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Scanner improvements - added the logic from original zxing android project to set the best camera settings #789

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Scanner improvements - added the logic from original zxing android project to set the best camera settings #789

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c609818
Update CameraAnalyzer.cs
vkalyanapu Nov 14, 2018
a250ef2
Update CameraController.cs
vkalyanapu Nov 14, 2018
1ae0e82
Update CameraAnalyzer.cs
vkalyanapu Nov 14, 2018
5dd202e
Update CameraController.cs
vkalyanapu Nov 14, 2018
b8c8f6b
Merge branch 'dev' into master
Redth Dec 13, 2018
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251 changes: 239 additions & 12 deletions Source/ZXing.Net.Mobile.Android/CameraAccess/CameraController.cs
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
using System;
using System;
using System.Collections.Generic;
using System.Linq;
using Android.Content;
Expand All @@ -9,11 +9,15 @@
using Android.Views;
using ApxLabs.FastAndroidCamera;
using Camera = Android.Hardware.Camera;
using Android.Util;

namespace ZXing.Mobile.CameraAccess
{
public class CameraController
{
private const float MAX_EXPOSURE_COMPENSATION = 1.5f;
private const float MIN_EXPOSURE_COMPENSATION = 0.0f;
private const int AREA_PER_1000 = 300;
private readonly Context _context;
private readonly ISurfaceHolder _holder;
private readonly SurfaceView _surfaceView;
Expand Down Expand Up @@ -75,9 +79,10 @@ public void SetupCamera()
var previewSize = previewParameters.PreviewSize;
var bitsPerPixel = ImageFormat.GetBitsPerPixel(previewParameters.PreviewFormat);


int bufferSize = (previewSize.Width * previewSize.Height * bitsPerPixel) / 8;
const int NUM_PREVIEW_BUFFERS = 5;

Log.Debug(MobileBarcodeScanner.TAG, $"bitsPerPixed={bitsPerPixel}; bufferSize={bufferSize}");
const int NUM_PREVIEW_BUFFERS = 5;
for (uint i = 0; i < NUM_PREVIEW_BUFFERS; ++i)
{
using (var buffer = new FastJavaByteArray(bufferSize))
Expand All @@ -92,7 +97,7 @@ public void SetupCamera()
}
catch (Exception ex)
{
Android.Util.Log.Debug(MobileBarcodeScanner.TAG, ex.ToString());
Log.Debug(MobileBarcodeScanner.TAG, ex.ToString());
return;
}
finally
Expand All @@ -112,6 +117,20 @@ public void AutoFocus()
AutoFocus(0, 0, false);
}


/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
public void LowLightMode(bool on)
{
var parameters = Camera?.GetParameters();
if (parameters != null)
{
SetBestExposure(parameters, on);
Camera.SetParameters(parameters);
}
}

public void AutoFocus(int x, int y)
{
// The bounds for focus areas are actually -1000 to 1000
Expand Down Expand Up @@ -150,7 +169,7 @@ public void ShutdownCamera()
}
catch (Exception e)
{
Android.Util.Log.Error(MobileBarcodeScanner.TAG, e.ToString());
Log.Error(MobileBarcodeScanner.TAG, e.ToString());
}

PerformanceCounter.Stop(perf, "Shutdown camera took {0}ms");
Expand Down Expand Up @@ -182,7 +201,7 @@ private void OpenCamera()
Camera.GetCameraInfo(i, camInfo);
if (camInfo.Facing == whichCamera)
{
Android.Util.Log.Debug(MobileBarcodeScanner.TAG,
Log.Debug(MobileBarcodeScanner.TAG,
"Found " + whichCamera + " Camera, opening...");
Camera = Camera.Open(i);
_cameraId = i;
Expand All @@ -193,7 +212,7 @@ private void OpenCamera()

if (!found)
{
Android.Util.Log.Debug(MobileBarcodeScanner.TAG,
Log.Debug(MobileBarcodeScanner.TAG,
"Finding " + whichCamera + " camera failed, opening camera 0...");
Camera = Camera.Open(0);
_cameraId = 0;
Expand Down Expand Up @@ -232,29 +251,65 @@ private void ApplyCameraSettings()
var supportedFocusModes = parameters.SupportedFocusModes;
if (_scannerHost.ScanningOptions.DisableAutofocus)
parameters.FocusMode = Camera.Parameters.FocusModeFixed;
else if (supportedFocusModes.Contains(Camera.Parameters.FocusModeAuto))
parameters.FocusMode = Camera.Parameters.FocusModeAuto;
else if (Build.VERSION.SdkInt >= BuildVersionCodes.IceCreamSandwich &&
supportedFocusModes.Contains(Camera.Parameters.FocusModeContinuousPicture))
parameters.FocusMode = Camera.Parameters.FocusModeContinuousPicture;
else if (supportedFocusModes.Contains(Camera.Parameters.FocusModeContinuousVideo))
parameters.FocusMode = Camera.Parameters.FocusModeContinuousVideo;
else if (supportedFocusModes.Contains(Camera.Parameters.FocusModeAuto))
parameters.FocusMode = Camera.Parameters.FocusModeAuto;
else if (supportedFocusModes.Contains(Camera.Parameters.FocusModeFixed))
parameters.FocusMode = Camera.Parameters.FocusModeFixed;
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Changing order of focus selection has completely broke scanner autofocus on my device (Vernee thor).



Log.Debug(MobileBarcodeScanner.TAG,
$"FocusMode ={parameters.FocusMode}");
var selectedFps = parameters.SupportedPreviewFpsRange.FirstOrDefault();
if (selectedFps != null)
{
Log.Debug(MobileBarcodeScanner.TAG,
$"Old Selected fps Min:{selectedFps[0]}, Max {selectedFps[1]}");
// This will make sure we select a range with the lowest minimum FPS
// and maximum FPS which still has the lowest minimum
// This should help maximize performance / support for hardware
//foreach (var fpsRange in parameters.SupportedPreviewFpsRange)
//{
// if (fpsRange[0] < selectedFps[0] && fpsRange[1] >= selectedFps[1])
// selectedFps = fpsRange;
//}

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
foreach (var fpsRange in parameters.SupportedPreviewFpsRange)
{
if (fpsRange[0] <= selectedFps[0] && fpsRange[1] > selectedFps[1])
if (fpsRange[1] > selectedFps[1] || fpsRange[1] == selectedFps[1] && fpsRange[0] < selectedFps[0])
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Can you walk through the logic here please? I'm thinking it might help to use some more parenthesis and add some comments in the code here to explain it.

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I just copied the suggestion from - #395 (comment)

I agree that the line 306 needs an improvement -
Basically the issue with old line - 253 is that it is selecting the bottom value in the range.

New line should be something like =>
if (fpsRange[1] >= selectedFps[1] && fpsRange[0] < selectedFps[0])

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or

if (fpsRange[0] < selectedFps[0] && fpsRange[1] >= selectedFps[1])

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Yeah this is kind of interesting. Probably this issue is right and should pick something with a range from the lowest to the highest.

I think your idea for the logic is probably ok:

if (fpsRange[1] >= selectedFps[1] && fpsRange[0] < selectedFps[0])

This should loop through and keep looking for the widest range... In the case of #395 this logic would end up choosing the 15000,30000 which I think is a good result.

selectedFps = fpsRange;
}

Log.Debug(MobileBarcodeScanner.TAG,
$" Setting Selected fps to Min:{selectedFps[0]}, Max {selectedFps[1]}");

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
parameters.SetPreviewFpsRange(selectedFps[0], selectedFps[1]);
}

if (_scannerHost.ScanningOptions.LowLightMode == true)
SetBestExposure(parameters, parameters.FlashMode != Camera.Parameters.FlashModeOn);

/*
* Improvements based on zxing android library
* - Setting default auto focus areas instead of single focus point
* - Setting Barcode scene mode if available for the device
* - Set metering to improve lighting/ exposure in the focused area (i.e., rectangular focus area in the center)
* - **** Imp ==> In UI project a layout should be created to mask other areas except the center rectangular area.
* To inform the user that app/ camera only scans the center rectangular area of the device.
*/
SetDefaultFocusArea(parameters);
SetBarcodeSceneMode(parameters);
SetMetering(parameters);

CameraResolution resolution = null;
var supportedPreviewSizes = parameters.SupportedPreviewSizes;
Expand Down Expand Up @@ -302,7 +357,7 @@ private void ApplyCameraSettings()
// Hopefully a resolution was selected at some point
if (resolution != null)
{
Android.Util.Log.Debug(MobileBarcodeScanner.TAG,
Log.Debug(MobileBarcodeScanner.TAG,
"Selected Resolution: " + resolution.Width + "x" + resolution.Height);
parameters.SetPreviewSize(resolution.Width, resolution.Height);
}
Expand All @@ -312,6 +367,177 @@ private void ApplyCameraSettings()
SetCameraDisplayOrientation();
}

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
private void SetBestExposure(Camera.Parameters parameters, bool lowLight)
{
int minExposure = parameters.MinExposureCompensation;
int maxExposure = parameters.MaxExposureCompensation;
float step = parameters.ExposureCompensationStep;
if ((minExposure != 0 || maxExposure != 0) && step > 0.0f)
{
// Set low when light is on
float targetCompensation = MAX_EXPOSURE_COMPENSATION;
int compensationSteps = (int)(targetCompensation / step);
float actualCompensation = step * compensationSteps;
// Clamp value:
compensationSteps = lowLight ? Math.Max(Math.Min(compensationSteps, maxExposure), minExposure) : (int)MIN_EXPOSURE_COMPENSATION;
if (parameters.ExposureCompensation == compensationSteps)
{
Log.Debug(MobileBarcodeScanner.TAG, "Exposure compensation already set to " + compensationSteps + " / " + actualCompensation);
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "Setting exposure compensation to " + compensationSteps + " / " + actualCompensation);
parameters.ExposureCompensation = compensationSteps;
}
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "Camera does not support exposure compensation");
}
}

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
private void SetDefaultFocusArea(Camera.Parameters parameters)
{
if (parameters?.MaxNumFocusAreas > 0)
{
List<Camera.Area> middleArea = BuildMiddleArea(AREA_PER_1000);
Log.Debug(MobileBarcodeScanner.TAG, "Setting focus area to : " + middleArea.Select(f => f.Rect.FlattenToString()).Aggregate((first, next) => first + "; " + next));
parameters.FocusAreas = middleArea;
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "Device does not support focus areas");
}
}

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
private void SetMetering(Camera.Parameters parameters)
{
if (parameters?.MaxNumMeteringAreas > 0)
{
List<Camera.Area> middleArea = BuildMiddleArea(AREA_PER_1000);
Log.Debug(MobileBarcodeScanner.TAG, "Setting metering areas: " + middleArea.Select(f => f.Rect.FlattenToString()).Aggregate((first, next) => first + "; " + next));
parameters.MeteringAreas = middleArea;
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "Device does not support metering areas");
}
}

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
private List<Camera.Area> BuildMiddleArea(int areaPer1000)
{
return new List<Camera.Area>()
{
new Camera.Area(new Rect(-areaPer1000, -areaPer1000, areaPer1000, areaPer1000), 1)
};
}

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
private void SetVideoStabilization(Camera.Parameters parameters)
{
if (parameters.IsVideoStabilizationSupported)
{
if (parameters.VideoStabilization)
{
Log.Debug(MobileBarcodeScanner.TAG, "Video stabilization already enabled");
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "Enabling video stabilization...");
parameters.VideoStabilization = true;
}
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "This device does not support video stabilization");
}
}

/// <summary>
///Scanning Improvement, VK 10/2018
/// </summary>
private void SetBarcodeSceneMode(Camera.Parameters parameters)
{
if (parameters.SceneMode == Camera.Parameters.SceneModeBarcode)
{
Log.Debug(MobileBarcodeScanner.TAG, "Barcode scene mode already set");
return;
}
var supportedSceneModes = parameters.SupportedSceneModes;
if (supportedSceneModes?.Contains(Camera.Parameters.SceneModeBarcode) == true)
{
Log.Debug(MobileBarcodeScanner.TAG, $"Previous SceneMode={parameters.SceneMode}");
parameters.SceneMode = Camera.Parameters.SceneModeBarcode;
Log.Debug(MobileBarcodeScanner.TAG, "Barcode scene mode is set");
}

}

private void SetZoom(Camera.Parameters parameters, double targetZoomRatio)
{
if (parameters.IsZoomSupported)
{
var zoom = IndexOfClosestZoom(parameters, targetZoomRatio);
if (zoom == null)
{
return;
}
if (parameters.Zoom == zoom)
{
Log.Debug(MobileBarcodeScanner.TAG, "Zoom is already set to " + zoom);
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "Setting zoom to " + zoom);
parameters.Zoom = (int)zoom;
}
}
else
{
Log.Debug(MobileBarcodeScanner.TAG, "Zoom is not supported");
}
}

private int? IndexOfClosestZoom(Camera.Parameters parameters, double targetZoomRatio)
{
var ratios = parameters.ZoomRatios.ToList();
Log.Debug(MobileBarcodeScanner.TAG, "Zoom ratios: " + ratios);
int maxZoom = parameters.MaxZoom;
if (ratios == null || ratios.Count == 0 || ratios.Count != maxZoom + 1)
{
Log.Debug(MobileBarcodeScanner.TAG, "Invalid zoom ratios!");
return null;
}
double target100 = 100.0 * targetZoomRatio;
double smallestDiff = Double.PositiveInfinity;
int closestIndex = 0;
for (int i = 0; i < ratios.Count; i++)
{
double diff = Math.Abs(ratios[i]?.LongValue() ?? 0 - target100);
if (diff < smallestDiff)
{
smallestDiff = diff;
closestIndex = i;
}
}
Log.Debug(MobileBarcodeScanner.TAG, "Chose zoom ratio of " + ((ratios[closestIndex]?.LongValue() ?? 0) / 100.0));
return closestIndex;
}

private void AutoFocus(int x, int y, bool useCoordinates)
{
if (Camera == null) return;
Expand Down Expand Up @@ -360,6 +586,7 @@ private void AutoFocus(int x, int y, bool useCoordinates)
{
new Camera.Area(new Rect(x, y, x + 20, y + 20), 1000)
};
Android.Util.Log.Debug(MobileBarcodeScanner.TAG, $"AutoFocus Area =(x={x}, y={y}, right = {x + 20}, bottom ={y + 20})");
Camera.SetParameters(cameraParams);
}

Expand Down Expand Up @@ -432,4 +659,4 @@ private int GetCameraDisplayOrientation()
return correctedDegrees;
}
}
}
}