Removing background noise from online audio. How to remove noise from a photo How to remove noise from an audio track

99% of camera users are non-professional photographers. Accordingly, they take all sorts of pictures: light, dark, with noise, red eyes, etc. etc. What doesn't happen!

What if the photo turned out priceless? Photoshop, as always, is in a hurry to help these people.

Imagine the situation: superstars - your idols - have come to your city, you have dreamed of seeing them all your life. And then a miracle happened - you not only managed to buy the last ticket, but you also managed to take a photo with the Legend. But, unfortunately, the person you asked to photograph you seems to have picked up a camera for the first time in his life.

And what happened? The photo is noisy, unclear and blurry. If you find yourself in such a situation or you have photos from which you would like to remove noise, then the information below is for you.

Most often, noise appears when photos are taken at night. So what are some ways to remove digital “noise”?

To test the 2 methods you are about to learn about, let me present you with a test photograph:

Method No. 1. Filter Dust and scratches

Filter Dust and scratches removes a small amount of noise from a photo.

• open the photo in Photoshop
• go to menu Filter - Noise - Dust and scratches...(Filter - Noise - Dust & Scratches)

• play with the settings. Increase the radius parameter. The larger the radius, the softer the photo becomes. It is important to find a compromise - remove noise, but not turn a more or less clear image into a cloudy one.

Method number 2. Filter Reduce noise

To apply this filter:

• open the photo in Photoshop
• go to menu Filter - Noise - Reduce Noise…(Filter - Noise - Reduce Noise)
• play with the settings again. Drag the sliders back and forth and see what happens. Once you like the result, immediately click OK.

As with the filter Dust and scratches This filter also softens the image, but does it a little differently. You can try applying both filters at once.

In addition, if by profession you have to clean photos from various noises every day, then there are plugins Nik Collection Dfine and Topaz DeNoise - they are specially designed to remove noise from photos.

See you in the next lesson!

A microphone is a device that perceives sound waves and converts them into electromagnetic waves. Thanks to its high sensitivity, the microphone can perceive extraneous signals that create strong interference. Noise and interference in a microphone occurs for a number of reasons, which can become a serious problem when recording or transmitting audio. voice messages through the Internet. In order to remove interference in the microphone, you must first find out why it happened.

Background noise in microphone

Microphones are used on stage, for home recording and when communicating via the Internet. Each situation may have its own reasons extraneous noise in the microphone. The following reasons for the appearance of extraneous noise are usually considered:

• Faulty or poor quality microphone
• Irregularities in the connecting cable
• External interference
• Incorrect setting
• Bad software

To get rid of noise in the microphone, you must first check the device itself. A faulty microphone rarely becomes a source of noise. Usually in this case severe distortion occurs during transmission sound signal. Sometimes a bad microphone can be the source of extraneous sound. If the sound vibration receiver is connected via a cable and connector, then to check it it is enough to change the sound channel. In this case, the persistence of noise or distortion indicates a malfunction of the microphone. To record high-quality sound, you should not use cheap devices. They are unreliable and often fail.

How to Suppress Background Microphone Noise

If noise is coming from the microphone, this may be due to a broken ground or common wire. In this case, the low-frequency background will be clearly audible in the speakers. To eliminate this reason, you need to carefully check the cable and restore the broken connection. Microphone noise suppression can be associated with the elimination of poor-quality contact at any point in the amplification path.

Microphones can be remote or built into any technical device. Remote devices, in addition to faults in the connecting cable, may have external reasons causing extraneous noise. One of these reasons may be the oversensitivity of the pre-amp channel when acoustic noise occurs between devices. Feedback. In this case, a pulsating tone will be heard from the speakers, which may change when the position of the sound device is changed. You can remove buzzing and unnecessary noise from the microphone by reducing the level in the audio equipment. In some cases, you can get rid of microphone noise when recording by simply choosing a different installation point for the device. It happens that the sound device perceives external noise or sound from working technical means. Then you can eliminate noise in the microphone by putting a protective screen on the working part of the device. It is usually made of foam rubber and is most often used for outdoor recording.

How to completely remove noise from a microphone

Devices for receiving sound vibrations built into household appliances, may have other causes of noise. Whenever extraneous sounds you need to know how to get rid of background noise in a microphone. Many people who use programs to communicate via the Internet often encounter such problems. Sounds interfere with high-quality sound recording and normal communication. It is possible to remove electrical noise in a microphone, but to do this you need to know the cause of its occurrence. The causes of microphone noise may depend on the following factors:

• Incorrect program settings
• Outdated drivers
• External interference from electronics

In order to check the microphone of a computer or tablet, you need to follow steps that depend on the type and version of the operating system. In older versions of Windows, you need to click right click click on the speaker icon in the lower left corner of the screen and select the “Recording devices” line in the list that appears.

Next, on the microphone icon, you need to right-click to open context menu and select “Properties”. Open the “Listen” item and monitor the operation of the microphone through the speakers of the speaker system. If there is no distortion, extraneous noise is not perceived, but the voice is played back too quietly, then by opening the “Levels” item, you can use the slider to adjust the sensitivity level. If the WEB camera is located far away, the level can be raised to the required value. This is determined by experience.

If there is severe distortion or extraneous noise, you can check the sampling rate. To do this, open the “Advanced” item and on the tab set “1 channel 16 bit 44100 Hz (CD). If after all the actions the strong noise in the microphone does not disappear, then you will probably have to replace it. What to do if noise in the microphone interferes with communication via popular services. To check the correct operation of the audio channel in Skype program you need to do the following:

• Login to the program
• Select the “Tools” section
• Open the “Settings” and “Sound Settings” line

Check the line “Set up the microphone automatically” and in the “Test” mode make sure that the sound playback quality is normal. If the device is humming and the noise in the background of the microphone does not disappear, you should reduce the sensitivity level of the device. The Mail.ru Agent program also has a “Program Settings” item. In the “Voice and Video” tab, select “ Automatic setup sound parameters". If the sensitivity of the device is weak, you can check the box next to “Microphone Gain”. Modes can be configured in manual mode, but auto-tuning eliminates the need to rebuild the device when recording and playback factors change.

If you have installed it on your computer or tablet operating system LINUX family, then the methods for removing noise in the microphone will be slightly different. The reason may lie in a low-quality device. In this case, after checking the audio channel, when other causes are eliminated, it can be replaced. But first you need to use the PulseAudio audio server, which will greatly improve the quality of your audio device.

The audio server has a noise reduction module that operates using the webrtc or speex algorithm. To do this, you need to run the required program as follows: PULSE_PROP=”filter.want=echo-cancel” skype. After this, all communication via Skype will occur without echo and extraneous noise.

The next method is to create constant source and sink with noise suppression across the entire spectrum: load-module-echo-cancel source name=noechosource sinc name=noe chosinc set-default-source noechosource

These lines can be written to /etc/pulse/default.pa in any convenient place so that they are automatically executed every time PulseAudio is launched.

When using this noise reduction option, you should be aware that the module works for both recording and playback, so when working with programs voice communication everything will be fine, and the records high-quality sound may have problems. When noise canceling using the second method, you need to make sure that the program plays noise-canceled audio and not directly to the audio card. When playing music from your computer's built-in player through sinc with noise reduction, the audio files will be played in mono mode and at a sampling rate of 32 kHz, which is very low quality.

How to remove noise from a computer microphone

This defect most often occurs in laptops, where the small size of the device does not allow the device, which is sensitive to sound waves, and some electrical drives to be separated far enough. Most often, noise in the microphone can appear from the operation of the electric drive motor. hard drive whether cooler ventilation. But it happens that some computer operating modes also cause noise in the microphone. If the Windows operating system is set to power saving mode, this may cause noise. In order to make sure of this, you need to enter the “Power Options” settings item and switch it from saving mode to “ High performance" After restarting the computer, the interference may disappear.

Another reason for noise interference may be the connection of incorrect devices to the computer. They are usually connected via USB port and from there they receive food. If the external device is poorly assembled, then power supply interference will get into the headphones. This is not directly related to the microphone, although some external motorized devices can produce vibration that will reach the headphones or acoustic systems via microphone channel. You can verify the presence of an external noise source by sequentially disconnecting all external devices from the ports.

Strong noise in the microphone

Sound playback may not be heard properly if your computer is not connected to the network correctly. The microphone channel is very sensitive to various network interference. They can be created by any household appliance. In addition, low-frequency 50 Hz noise may enter the microphone channel if the device is not grounded. Ideally, the computer should be connected to a grounded Euro socket. You also cannot connect a computer and other household appliances to the same extension cord. A separate extension cord with a mandatory surge protector must be provided for it.

Article content:

Introduction

Not long ago I needed to remove noise from sound. I had never done this before, so I went online to find a way to do this with minimal losses. After 10 minutes of searching, it turned out that all the paths lead to Adobe Audition.

After half an hour of experimentation, I figured out how best to remove the noise. Now I show you enough detailed instructions, how to do it. I will try to collect all the information I found together, summarize it and write it in accessible language. I’ll make a reservation right away that there will only be instructions, and not a description of a bunch of filters for this monster (Audition). Instructions like “There is a problem - here is a solution.” And Audition is essentially the Photoshop of the audio world.

Let's say you recorded sound on a microphone, camera, phone. Often these devices do not differ in particular quality (in terms of sound recording). And there will always be noise - some kind of constant component. And if there is also a generator of additional noise (for example, the hum of coolers in a computer)... Our task is to separate it from speech or music.

There are two options here:

• The audio contains a recording of the atmosphere of a room or street without a useful signal. Those. available noise recording without impurities. For example, let's say you're going to record your friend's guitar playing using a computer microphone. The apartment is quite quiet, there are no neighbors, no one makes noise on the street either (hmm, a rather idealized situation, isn’t it), but a disgusting computer, which is a hundred years old at lunchtime, and besides, has not been cleaned of dust since the day it was born, is treacherous The coolers rattle all over Ivanovo. Well, there are two options: initially record 10-20 seconds before your friend starts playing and the same amount after finishing. In this case, you will have a clearly defined noise that can later be separated. By the way, professional journalists do this whenever possible. And the second option is to clean your computer. Moreover, the second is clearly preferable.
• There is no separate noise recording in the audio. Those. your friend started playing immediately after the recording began, and after finishing, you immediately turned off the microphone. This worst case scenario. The fact is that noise represents a collection of certain frequencies. If there is pure noise, then it is safe to say that these frequencies are noise, garbage and can be removed from the entire track. If, in parallel with the noise, there is some useful signal, then the selected frequencies will no longer be exclusively garbage. And when you remove them throughout the entire track, some part of the useful signal will be lost. Or rather, the music and voice will take on a metallic tint. Therefore, it is better to rewrite such a record. You can also try to find an area where there will be a minimum of useful signal, set less aggressive settings when cleaning noise and come to terms with the metallic echo. Or you can simply record the noise sample in separate file, unless of course you are 1000 km from this place

There is a small original file of 5 seconds in size with obvious background noise. The recording was made using a smartphone voice recorder. And this noise is generated precisely by the phone and is clearly audible at a low volume of the signal source.

Unfortunately, it is not always possible to achieve a clean, noise-free recording on the first try. Sometimes, instead of re-recording, it is best to remove unnecessary noise using software post-processing. There are a number of audio editors that will help you cope with this problem. However, they need to be installed on your computer, plus you will have to spend a lot of time getting to grips with the interface.

To avoid all these problems, it is recommended to use special online services. They cannot fully compete with professional software, but they are very easy to learn. Their functionality should be enough to carry out primitive work with sound.

Removing excess noise online

There is nothing difficult in removing excess noise if it is not very noticeable or is found only in certain short periods of the recording. Otherwise, you will have to spend a lot of time on this. If the recording is very noisy, it is best to re-record rather than try to get rid of the noise.

Unfortunately, there are not many normal resources for cleaning recordings from unnecessary sounds. Let's look in detail at those that we managed to find.

Option 1: Online Audio Noise Reduction

This site is presented in its entirety on English language. However, even basic knowledge of the language will be enough for him comfortable use. Plus, the functionality of the service is not very large, so understanding it will not be very difficult. You can remove excess background noise from your recording as follows:

1. Go to the official website of the service. Pay attention to the line “Input”, here you will need to load the file using special button. You can also select one of the ready-made examples in the “Demo files” field to check the functionality of the service.




2. Windows Explorer will launch. In it you need to select the recording where you want to remove excess noise. After that, click on the “Open” button.




3. In the next line “Noise model type” you need to indicate the type of noise that is present in the recording. To choose the most correct option, you need to have at least basic knowledge of the physics of sound. Let's take a quick look at the available types:
   • "Mean" is the average value. Recommended for use in cases where it is not possible to determine the exact noise model;
   • “Adapted distribution” - distribution of noise across different playback channels, that is, noise is distributed evenly throughout the entire recording;
   • "Autoregressive model" - installation linear dependence noise

   
   

4. Now move on to more detailed settings. You need to determine by ear the approximate duration of a unit of noise to select the correct block size for analysis. Quite often it is not possible to decide immediately, so it is recommended to set the minimum value. Leave the “Enhancement spectral domain” item unchanged. As for the anti-aliasing settings (the last two parameters), set the values ​​there at your discretion. Usually it is enough to extend the slider halfway.




5. If you need to process several tracks, it is recommended to check the box next to “Fix these settings for another file”. This item is responsible for saving the current settings, which will allow them to be applied automatically to other loaded tracks.




6. When you are finished with the settings, use the “Start” button to begin processing. Wait for it to complete; if the recording is small, the processing will complete quickly, but you also need to take into account the speed of your Internet connection. After this, you can listen to the final version of the composition and its original so that you have something to compare with.

Option 2: MP3cutFoxcom

The service that was discussed above is the most worthy in its field, as it allows you to remove noise from the entire composition and has an extensive list of settings. However, it is worth considering that such a need does not always appear. Sometimes it is necessary to remove excess noise only from some temporary section of the composition, which, as a rule, is quieter than other sections. In this case, you can simply trim this part of the audio recording, and for this there are many online services, for example, the same MP3cutFoxcom:

In this article, we looked at online services with which you can get rid of unnecessary noise on audio recordings. However, using them to perform high-quality noise removal is very difficult, since necessary functionality no and you have to be content with what you have.

In the understanding of uninitiated users, audio editing means converting discs to MP3 or FLAC, as well as cutting tracks from a disc image with a CUE markup file. The most advanced “pros” can even make ringtones by cutting out a fragment they like from a musical composition. These are, of course, quite popular actions, but the term “sound processing” has a completely different meaning.

How can I change the sound? First of all, you can influence the frequency characteristics of the audio signal. Frequency correction is akin to a sharpening filter when processing an image - visually the object is made clearer and more legible, but this does not mean that details have been added after editing. When processing audio signal frequencies, approximately the same thing happens. I suppose everyone who wore headphones with a player sometimes felt the need to “tweak the equalizer” to add bass or stretch high frequencies. But what’s interesting is that strongly protruded high frequencies increased noise, which did not decorate the audio track. The reverse procedure—noise suppression using frequency equalization—has a different problem. Along with the noise, a certain spectrum of vocals and music disappears, which leads to the loss of useful information.

Another way to “change” the sound is through the use of effects. In our opinion, such a sound processing technique is justified only when the sound engineer is working on mixing audio material and has a clear idea of ​​what he is doing. Sometimes even a distortion filter can make an audio fragment sound natural. In addition, audio filters often help to hide or veil some defects in the audio track. For example, if there is a strange sound or echo at the end of a recorded instrument part, you can correct this by cutting out or muting the problem area and “immersing” the ending in a smooth echo with a decay effect.

There is a third way to edit digital audio. This is what the sound processing principle in most modern audio editors is based on. For the original recording, a waveform is created - a diagram from which you can visually trace the change in sound amplitude over time. If you open any audio file in a sound editor, such as Sound Forge or Goldwave, you will see that this is the default sound representation option in the program. Modern sound editing packages allow you to make changes to the shape of this “sine wave” - change the shape of the peaks, compress or expand them, remove fragments and modify the nature of the curve. This opens up wide possibilities for the user who sets out to process sound: in the original audio material in the wave form, you can easily find clicks and noise, and then remove them, etc.

Noise is one of the most current problems arising during sound processing. Noise is a natural phenomenon. It is present everywhere and in everything - water gurgles from the tap in the kitchen, cars make noise on the street, computers and printers hum in the office. Accompanies noise and any audio recording, be it a message on an answering machine or musical compositions from an audio disc. Of course, the noise level in all these cases varies, however, it is impossible to completely get rid of it. The nature of noise can be very different - from the buzzing of a drill to the rustling of leaves, so it is impossible to come up with an ideal algorithm that would clear sound from noise. In addition, audio interference is akin to dust and scratches in a photograph - artifacts can be “masked” as the main sound and made less noticeable, or rather inaudible, and can be removed completely.

Most main question The question that confronts users is which tool to choose to combat noise? The choice of a sound processing tool depends on financial preferences. Of course, there are professional applications that use unique audio processing algorithms and cost thousands of dollars. The capabilities of specialized software can be much wider and not limited to noise removal alone. For example, some apps may remove certain sounds from the audio track, such as the occasional noise of a passing car. However, this option can only be afforded by large companies, say, film studios, which have a fairly substantial budget at their disposal. For a user with an average income, a pretty good option is Sound Forge Pro or Adobe Audition. Well, as an economy option, we can offer it, but it must be the latest version, even if it is a beta version. Don't be afraid of the editor's test version. In fact, this program works very stably and is no worse than the official release. In addition, it has some tools that were clearly missing in the previous version.

⇡ Removing noise in pauses between audio tracks in Sound Forge Pro

This professional package for sound processing contains two main tools with which you can “defeat” noise. The first one is called Noise Gate. Imagine an old recording from an audio cassette, where a sharp hissing sound is heard during pauses. Perhaps someone will consider this noise an indispensable attribute of the music of the eighties and will not want to get rid of it when digitizing rare recordings. But if you don’t find any romance in this noise, you can easily suppress it, and without harming the main composition. To do this, a filter is used that removes the signal if it drops to a certain threshold value.

Open the audio file in Sound Forge Pro and select the section of the track that you want to process. Now select Effects and Noise Gate from the program menu. Like most other tools in the application, the filter has several presets and the ability to preview the result with the selected settings.

⇡ Removing background noise in Sound Forge Pro

Sound Forge Pro's second noise reduction tool is the Noise Reduction module, which can be accessed from the Tools menu. The presence of noise usually means that the original information has been lost. The computer, when eliminating random interference, must somehow recover this data. However, by and large, this is impossible, since removing frequencies containing noise leads to the loss of the original sound and the appearance of gurgling artifacts.

When noise is random in nature, it is difficult to describe mathematically. It’s another matter if this noise is caused by cyclic processes, say, electromagnetic oscillations. In this case, you can predict how the waveform should be adjusted to obtain an undistorted signal at the output. To combat these "predictable" types of interference, a background noise capture technique is used. Its essence boils down to the fact that the program records a fragment of “pure” noise and then subtracts it from the audio recording. Such a fragment can be very short, lasting less than a second.

Sony Noise Reduction allows you to either automatically capture noise or do it manually. In manual suppression mode, the module generates a picture of the frequency spectrum and marks control points on it that determine the nature of noise suppression. Those data on the graph that are located above the envelope will be left unchanged. And to those located below it, attenuation will be applied. Accordingly, when manually moving control points up, the noise suppression effect will be stronger, and vice versa.

Sony Noise Reduction can use one of four noise reduction algorithms, which are called Mode 0, Mode 1, Mode 2 and Mode 3.

The default mode is Mode 2, which works well for most situations. But the developers recommend always checking how the program copes with noise removal in all possible modes, and choose the best result.

• Mode 0 is generally suitable for removing noise from low level amplitudes. However, its use increases the likelihood of distorting artifacts;
• Mode 1 is similar to Mode 0, but is less likely to cause artifacts. On the other hand, it removes less noise;
• Mode 3 is the most gentle noise reduction mode, in which the likelihood of sound defects is minimized.

⇡ Removing clicks from audio recordings in Sound Forge Pro

Usually music recording, transferred digitally from a vinyl record, is accompanied by crackles and clicks. In this case, it is not enough to use a noise profile, since the record crack is unpredictable. Sound Forge Pro has a special tool for eliminating the most common noise when digitizing audio recordings. To call it, run the command “Tools → Audio Restoration”.

In addition to selecting the noise threshold and other background noise suppression options, this tool also gives you the ability to adjust click suppression. The Click Removal Amount slider is responsible for this. By default, its value is set in the middle and is optimal for most records. Moving the slider to the right will remove more clicks, but it may also accidentally remove elements of the main audio, such as the drum sound.

⇡ Removing background noise in Audacity

To remove noise in free editor Audacity can use the same techniques as with Sound Forge. For example, the “Noise Removal” module, written by Dominic Mazzoni, in fact, one of the authors of Audacity, is suitable. To use this filter, you need to take a few seconds to create a noise profile, and then choose Effects → Noise Removal.

After this, you need to click on the “Create noise model” button and, having selected the entire audio fragment to be processed, call this filter again. Now in the settings window you can select the strength of noise reduction (Noise reduction), adjust the filter sensitivity, specify the smoothing frequency and attack time, which characterizes the filter’s reaction to the appearance of noise.

Sometimes the noise profile method does not work, or the recording is so dense that there is nowhere to get this profile from. In this case, you can resort to this trick. To obtain a profile, you simply need to make an additional recording under the same conditions in which the edited material was recorded. Next, the profile can be taken from new entry. Unfortunately, it is not always possible to recreate the initial conditions, so this technique is not suitable for all cases.

⇡ Removing a nasty squeak in Audacity

If you know the tools of sound editors well, you can eliminate interference using the sound editor tools in a comprehensive manner, and not just with one “noise reduction” filter. Suppose you are faced with another type of noise - a constant squeak at a certain frequency. This type of interference can occur, for example, due to strong interference from radio equipment. In this case, the principle of cutting out the frequency band that contains unwanted noise is used.

First of all, to do this you need to perform a frequency analysis of the track. To get such a graph in Audacity, run the command “Analysis → Build spectrum graph”.

Now study the diagram carefully - frequency noise on soundtrack will be visible as a protruding hump. Hover your cursor over this area to find out the exact frequency of this peak. Remember this value. Now select the entire track and select “Effects → Nyquist Query” from the program menu.

In the window that appears, write something like this:

• (vector (notch2 (aref s 0) 6230 50) (notch2 (aref s 1) 6230 50)) for a stereo track,
• (notch2 s 6230 50) - if you have one audio track.

The number 6230 is the frequency at which interference is heard. The number 50 is a setting that you may need to experiment with to ensure that the cut frequency doesn't create too noticeable a dip in the frequency spectrum of the audio recording. You can verify that noise has been removed either by looking at the newly generated frequency spectrum or simply by ear.

⇡ Conclusion

Using high-quality equipment - expensive microphones, high-quality amplifiers, etc. - undoubtedly helps reduce noise. But in cases where it is impossible to influence the quality of the recording, it is worth remembering about digital audio processing. And even if it is not possible to completely get rid of third-party interference, in many cases the recording will become more pleasant to the ear. Therefore, if you set out to restore old recordings from a reel-to-reel or cassette recorder, be sure to try all possible options to eliminate noise, because, as you know, there is no limit to perfection.