interface unit composed of a data transmission line 240 and a MIDI connector 250, a portable MIDI converting apparatus 200 according to a fourth embodiment of the present invention shown in FIG. 2A includes a data transmission antenna 260 at a predetermined position on a housing 210.

In the third and fourth embodiments of the present invention shown in FIGS. 2 and 2A, a sound signal is transmitted from the microphone 10 through a wire. However, when a wireless microphone is used, it will be apparent that the portable MIDI converting apparatus 200 can be provided with a reception antenna for receiving a sound signal wirelessly transmitted from the wireless microphone.

In the meantime, a power supply unit for supplying power for operating a portable MIDI converting apparatus has not been described in the embodiments shown in FIGS. 1 through 2A, but a portable MIDI converting apparatus according to the present invention is supplied with power in the same manner as usual portable apparatuses using a battery, an adaptor, or the like. Power supply is not the main subject of the present invention, and a method of supplying power to a portable apparatus using a battery or adaptor has widely known. Thus, a description thereof will be omitted.

FIG. 3 is a schematic block diagram of an embodiment of the inner structure of a portable MIDI converting apparatus according to the present invention. Referring to FIG. 3, the embodiment of a portable MIDI converting apparatus according to the present invention includes a sound input unit 300, an analog-to-digital (A/D) converter 400, a signal processing unit 500, and a control unit 600. The signal processing unit 500 includes a pitch detector 510, a MIDI converter 520, and an output unit 530. The operation of the signal processing unit 500 is controlled by the control unit 600, which generates and outputs control signals for controlling the operation of the signal processing unit 500 in response to

operating signals input through operating signal input units (121 through 123 in FIG. 1 or 221 through 223 in FIG. 2).

The sound input unit 300 receives sound performed outside. The A/D converter 400 converts an analog sound signal received from the sound input unit 300 into a digital sound signal. The signal processing unit 500 analyzes the digital sound signal received from the A/D converter 400 and outputs MIDI data. When a sound signal received through the sound input unit 300 is a digital sound signal, the A/D converter 400 may be omitted. However, it is assumed that a sound signal received through the sound input unit 300 shown in FIG. 3 is an analog sound signal.

The pitch detector 510 receives the digital sound signal from the A/D converter 400, analyzes the digital sound signal into frequency components in units of frames, and detects pitch values included in each frame. In order to detect pitch values included in each frame from the digital sound signal, various techniques widely known can be used. A pitch detection method, which is disclosed in Korean Patent Application Nos. 2001-45565,2001-47777, and 2002-02460 filed by this applicant in advance, can also be used. Thus, a detailed description of pitch detection will be omitted.

In the meantime, when a sustain mode is set to be ON by a user's operation, that is, when a function of automatically outputting sound other than performance sound is selected, the pitch detector 510 continuously outputs pitch values, which were set as automatic output pitch in advance, during a predetermined period of time. Here, a pitch value set as automatic output pitch may be a previous pitch value or a pitch value for a particular sound and can be selected at a user's option.

The MIDI converter 520 receives the pitch values of each frame from the pitch detector 510. The MIDI converter 520 converts each pitch value into MIDI data based on predetermined MIDI conversion information and simultaneously sets a volume value of MIDI data based

on the strength of sound of each frame. When a user has selected a volume control mode and set a desired volume value, the MIDI converter 520 changes the volume value of MIDI data based on the volume value set by the user.

In addition, the MIDI converter 520 manages MIDI conversion information regarding to pitch values in each musical scale in order to refer it for converting a pitch value into MIDI data. The MIDI conversion information can be expressed as a table or a function. Accordingly, the MIDI converter 520 converts each pitch value into MIDI data based on the MIDI conversion information of each musical scale. A specific example of MIDI conversion by the MIDI converter 520 is disclosed in Korean Patent Application No. 2002-02407 filed by this applicant in advance. When a user has selected an octave change mode and set a desired octave, the MIDI converter 520 changes the octave of MIDI data based on octave information, which has been selected in order to perform octave change, and predetermined octave change information.

The output unit 530 outputs MIDI data, which is the result of processing performed by the signal processing unit 500, to the outside in a predetermined format.

The sound input unit 300, the A/D converter 400, the signal processing unit 500, and the control unit 600 shown in FIG. 3 are installed within a housing of a portable MIDI converting apparatus of the present invention, and thus they are not shown in FIGS. 1 through 2A.

FIG. 4 is a diagram showing an example of the results of pitch detection when a portable MIDI converting apparatus according to the present invention is operated in an octave change mode. In the example shown in FIG. 4, a pitch value detected from externally input sound is raised two octaves. More specifically, the singing voice of an adult man is received and raised two octaves, and thus trumpet MIDI sound is generated. Referring to FIG. 4, an actually detected pitch value is 48.10 (C3). A value 24 corresponding to two octaves is added

to the value 48.10 according to an octave change function, and thus the MIDI converter 520 outputs a sound corresponding to a pitch value 72.10 (C5) with respect to a sound corresponding to a pitch value 48. 10 (C3). In the same manner, a sound corresponding to a pitch value 48.15 (C3) is converted into a sound corresponding to a pitch value 72.15 (C5), a sound corresponding to a pitch value 49.90 (D3) is converted into a sound corresponding to a pitch value 73.90 (D5), and a sound corresponding to a pitch value 50.05 (D3) is converted into a sound corresponding to a pitch value 74.05 (D5). Accordingly, sound in a musical range that an adult man's voice cannot reach can be easily generated using the octave change function.

FIG. 5 is a diagram showing an example of the results of pitch detection when a portable MIDI converting apparatus according to the present invention is operated in a sustain mode and a volume control mode. More specifically, in the example shown in FIG. 5, an adult woman singing a song was out of breath after vocalizing a sound corresponding to a pitch value 65.0 at a strength corresponding to a MIDI velocity 60 and thus set the sustain mode to ON and selected a volume value in the volume control mode. In particular, in the example shown in FIG. 5, a pitch value automatically output in the sustain mode was set to a previous pitch value. Here, the MIDI velocity has a value in a range of 0-127. A midi velocity 0 indicates no sound, and a midi velocity 127 indicates a loudest sound. Referring to FIG. 5, since the pitch value 65.0 had been output at the MIDI velocity 60 when the sustain mode was set to ON, pitch values output from the pitch detector 510 after the sustain mode was set to ON (below the bold line in FIG. 5) are sustained at 65.0. In the example shown in FIG. 5, with the setup of ON sustain mode, volume was set to gradually decrease using a volume control button, so output sound is gradually diminished from a volume value 60 to 50,40, and 30 as time lapses.

The above description just concerns embodiments of the present invention. The present invention is not restricted to the above embodiments, and various modifications can be made thereto within the scope defined by the attached claims. For example, the shape and structure of each member specified in the embodiments can be changed.

Industrial Applicability As described above, a portable MIDI converting apparatus according to the present invention converts sound made by an acoustic instrument or human voice into MIDI data by utilizing a microphone and thus allows MIDI music operation, which is possible only with digital pianos or MIDI guitars in conventional technology, to be applied to all kinds of acoustic instruments and human voices. Accordingly, musicians playing acoustic instruments, such as a flute, a short bamboo flute, and a trumpet for which MIDI instruments do not exist, can perform various MIDI music operations, such as composition and arrangement, by easily inputting MIDI music to a MIDI sequence using a portable MIDI converting apparatus according to the present invention, without using digital pianos. In other words, the present invention allows existing acoustic instruments to be directly utilized in MIDI operations so that a user can easily perform MIDI operations with acoustic instruments, such as flutes or bamboo flutes for which MIDI instruments cannot be manufactured due to economical and technical problems.

In addition, the present invention allows even a beginner who cannot play musical instruments at all to easily produce his/her own MIDI music.