poor image quality

[jarvis10211]

Camera view quality is very bad & blurry therefore barcode detection not working properly. How to increase image qualty or resolution?

[hjam40]

Platform?? Are you talking about preview, photo, snaphot, video? In the Camera property (CameraInfo class) you have a property AvailableResolutions with the camera supported resolutions

[jarvis10211]

bad image quality in barcode scan camera viewfinder at both IOS and android

[Maryusz]

I use this library to scan qr codes too, and I have the same issue I suppose. Using the code from the documentation when a tab shows the preview of the qr code it gets really strange effect on the camera, like the camera starts with a very low and blurry resolution.

        {
            cameraView.Camera = cameraView.Cameras.First();
            MainThread.BeginInvokeOnMainThread(async () =>
            {
                try
                {
                    if (cameraView != null && await cameraView.StartCameraAsync() == CameraResult.Success)
                    {
                        await Task.Delay(500);
                        cameraView.BarCodeOptions = new Camera.MAUI.ZXingHelper.BarcodeDecodeOptions
                        {
                            AutoRotate = true,
                            PossibleFormats = { ZXing.BarcodeFormat.QR_CODE },
                            ReadMultipleCodes = false,
                            TryHarder = true,
                            TryInverted = true
                        };

                        cameraView.BarCodeDetectionFrameRate = 10;
                        cameraView.BarCodeDetectionMaxThreads = 2;
                        cameraView.ControlBarcodeResultDuplicate = true;
                        cameraView.BarCodeDetectionEnabled = true;
                    }
                }
                catch (Exception ex)
                {
                    Debug.WriteLine(ex.Message);

                }
            });
        }

When I however 'restart' the view, resolution it's right.

protected override void OnAppearing()
    {
        base.OnAppearing();

        MainThread.BeginInvokeOnMainThread(async () =>
        {
            try
            {
                await cameraView.StartCameraAsync();
            }
            catch (Exception ex)
            {
                Debug.WriteLine(ex.Message);
            }

        });
    }

Now I tried to select a resolution with Size(x, y) and if I remember well, the issue persist. The difference is that if a Resolution is selected it is better performant (if you have a 4k camera on the phone and you don't select a resolution, it becomes hot from processing the images because it analyzes images in the highest resolution.).

[hjam40]

Hi,

The behavior is different between platforms. When you call StartCameraAsync with a Size parameter, this resolution is used when you call TakePhotoAsync (in all platforms) and for the preview resolution (only in iOS and Windows). In Android, the plugging sets the preview resolution depending of CameraView control size due a performance issue.

Seeing your photos, the problem sames to be due the camera focus. You could call the ForceAutoFocus method.

[manuelgroo]

I have tried calling the ForceAutoFocus method but I'm getting the same poor quality in my camera, do you have any other idea to solve this?

[Maryusz]

I added too the ForceAutoFocus method call, but actually the problem persists. It seems that at a first start, the camera takes a low resolution, if I restart the camera (in my app on appearing, the camera is restarted) it works fine.

[hjam40]

Hi,

It same to be a problem in some android devices and I can't do anything to solve it. On Android I set the AutoFocus on when you start the camera (and when you restart it is the same method...)

[Vetleskrett]

I had the same problem. For me the problem was that I called cameraView.StartCameraAsync() before I had set cameraView.Camera. cameraView.Camera was null, but CameraResult was still CameraResult.Success.

ContentPage_Appearing() was called first, then cameraView_CamerasLoaded() was called. This resulted in low resolution for some reason.

    private void ContentPage_Appearing(object sender, EventArgs e)
    {
        MainThread.BeginInvokeOnMainThread(async () =>
        {
            await cameraView.StopCameraAsync();
            await cameraView.StartCameraAsync();
        });
    }

    private void cameraView_CamerasLoaded(object sender, EventArgs e)
    {
        MainThread.BeginInvokeOnMainThread(async () =>
        {
            if (cameraView.Cameras.Count > 0)
            {
                cameraView.Camera = cameraView.Cameras.First();

                await cameraView.StopCameraAsync();
                await cameraView.StartCameraAsync();
            }
        });
    }

I simply solved it by adding a if check. Also, it only worked if I stopped before starting for some reason.

    private void ContentPage_Appearing(object sender, EventArgs e)
    {
        MainThread.BeginInvokeOnMainThread(async () =>
        {
            if (cameraView.Camera is not null)
            {
                await cameraView.StopCameraAsync();
                await cameraView.StartCameraAsync();
            }
        });
    }

[Maryusz]

I'll try the same approach tomorrow, thank for the suggestion @Vetleskrett 👍

[kennykanp]

It's strange that this happens. In my case, I'm currently working around the issue like this:

await cameraView.StopCameraAsync();
await cameraView.StartCameraAsync();
await Task.Delay(TimeSpan.FromSeconds(3));
if (!cameraView.IsFocused)
{
    await cameraView.StopCameraAsync();
    await cameraView.StartCameraAsync(cameraView.Camera.AvailableResolutions.OrderByDescending(size => size.Width * size.Height).FirstOrDefault());
    cameraView.ForceAutoFocus();
}

This workaround seems to resolve the problem, but it would be great to find a more permanent solution.

[Robula]

Same quality issue if starting the camera too early, I am working around this by adding Task.Delay(1); before I start the camera.

Without workaround:

With workaround:

Here is my code:

public partial class CameraPage : ContentPage, IAsyncDisposable
{
    public CameraPage()
    {
        InitializeComponent();

        CameraView.CamerasLoaded += CameraView_CamerasLoaded;
        CameraView.BarcodeDetected += CameraViewOnBarcodeDetected;
        CameraView.Loaded += CameraViewOnLoaded;
    }

    private async void CameraViewOnLoaded(object? sender, EventArgs e)
    {
        CameraView.Loaded -= CameraViewOnLoaded;
        await Task.Delay(1);  // Workaround
        await CameraView.StartCameraAsync();
    }

    // Omitted
}

[UnreachableCode]

@Vetleskrett's workaround worked for me. I don't think it's a good idea to rely on Task.Delay because you can't be sure how different devices are going to handle time related code.

[mdjavedakhtar]

i am still having the same issue on android the available resolutions are showing 0 image is too low resolution !!

[DanielWooldridge1]

Has there been any updates on this issue?