private static Message CreateMessage(EmptyPlateRead read, string quality)
{
var bytes = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(read));
var message = new Message(bytes)
{
ContentType = "application/json"
};
message.UserProperties["ReadQuality"] = quality;
return(message);
}
public async Task <Message> Run(
[BlobTrigger("car-images/cameras/{camera}/{name}", Connection = "SECCTRL_CAR_IMAGES")] CloudBlockBlob imageBlob,
string camera,
string name,
ILogger log,
[OrchestrationClient] DurableOrchestrationClient orchestrationClient)
{
log.LogInformation($"Start processing of new image {name} from camera {camera}");
// Store timestamp when image was received in blob storage
var timestamp = imageBlob.Properties.LastModified;
// Read image file from blob storage and convert content to Base64
log.LogInformation("Downloading image data");
var file = new byte[imageBlob.Properties.Length];
await imageBlob.DownloadToByteArrayAsync(file, 0);
// Try to recognize the license plate
log.LogInformation("Starting license plate recognition");
var recognitionResult = await licensePlateRecognizer.RecognizeAsync(file, configuration);
// Move image to archive
log.LogInformation("Moving image to archive folder");
var archiveImageId = Guid.NewGuid().ToString();
var archiveBlob = imageBlob.Container.GetBlockBlobReference($"archive/{archiveImageId}.jpg");
await archiveBlob.StartCopyAsync(imageBlob);
await imageBlob.DeleteAsync();
log.LogInformation("Building plate read result");
if (recognitionResult != null)
{
// We have recognized a license plate
var read = new PlateRead
{
ReadTimestamp = timestamp.Value.Ticks,
CameraID = camera,
LicensePlate = recognitionResult.Plate,
Confidence = recognitionResult.Confidence,
Nationality = recognitionResult.Region,
NationalityConfidence = recognitionResult.RegionConfidence,
ImageID = archiveImageId
};
var readQuality = "low";
if (recognitionResult.Confidence >= 75d && recognitionResult.RegionConfidence >= 25d)
{
readQuality = "high";
}
if (readQuality == "low")
{
var instanceId = await orchestrationClient.StartNewAsync(
"OrchestrateRequestApproval",
new PlateReadApproval
{
Read = read
});
log.LogInformation($"Durable Function Ochestration started: {instanceId}");
}
return(CreateMessage(read, readQuality));
}
else
{
// No license plate found
var read = new EmptyPlateRead
{
ReadTimestamp = timestamp.Value.Ticks,
CameraID = camera,
ImageID = archiveImageId
};
return(CreateMessage(read, "empty"));
}
}