Abstract:
Provided is a sound processing device including: a sound input unit for dividing an input sound into predetermined time units; a sound processing unit for encoding the input sound thus divided; a noise detecting unit; and an output control unit for replacing encoded data on the input sound with silent data according to detection results of the noise detecting unit. Also provided is an input sound processing method including: encoding an input sound; judging whether or not the input sound contains a noise; and replacing a noise portion contained in the encoded input sound with silent data.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a sound processing device and a method therefor, and more particularly to a sound processing device for canceling an input noise, a method therefor, and a computer program product therefor.  
         [0003]     2. Description of the Related Art  
         [0004]     In an electronic device such as a microphone having an audio input unit, various noises alone or along with a desired audio may be inputted into the audio input unit. The various noises include a noise generated due to an operation of the electronic device. In a portable communication device such as a cellular phone, a microphone is disposed in the vicinity of a key operation unit. Therefore, a sound generated due to a key operation may be inputted into the microphone and sent to a communication counterpart.  
         [0005]     For example, JP 3,420,831 B and JP 60-173600 A each disclose a method of suppressing and canceling a noise inputted through a microphone. Other known methods include a method of extracting a noise from an inputted sound and generating a sound wave having an inverse phase to the noise, thereby suppressing the noise.  
         [0006]     However, know noise canceling processings increase a processing time required for a sound data processing. In other words, the sound data processing delays by a time required for the noise canceling processing.  
       SUMMARY OF THE INVENTION  
       [0007]     It is an object of the present invention to provide a sound processing device capable of reducing a processing time required for a sound data processing accompanied by a noise canceling processing, and a method therefor.  
         [0008]     In order to achieve the above object, according to an aspect of the present invention, there is provided a sound processing device including: input sound dividing means for dividing an input sound into predetermined time units; input sound encoding means for encoding the input sound thus divided; noise detecting means; and output control means for replacing encoded data on the input sound with silent data according to detection results of the noise detecting means.  
         [0009]     According to another aspect of the present invention, there is provided a sound processing device including: a sound input unit for dividing an input sound into predetermined time units; a sound processing unit for encoding the input sound thus divided; a noise detecting unit; and an output control unit for replacing encoded data on the input sound with silent data according to detection results of the noise detecting unit.  
         [0010]     According to further another aspect of the present invention, there is provided an input sound processing method including: encoding an input sound; judging whether or not the input sound contains a noise; and replacing a noise portion contained in the encoded input sound with silent data.  
         [0011]     According to still another aspect of the present invention, there is provided a computer program product in a computer readable medium for use in a sound processing device, the computer program product including the steps of: encoding an input sound; judging whether or not the input sound contains a noise; and replacing a noise portion contained in the encoded input sound with silent data.  
         [0012]     According to the present invention as described above, even execution of the noise canceling processing does not increase a time required for a sound data processing, unlike conventional techniques. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     The above and other objects, features and advantages of the present invention will become apparent form the following detailed description when taken with the accompanying drawings in which:  
         [0014]      FIG. 1  is a block diagram of an example in which a sound processing device according to an embodiment of the present invention is applied to a portable communication terminal;  
         [0015]      FIG. 2  shows processing times for processings within a sound processing device according to the embodiment shown in  FIG. 1 ;  
         [0016]      FIG. 3  is a block diagram of a sound processing device according to another embodiment of the present invention;  
         [0017]      FIG. 4  is a block diagram of a sound processing device according to further another embodiment of the present invention;  
         [0018]      FIG. 5  is a block diagram of a sound processing device according to still another embodiment of the present invention; and  
         [0019]      FIG. 6  shows a configurational example in which a sound processing device according to the present invention is applied to an audio recording device. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     Herein after, description will be made on a sound processing device according to preferred embodiments of the present invention.  FIG. 1  shows an example in which a sound processing device  1  according to an exemplary embodiment of the present invention is applied to a portable communication terminal such as a cellular phone. The sound processing device  1  includes a sound input unit  10 , a sound processing unit  20 , a key operation detecting unit  30 , and an output control unit  40 . A communication unit  50  and a key input unit  60  are structural components of the portable communication terminal. The sound input unit  10  divides input audio data into predetermined time units called frames (processing  1 ) and sends the frames to the sound processing unit  20  (processing  2 ). The sound processing unit  20  encodes the frames received from the sound input unit  10  (processing  3 ) and sends the frames to the output control unit  40  (processing  4 ). The key operation detecting unit  30  detects a key operation through the key input unit  60  (processing  5 ) and notifies the output control unit  40  of the detection results (processing  6 ). In other words, the key operation detecting unit  30  is a kind of noise detecting unit. The sound processing device  1  recognizes that a noise is being inputted to the sound input unit  10  due to the key operation. Based on the detection results sent from the key operation detecting unit  30 , the output control unit  40  selects an encoded data frame received from the sound processing unit  20  or a silent frame encoded in advance by the output control unit  40  (processing  7 ). To be specific, when the key operation detecting unit  30  detects the key operation, the output control unit  40  replaces the encoded data frame with the silent frame and sends the silent frame to the communication unit  50 . When the key operation detecting unit  30  does not detect the key operation, the output control unit  40  sends the encoded data frame to the communication unit  50 .  
         [0021]      FIG. 2  shows processing times for processings within the sound processing device  1 . When an input key (that is, key input unit  60 ) of the portable communication terminal is operated, a noise such as a key click sound is inputted to the sound input unit  10  at time t 1 . The key operation detecting unit  30  electrically detects an operation such as key depression (processing  5 ). The key operation detecting unit  30  detects the key operation at time t 2 , or after a lapse of a predetermined time from the noise generation. However, a time required for the processings (processings  5  and  6 ) at the key operation detecting unit  30  is generally shorter than a time required for the processings (processings  1  to  4 ) at the sound input unit  10  and the sound processing unit  20 . Accordingly, an input sound encoding processing and a noise (i.e. key operation sound) detecting processing are performed in parallel. The encoded data frame and the key operation detection results reach the output control unit  40  substantially at the same time. Therefore, the time required for processing an input sound is prevented from being longer due to the noise detection/canceling processing. In addition, it is unnecessary to detect a noise generated due to key depression from among input sound signals, thereby realizing a simple sound processing device and a method therefor.  
         [0022]      FIG. 3  shows a sound processing device according to another exemplary embodiment of the present invention. The sound processing device  1  has a noise detecting unit  70  replacing the key operation detecting unit  30 . The noise detecting unit  70  performs noise detection from an input sound through a known sound processing (processing  5 ′). Similarly to the above-mentioned embodiment, the sound input unit  10  converts an input sound into frames and sends the frames to the sound processing unit  20  and the noise detecting unit  70 . Accordingly, the noise detecting processing and the sound encoding processing are performed in parallel and independently of each other. Those processings require substantially the same time. Upon reception of noise detection from the noise detecting unit  70 , similarly to the above-mentioned embodiment, the output control unit  40  replaces an encoded data frame (noise frame) of the input sound with a silent frame. Also in this exemplary embodiment, the time required for processing an input sound is prevented from being longer due to the noise detection processing.  
         [0023]      FIG. 4  shows a sound processing device according to further another exemplary embodiment of the present invention. In the sound processing device  1  shown in  FIG. 4 , a noise memory unit  80  is added to the sound processing device  1  shown in  FIG. 3 . The noise memory unit  80  holds data on various key click sounds generated through an input key. By referencing the data, the noise detecting unit  70  can detect a noise with ease and in a short time. The noise memory unit  80  can hold data on a noise detected by the noise detecting unit  70 . In addition, it is possible to collect various key click sounds by operating keys in advance and to store the sounds in the noise memory unit  80 . Also in this embodiment, processings  1  to  4 ,  5 ′,  6 , and  7  are the same as those of the embodiments shown in  FIGS. 1 and 3 . The noise memory unit  80  allows the sound processing device  1  to further reduce the time required for a sound data processing.  
         [0024]      FIG. 5  shows a sound processing device according to still another exemplary embodiment. Upon detection of an input key (key input unit  60 ) operation and upon detection of a noise among input sound data sent from the sound input unit  10 , the noise detecting unit  70  sends noise data to the noise memory unit  80 . Also in this embodiment, processings  1  to  4 ,  5 ′,  6 , and  7  are the same as those of the embodiments shown in  FIGS. 1 and 3 . By referencing the noise data within the noise memory unit  80 , the noise detecting unit  70  can detect a noise with ease. In this embodiment, the noise memory unit  80  automatically accumulates data on various noises simultaneously to the operation of the sound processing device  1 . This exemplary embodiment eliminates the necessity of a particular operation of causing the noise memory unit  80  to store the noise data therein.  
         [0025]      FIG. 6  shows an example in which the above-mentioned sound processing device  1  is applied to an audio recording device. The output control unit  40  of the sound processing device  1  shown in  FIG. 1  outputs sound data to a memory unit  90  rather than to the communication unit  50 . In this case, noise data (such as a key click sound) among the sound data is replaced with silent data. Also in this embodiment, processings  1  to  4 ,  5 ′,  6 , and  7  are the same as those of the above-mentioned embodiments.  
         [0026]     The sound processing device  1  described above may include a control unit (not shown). The control unit may incorporate therein at least one of the sound input unit  10 , the sound processing unit  20 , the key operation detecting unit  30 , the output control unit  40 , the noise detecting unit  70 , and the noise memory unit  80 .  
         [0027]     The present invention can be applied to a cellular phone, a radio communication device, an audio recording device, and the like.  
         [0028]     While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by the present invention is not limited to those specific embodiments. On the contrary, it is intended to include all alternatives, modifications, and equivalents as can be included within the spirit and scope of the following claims.  
         [0029]     Further, it is the inventor&#39;s intent to retain all equivalents of the claimed invention even if the claims are amended during prosecution.