I am using a biometrics SDK. And I converted the headers to delphi to consume the dll.
It looks something like this:
const
{VrBio_EventType}
VRBIO_CAPTURE_EVENT_UNPLUG = $001; {Fingerprint scanner unplugged from the computer.}
VRBIO_CAPTURE_EVENT_PLUG = $002; {Fingerprint scanner plugged on the computer.}
VRBIO_CAPTURE_EVENT_REMOVED = $004; {Finger removed from the fingerprint scanner.}
VRBIO_CAPTURE_EVENT_PLACED = $008; {Finger placed on the fingerprint scanner.}
VRBIO_CAPTURE_EVENT_IMAGE_FRAME = $10; {A fingerprint frame was captured on the fingerprint scanner.}
VRBIO_CAPTURE_EVENT_IMAGE_CAPTURED = $020; {A fingerprint image was captured on the fingerprint scanner.}
VRBIO_CAPTURE_EVENT_FAKE_FINGER_DETECTED = $400; {A false finger has been detected on the sensor}
VRBIO_CAPTURE_EVENT_FAKE_FINGER_REMOVED = $800; {A false finger has been removed from the sensor}
type
(* Stores the parameters of the ISO 19794-4 image format. #see VGetReaderProperties #see VrBio_ReaderProperty
typedef struct
{
/** #see VrBio_ISO197944CompressionMode*/
int compressionMode;
/** #see VrBio_ISO197944ImpressionType*/
int impressionType;
/** #see VrBio_ISO197944FingerPosition*/
int fingerPosition;
}VrBio_ISO197944Parameters;
*)
PISO197944Parameters = ^TISO197944Parameters;
TISO197944Parameters = record
compressionMode: Integer; { #see VrBio_ISO197944CompressionMode}
impressionType: Integer; { #see VrBio_ISO197944ImpressionType}
fingerPosition: Integer; { #see VrBio_ISO197944FingerPosition}
end;
(* Represents a biometric image. #see VrBio_CaptureEventCallback \ref VSyncCapture
struct VrBio_BiometricImage
{
/** Image width.*/
int width;
/**Image height*/
int height;
/**Image resolution in dpi. For the obsolete functions, use pixels/cm.*/
int resolution;
/**Number of channels in the image. Fingerprint images should always be grayscale, so this value is always 1.*/
int channels;
/**Biometric modality.
* Always use VRBIO_BIOMETRIC_MODALITY_FINGERPRINT.
* \ref VrBio_BiometricModality.
*/
int biometricModality;
/**Scanner type.
* \ref VrBio_ScannerType.
*/
int scannerType;
/**Formato de imagem: Formato da imagem.
*\ ref VrBio_ImageFormat.*/
int imageFormat;
/**Size of the buffer*/
int bufferSize;
/**Compression rate. Valid for images that allow compression.
* \ref VrBio_CompressionRate
*/
int compressionRate;
/**Quality of the fingerprint image.
* \ref VrBio_FingerQuality
*/
int fingerQuality;
/** Only valid if the image if imageFormat is \ref VrBio_ImageFormat::VRBIO_IMAGEFORMAT_ISO19794_4
*\ref VrBio_ISO197944Parameters
*/
VrBio_ISO197944Parameters* ISO197944_parameters;
/** Buffer storing the pixels of the image.
The position(x,y,c) of a pixel is y*width*channels+x*channels+c.
*/
unsigned char* buffer;
/**Reserved for future use*/
void* reserved;
};
typedef struct VrBio_BiometricImage VrBio_BiometricImage;
*)
PBiometricImage = ^TBiometricImage;
TBiometricImage = record
width: Integer; { Image width. }
height: Integer; { Image height }
resolution: Integer; { Image resolution in dpi. For the obsolete functions, use pixels/cm.}
channels: Integer; { Number of channels in the image. Fingerprint images should always be grayscale, so this value is always 1. }
biometricModality: Integer; { Biometric modality. Always use VRBIO_BIOMETRIC_MODALITY_FINGERPRINT. \ref VrBio_BiometricModality. }
scannerType: Integer; { Scanner type. \ref VrBio_ScannerType. }
imageFormat: Integer; { Formato de imagem: Formato da imagem. \ ref VrBio_ImageFormat. }
bufferSize: Integer; { Size of the buffer }
compressionRate: Integer; { Compression rate. Valid for images that allow compression. \ref VrBio_CompressionRate }
fingerQuality: Integer; { Quality of the fingerprint image. \ref VrBio_FingerQuality }
ISO197944_parameters: PISO197944Parameters; { Only valid if the image if imageFormat is \ref VrBio_ImageFormat::VRBIO_IMAGEFORMAT_ISO19794_4 \ref VrBio_ISO197944Parameters }
buffer: PByte; { Buffer storing the pixels of the image. The position(x,y,c) of a pixel is y*width*channels+x*channels+c. }
reserved: Pointer; { Reserved for future use }
end;
(*
#include "VTypes.h"
#ifdef WIN32
#define DLLIMPORT extern "C" __declspec(dllimport) int __stdcall
#else
#define DLLIMPORT extern "C"
#endif
*)
{ Callback function that receives events..
typedef void (*VrBio_CaptureEventCallback) (
int eventType,
const char* readerName,
VrBio_BiometricImage* image,
const void* userData)
}
TCaptureEventCallback = procedure(eventType: Integer; readerName: PAnsiChar; image: PBiometricImage; userData: Pointer); stdcall;
{ Function responsible for initializing the SDK. This function MUST be called before calling any other method, except \ref VInstallLicense
DLLIMPORT VStartSDK(VrBio_CaptureEventCallback eventCallback);
}
function VStartSDK(eventCallback: TCaptureEventCallback): Integer; stdcall;
{ Function responsible for finalizing the SDK. This function should be called when the SDK is not needed in the application anymore.
DLLIMPORT VStopSDK();
}
function VStopSDK(): Integer; stdcall;
{ Function responsible for starting the capture on a specific fingerprint reader.
After calling this function, the application is able to receive events.
DLLIMPORT VStartReader(const char* readerName);
}
function VStartReader(readerName: PAnsiChar): Integer; stdcall;
Using it looks like this:
implementation
{$R *.dfm}
procedure EventCallback(eventType: Integer; readerName: PAnsiChar; image: PBiometricImage; userData: Pointer); stdcall;
begin
case eventType of
VRBIO_CAPTURE_EVENT_UNPLUG: Form1.Memo1.Lines.Add('Leitor desconectado!');
VRBIO_CAPTURE_EVENT_REMOVED: Form1.Memo1.Lines.Add('Dedo removido!');
VRBIO_CAPTURE_EVENT_PLACED: Form1.Memo1.Lines.Add('Dedo detectado!');
VRBIO_CAPTURE_EVENT_IMAGE_FRAME: Form1.Memo1.Lines.Add('Frame capturado!');
VRBIO_CAPTURE_EVENT_IMAGE_CAPTURED: Form1.Memo1.Lines.Add('Imagem capturada!');
VRBIO_CAPTURE_EVENT_FAKE_FINGER_DETECTED: Form1.Memo1.Lines.Add('Dedo falso detectado!');
VRBIO_CAPTURE_EVENT_FAKE_FINGER_REMOVED: Form1.Memo1.Lines.Add('Dedo falso removido!');
VRBIO_CAPTURE_EVENT_PLUG:
begin
VStartReader(readerName);
Form1.Memo1.Lines.Add('Leitor conectado!');
end;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
VStartSDK(EventCallback);
end;
My questions:
I can use the application and get the Plug, Unplug and Placed events, but when I get the Image Captured event I have an acces vilation.
In the events that are working the EventCallback parameter image is nil. Is the TBiometricImage record conversion correct?
How can I convert the TBiometricImage buffer to a TBitmap and display the captured image in a TImage?
when I get the Image Captured event I have an acces vilation. In the events that are working the EventCallback parameter image is nil. Is the TBiometricImage record conversion correct?
The individual fields are declared fine, but double check that the alignment and padding of your Delphi records match the same alignment and padding used by the structs in C/C++.
Also, more importantly, the VrBio_CaptureEventCallback typedef in C/C++ is declared without any calling convention specified, so it will use the compiler's default convention, which is usually __cdecl instead of __stdcall (can be configured in the compiler settings). In Delphi, you declared TCaptureEventCallback to use stdcall instead of cdecl. You have to make sure you match the calling conventions correctly (the exported DLL functions do use stdcall, so you are OK there).
How can I convert the TBiometricImage buffer to a TBitmap and display the captured image in a TImage?
The SDK documentation does not explain how to process the various image formats. However, just looking at the struct declaration, the buffer field points at the actual image data, and the imageFormat field indicates the format of that data (there is a VrBio_ImageFormat enum that you have not translated yet). So, you would have to look at the imageFormat first to know how to interpret the buffer.
I do see a VConvertImage() function available. So you should be able to convert images to BMP format, if they are not already. Based on the samples in the SDK, it looks like the buffer data might be a standard BMP file format, so you could try copying the buffer to a TMemoryStream and then use the TBitmap.LoadFromStream() method.
There are also GIF and JPG image formats available, which could be handled by TGIFImage and TJPEGImage, respectively, or even TWICImage, if you wanted to display scanned GIF/JPG images without having to convert them to BMP first. There is also a RAW image format available (which apparently your images are using), but there is no standard VCL TGraphic class to handle RAW images, but I think there might be some 3rd party classes floating around if you look around.
Otherwise, you might try converting the image data to BMP, if needed, and then pass the buffer to the Win32 API CreateBitmap/Indirect() or CreateDibSection() function, and then assign the resulting HBITMAP to the TBitmap.Handle property if successful.
Related
There is a directory with jpg files and one jpg file that should be compared with the files in the directory and in this way find 2 graphically identical files. It's about the simplest way. Maybe it is possible to compare the differences in R, G, B (variability), and not the R, G, B values themselves, since they may differ slightly with different degrees of jpeg compression.
for comparing 2 images:
Load the two jpgs into memory located bitmaps
see opening image file on c++ , PNG , JPEG for simple C++ Builder example just port to pascal the class names and usage should be the same in Delphi.
Compute abs differences
use Graphics::TBitmap::ScanLine[y] for fast pixel access, union or BYTE pointed for individual color channel access and compute abs average difference and max abs difference individually for each color channel.
for more info see TBitmap and ScanLine[y] usage and color channel access example
However as SilverWarior pointed out using RGB space is nto good for this so compare in luminance (just convert the RGB to luminance)
Threshold the result
simply if any of max and avg differences is bigger than some threshold the two images are not identical.
To create a list of files either use winapi FindFirst,FindNext,FindClose to obtain the directory list or use the file list from win3.11 VCL components set its directory and obtain the files in form of list...
And then just auto compare the images ...
Here small C++ builder example for comparing 2 images:
//$$---- Form CPP ----
//---------------------------------------------------------------------------
#include <vcl.h>
#include <math.h>
#include <jpeg.hpp>
#pragma hdrstop
#include "win_main.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TMain *Main;
Graphics::TBitmap *bmp0,*bmp1;
//---------------------------------------------------------------------------
int picture_load(Graphics::TBitmap *bmp,AnsiString name)
{
if (bmp==NULL) return 0;
if (!FileExists(name)) return 0;
bmp->HandleType=bmDIB;
bmp->PixelFormat=pf32bit;
AnsiString ext=ExtractFileExt(name).LowerCase();
for(;;)
{
if (ext==".bmp")
{
bmp->LoadFromFile(name);
break;
}
if (ext==".jpg")
{
TJPEGImage *jpg=new TJPEGImage;
if (jpg==NULL) return 0;
jpg->LoadFromFile(name);
bmp->Assign(jpg);
delete jpg;
break;
}
return 0;
}
bmp->HandleType=bmDIB;
bmp->PixelFormat=pf32bit;
return 1;
}
//---------------------------------------------------------------------------
int picture_compare(Graphics::TBitmap *bmp0,Graphics::TBitmap *bmp1)
{
if ((bmp0==NULL)&&(bmp1==NULL)) return 1;
if (bmp0==NULL) return 0;
if (bmp1==NULL) return 0;
if (bmp0->Width !=bmp1->Width ) return 0;
if (bmp0->Height!=bmp1->Height) return 0;
int x,y,a;
double c0,c1,dc,de,maxdif=0.0,avgdif=0.0;
BYTE *p0,*p1;
for (y=0;y<bmp0->Height;y++)
{
p0=(BYTE*)bmp0->ScanLine[y];
p1=(BYTE*)bmp1->ScanLine[y];
for (a=0,x=0;x<bmp0->Width;x++)
{
c0 =p0[a]; c1 =p1[a]; a++; c0*=0.0722; c1*=0.0722; // B
c0+=p0[a]; c1+=p1[a]; a++; c0*=0.7152; c1*=0.7152; // G
c0+=p0[a]; c1+=p1[a]; a++; c0*=0.2126; c1*=0.2126; // R
a++; // A
dc=fabs(c0-c1);if (maxdif<dc) maxdif=dc; avgdif+=dc;
}
}
avgdif/=bmp0->Width;
avgdif/=bmp0->Height;
if (avgdif>10) return 0;
if (maxdif>50) return 0;
return 1;
}
//---------------------------------------------------------------------------
__fastcall TMain::TMain(TComponent* Owner) : TForm(Owner)
{
bmp0=new Graphics::TBitmap;
bmp1=new Graphics::TBitmap;
picture_load(bmp0,"in0.jpg");
picture_load(bmp1,"in1.jpg");
Caption=picture_compare(bmp0,bmp1);
int xs,ys;
xs=bmp0->Width+bmp1->Width;
ys=bmp0->Height;
if (ys<bmp1->Height) ys=bmp1->Height;
ClientWidth=xs;
ClientHeight=ys;
}
//---------------------------------------------------------------------------
void __fastcall TMain::FormDestroy(TObject *Sender)
{
if (bmp0) delete bmp0; bmp0=NULL;
if (bmp1) delete bmp1; bmp1=NULL;
}
//---------------------------------------------------------------------------
void __fastcall TMain::FormPaint(TObject *Sender)
{
Canvas->Draw(0,0,bmp0);
Canvas->Draw(bmp0->Width,0,bmp1);
}
//---------------------------------------------------------------------------
You should play with the thresholds (I chose form very small input sample) to meet your needs and also beware this is comparing as grayscale images so you should add also some color comparison too (integrate some areas into avg color and compare that)
The function picture_compare returns true for "identical" images... beware it expects pf32bit pixelformat for both images !!! different format will change the pixel access and might also change the RGB order which will lead to wrong weights during conversion to luminance/grayscale. The pixelformat is set during picture_load so do not forget to set it if you use different loading method...
Also for comparing the color you might do a histogram for each color channel separately and compare that ...
I used double to prevent (32 bit) integer overflow of avgdif but take in mind for high resolution even double is not safe.
I'm writing a plugin for unity, and I need to send a texture from ios to unity.
There is a UnitySendMessage function which takes char* as a parameter, but I didn't find a way to convert id<MTLTexture> to char*.
How can I send id<MTLTexture> from ios and receive it in unity?
My current code :
//ios side ...
id<MTLTexture> _texture = CVMetalTextureGetTexture(texture);
UnitySendMessage(CALLBACK_OBJECT, CALLBACK_TEXTURE_READY,_texture);//error
//...
//unity side
private void OnTextureReady(string texture_str)
{
IntPtr texture = new IntPtr(Int32.Parse(texture_str));
int width = 256;
int height = 256;
rawImage.texture = Texture2D.CreateExternalTexture(width, height,
TextureFormat.ARGB32, false, false, texture);
}
iOS plugin documentation says that you can only pass strings using UnitySendMessage.
The workaround would be to create a mapping from string to texture objects in Objective-C side, pass the string key via UnitySendMessage and then retrieve the texture object using a custom DllImport function.
Declare you map:
// class field
{
NSMutableDictionary<NSString *, id<MTLTexture>> _textures;
}
// in constructor
_textures = [NSMutableDictionary new];
// in function code
NSString *textureName = #"cookies";
_textures[textureName] = texture; // save MTLTexture for later
UnitySendMessage(CALLBACK_OBJECT, CALLBACK_TEXTURE_READY, textureName);
On the C# side CreateExternalTexture requires a pointer to a texture object of type IntPtr. To obtain it you can declare a DllImport function that takes a texture name and returns IntPtr:
[DllImport("__Internal")]
static extern IntPtr GetMetalTexturePointerByName(string textureName);
and implement it on the iOS side like so:
return plugin->_textures[textureName];
Not sure if it works though in terms of what CreateExternalTexture expects.
See also this post, a guy is doing something similar (but reverse):
Convert uintptr_t to id<MTLTexture>
Delphi syntax:
procedure Move(const Source; var Dest; Count: Integer);
C++ syntax:
extern PACKAGE void __fastcall Move(const void *Source, void *Dest, int Count);
I have used Function Move in Delphi long time ago,
recently I want to call it in C++ Builder 6,
I wrote it as the same as I did in Delphi,
the error appearance --> "Expression Syntax".
Dose anyone know how to call it?
or there is other function works similar to it?
BYTE src[] = "Source Data";
BYTE dst[11];
Move(src, dst, sizeof(dst));
It is better to use memmove in C++:
memmove(dst, src, sizeof(dst));
This is the C++ header for this function. I imported everything already except for that calllback I don't know how to do it.
struct abs_operation;
typedef struct abs_operation ABS_OPERATION; /* forward declaration */
typedef void (BSAPI *ABS_CALLBACK) ( const ABS_OPERATION*, ABS_DWORD, void*);
struct abs_operation {
ABS_CALLBACK Callback; ///< Pointer to application-defined function, implementing operation callback.
} ;
Based on knowledge of your previous questions, it's like this, I think:
type
PABSOperation = ^TABSOperation;
TABSCallback = procedure(const Operation: PABSOperation;
Flags: DWORD; Ptr: Pointer); stdcall;
TABSOperation = record
Callback: TABSCallback;
end;
I am trying to call a function in C from C# though c ++
so basically C# -> C++ - >C
In C#, I have byte[] bytes - which reads the information from the file. I am passing the byte array and the size to C++ .
In C++ I get the byte array and the size but I am not able to convert to the specific data types.
void Image::OpenMemFile(array<Byte>^ data, unsigned int size)
{
Free();
m_dataStream = data;
Byte const* streamData = &data[0]; // this is where it throws error
// Should I use marshaling here ? What call should that ;be ?
hImage = ::OpenMemImage(streamData , size);
modified = false;
}
// this is the function I need to call
EXIVSIMPLE_API HIMAGE OpenMemImage(const BYTE *data, unsigned int size)
{
// code
imgWrap->image = Exiv2::ImageFactory::open(data, size);
}
the C function it needs to call is
Image::AutoPtr ImageFactory::open(const byte* data, long size)
{
/// code
}
I need to help in converting the byte array to const byte* . I realize I need to use Marshaling. Is there a specific function to marshal arrays in C++ ?
Any help is appreciated.
Thanks
pin_ptr<unsigned char> pin_buffer = &data[0];
unsigned char* pData = pin_buffer;