public static async void ScanFirstCameraForQrCode(
Action <Result> resultCallback,
TimeSpan timeout)
{
Result result = null;
// Note - I keep this frame processor around which means keeping the
// underlying MediaCapture around because when I didn't keep it
// around I ended up with a crash in Windows.Media.dll related
// to disposing of the MediaCapture.
// So...this isn't what I wanted but it seems to work better :-(
if (frameProcessor == null)
{
var mediaFrameSourceFinder = new MediaFrameSourceFinder();
// We want a source of media frame groups which contains a color video
// preview (and we'll take the first one).
var populated = await mediaFrameSourceFinder.PopulateAsync(
MediaFrameSourceFinder.ColorVideoPreviewFilter,
MediaFrameSourceFinder.FirstOrDefault);
if (populated)
{
// We'll take the first video capture device.
var videoCaptureDevice =
await VideoCaptureDeviceFinder.FindFirstOrDefaultAsync();
if (videoCaptureDevice != null)
{
// Make a processor which will pull frames from the camera and run
// ZXing over them to look for QR codes.
frameProcessor = new QrCaptureFrameProcessor(
mediaFrameSourceFinder,
videoCaptureDevice,
MediaEncodingSubtypes.Bgra8);
// Remember to ask for auto-focus on the video capture device.
frameProcessor.SetVideoDeviceControllerInitialiser(
vd => vd.Focus.TrySetAuto(true));
}
}
}
if (frameProcessor != null)
{
// Process frames for up to 30 seconds to see if we get any QR codes...
await frameProcessor.ProcessFramesAsync(timeout);
// See what result we got.
result = frameProcessor.QrZxingResult;
}
// Call back with whatever result we got.
resultCallback(result);
}
public static async void ScanFirstCameraForQrCode(
Action <Result> resultCallback,
TimeSpan timeout)
{
Result result = null;
var mediaFrameSourceFinder = new MediaFrameSourceFinder();
// We want a source of media frame groups which contains a color video
// preview (and we'll take the first one).
var populated = await mediaFrameSourceFinder.PopulateAsync(
MediaFrameSourceFinder.ColorVideoPreviewFilter,
MediaFrameSourceFinder.FirstOrDefault);
if (populated)
{
// We'll take the first video capture device.
var videoCaptureDevice =
await VideoCaptureDeviceFinder.FindFirstOrDefaultAsync();
if (videoCaptureDevice != null)
{
// Make a processor which will pull frames from the camera and run
// ZXing over them to look for QR codes.
var frameProcessor = new QrCaptureFrameProcessor(
mediaFrameSourceFinder,
videoCaptureDevice,
MediaEncodingSubtypes.Bgra8);
// Remember to ask for auto-focus on the video capture device.
frameProcessor.SetVideoDeviceControllerInitialiser(
vd => vd.Focus.TrySetAuto(true));
// Process frames for up to 30 seconds to see if we get any QR codes...
await frameProcessor.ProcessFramesAsync(timeout);
// See what result we got.
result = frameProcessor.QrZxingResult;
}
}
// Call back with whatever result we got.
resultCallback(result);
}
async void OnStartOcrAsync(object sender, RoutedEventArgs e)
{
this.txtResult.Text = "Starting...";
var videoCaptureDeviceFinder = new VideoCaptureDeviceFinder();
#if HOLOLENS
await videoCaptureDeviceFinder.InitialiseAsync(
devices => devices.First());
#else
await videoCaptureDeviceFinder.InitialiseAsync(
devices => devices.Where(device => device.EnclosureLocation.Panel == Windows.Devices.Enumeration.Panel.Front).Single());
#endif // HOLOLENS
if (videoCaptureDeviceFinder.HasDevice)
{
var mediaFrameSourceFinder = new MediaFrameSourceFinder(videoCaptureDeviceFinder);
#if HOLOLENS
var filters = new FilterSet()
.Append(MediaFrameSourceFinder.VideoPreviewFilter, MediaFrameSourceFinder.ColorFilter)
.Append(m => ((m.Width == 1280) && (m.FrameRate >= 30)));
#else
var filters = new FilterSet()
.Append(MediaFrameSourceFinder.VideoPreviewFilter, MediaFrameSourceFinder.ColorFilter)
.Append(m => ((m.Width == 1920) && (m.FrameRate >= 30)));
#endif // HOLOLENS
await mediaFrameSourceFinder.InitialiseAsync(
matchingMediaSourceInfos => matchingMediaSourceInfos.First(), filters);
var ocrScanner = new DeviceAndCloudOcrScanner(
mediaFrameSourceFinder, new Regex(IP_ADDRESS_REGEX));
this.txtResult.Text = "Matching with the local device camera...";
using (var matchedResult = await ocrScanner.MatchOnDeviceAsync(TimeSpan.FromSeconds(10)))
{
if (matchedResult.ResultType == OcrMatchResult.Succeeded)
{
// We found what we were looking for, finished!
this.txtResult.Text = $"Found result {matchedResult.MatchedText}";
}
else if (matchedResult.ResultType == OcrMatchResult.TimedOutCloudCallAvailable)
{
// We haven't matched but we have got a frame with at least some text in
// it which the on-device OCR hasn't matched.
// So...we can try the cloud.
this.txtResult.Text = $"Calling cloud...";
var result = await ocrScanner.MatchOnCloudAsync(
AZURE_TEXT_RECOGNITION_API,
AZURE_COMPUTER_VISION_KEY,
matchedResult,
TimeSpan.FromSeconds(5),
TimeSpan.FromSeconds(30));
if (result.ResultType == OcrMatchResult.Succeeded)
{
this.txtResult.Text = $"Found result {result.MatchedText}";
}
else
{
this.txtResult.Text = $"Didn't work {result.ResultType}";
}
}
else
{
this.txtResult.Text = $"Result returned {matchedResult.ResultType}";
}
}
}
}
