public Reading Analyze(Mat input)
{
var resized = input.ResizePreserveAspectRatio(maxSize: _settings.InputAnalysisMaxSize);
var grayScale = resized.Image.CvtColor(ColorConversionCodes.BGR2GRAY);
var noiseReduced = grayScale.Erode(new Mat()).Dilate(new Mat());
var meterNumberRectangles = DetectMeterNumbers(noiseReduced);
if (!meterNumberRectangles.Any())
{
return(new Reading(""));
}
Mat[] croppedImages;
if (_settings.DarkSectors)
{
croppedImages = meterNumberRectangles.Select(r =>
{
var rect = new Rect(r.Position.X, r.Position.Y, r.Width, r.Height);
return(new Mat(noiseReduced, rect)
.Threshold(0, 255, ThresholdTypes.Otsu)
.Erode(new Mat())
.ResizePreserveAspectRatio(_settings.DarkSectorsSeparateMeterNumbersResizeMaxSize).Image);
}).ToArray();
}
else
{
croppedImages = meterNumberRectangles.Select(r =>
{
var rect = new Rect(r.Position.X, r.Position.Y, r.Width, r.Height);
return(new Mat(noiseReduced, rect)
.AdaptiveThreshold(255, AdaptiveThresholdTypes.GaussianC, ThresholdTypes.BinaryInv, _settings.LightSectorsAdaptiveThresholdBlockSize, _settings.LightSectorsAdaptiveThresholdC)
.ResizePreserveAspectRatio(_settings.LightSectorsSeparateMeterNumbersResizeMaxSize).Image);
}).ToArray();
croppedImages = croppedImages.Select(i =>
{
var rect = new BlobDetector().GetLargestBlob(i);
return(new Mat(i, rect));
}).ToArray();
}
var resizedCroppedNumbers = croppedImages.ResizeToAverageHeight();
var combinedNumbers = resizedCroppedNumbers.Skip(1)
.Aggregate(croppedImages[0], (a, b) => a.CombineImages(b), r => r);
var numbers = combinedNumbers.WidenEdges(10);
if (!_settings.DarkSectors)
{
Cv2.BitwiseNot(numbers, numbers);
}
var reading = new Reading(InsertDecimal(_stringExtractor.GetStringFromImage(numbers)),
GetScaledRectangles(resized.OriginalScale, meterNumberRectangles));
return(reading);
}
private Rectangle[] DetectMeterNumbers(Mat image)
{
var blobDetector = new BlobDetector();
var threshold = image.AdaptiveThreshold(255,
AdaptiveThresholdTypes.GaussianC,
_settings.DarkSectors ? ThresholdTypes.Binary : ThresholdTypes.BinaryInv,
_settings.NumbersDetectionAdaptiveThresholdBlockSize,
_settings.NumbersDetectionAdaptiveThresholdC);
return(blobDetector.DetectMeterNumbers(threshold).ToArray());
}
