iOS静态图像捕获使用cvvideoccamera (OpenCV)

Question

我在iOS上使用opencv 2.4.9，需要帮助。

我想在拍摄高分辨率照片时用cvvideoccamera捕捉。我需要摄像机的过程图像方法添加一个成熟的文档捕获通过边缘检测。这工作得很好，但我需要一张识别出的文档的高分辨率照片，一旦文档被检测到。

i found this http://code.opencv.org/svn/gsoc2012/ios/trunk/HelloWorld_iOS/HelloWorld_iOS/VideoCameraController.m

这与照片和视频同时工作，但过程图像方法是不同的，从cvvidecamera委托和我的算法不与这个类工作:-/

但我在OpenCV中搜索cvvideoccamera的相机/摄像机解决方案。

希望得到帮助，对不起我的英语

Answer 1

我将cvVideoCamera类的一些方法添加到cvPhotoCamera类中来解决这个问题。它适用于我，但可能需要一些改进适用于你的代码。

CvPhotoCameraMod.h:

#import <UIKit/UIKit.h>
#import <opencv2/highgui/cap_ios.h>
#import <opencv2/highgui/ios.h>
#define DEGREES_RADIANS(angle) ((angle) / 180.0 * M_PI)
@class CvPhotoCameraMod;
@protocol CvPhotoCameraDelegateMod <CvPhotoCameraDelegate>
- (void)processImage:(cv::Mat&)image;
@end
@interface CvPhotoCameraMod : CvPhotoCamera <AVCaptureVideoDataOutputSampleBufferDelegate>
@property (nonatomic, retain) CALayer *customPreviewLayer;
@property (nonatomic, retain) AVCaptureVideoDataOutput *videoDataOutput;
@property (nonatomic, weak) id <CvPhotoCameraDelegateMod> delegate;
- (void)createCustomVideoPreview;
@end

CvPhotoCameraMod.mm:

#import "CvPhotoCameraMod.h"
#import <CoreGraphics/CoreGraphics.h>
#define DEGREES_RADIANS(angle) ((angle) / 180.0 * M_PI)
@implementation CvPhotoCameraMod

-(void)createCaptureOutput;
{
    [super createCaptureOutput];
    [self createVideoDataOutput];
}
- (void)createCustomVideoPreview;
{
    [self.parentView.layer addSublayer:self.customPreviewLayer];
}

//Method mostly taken from this source: https://github.com/Itseez/opencv/blob/b46719b0931b256ab68d5f833b8fadd83737ddd1/modules/videoio/src/cap_ios_video_camera.mm
-(void)createVideoDataOutput{
    // Make a video data output
    self.videoDataOutput = [AVCaptureVideoDataOutput new];
    //Drop grayscale support here
    self.videoDataOutput.videoSettings  = [NSDictionary dictionaryWithObject:[NSNumber numberWithUnsignedInt:kCVPixelFormatType_32BGRA] forKey:(id)kCVPixelBufferPixelFormatTypeKey];

    // discard if the data output queue is blocked (as we process the still image)
    [self.videoDataOutput setAlwaysDiscardsLateVideoFrames:YES];
    if ( [self.captureSession canAddOutput:self.videoDataOutput] ) {
        [self.captureSession addOutput:self.videoDataOutput];
    }
    [[self.videoDataOutput connectionWithMediaType:AVMediaTypeVideo] setEnabled:YES];
    // set video mirroring for front camera (more intuitive)
    if ([self.videoDataOutput connectionWithMediaType:AVMediaTypeVideo].supportsVideoMirroring) {
        if (self.defaultAVCaptureDevicePosition == AVCaptureDevicePositionFront) {
            [self.videoDataOutput connectionWithMediaType:AVMediaTypeVideo].videoMirrored = YES;
        } else {
            [self.videoDataOutput connectionWithMediaType:AVMediaTypeVideo].videoMirrored = NO;
        }
    }
    // set default video orientation
    if ([self.videoDataOutput connectionWithMediaType:AVMediaTypeVideo].supportsVideoOrientation) {
        [self.videoDataOutput connectionWithMediaType:AVMediaTypeVideo].videoOrientation = self.defaultAVCaptureVideoOrientation;
    }
    // create a custom preview layer
    self.customPreviewLayer = [CALayer layer];
    self.customPreviewLayer.bounds = CGRectMake(0, 0, self.parentView.frame.size.width, self.parentView.frame.size.height);
    self.customPreviewLayer.position = CGPointMake(self.parentView.frame.size.width/2., self.parentView.frame.size.height/2.);
    // create a serial dispatch queue used for the sample buffer delegate as well as when a still image is captured
    // a serial dispatch queue must be used to guarantee that video frames will be delivered in order
    // see the header doc for setSampleBufferDelegate:queue: for more information
    dispatch_queue_t videoDataOutputQueue = dispatch_queue_create("VideoDataOutputQueue", DISPATCH_QUEUE_SERIAL);
    [self.videoDataOutput setSampleBufferDelegate:self queue:videoDataOutputQueue];
}
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
    (void)captureOutput;
    (void)connection;
    if (self.delegate) {
        // convert from Core Media to Core Video
        CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
        CVPixelBufferLockBaseAddress(imageBuffer, 0);
        void* bufferAddress;
        size_t width;
        size_t height;
        size_t bytesPerRow;
        CGColorSpaceRef colorSpace;
        CGContextRef context;
        int format_opencv;
        OSType format = CVPixelBufferGetPixelFormatType(imageBuffer);
        if (format == kCVPixelFormatType_420YpCbCr8BiPlanarFullRange) {
            format_opencv = CV_8UC1;
            bufferAddress = CVPixelBufferGetBaseAddressOfPlane(imageBuffer, 0);
            width = CVPixelBufferGetWidthOfPlane(imageBuffer, 0);
            height = CVPixelBufferGetHeightOfPlane(imageBuffer, 0);
            bytesPerRow = CVPixelBufferGetBytesPerRowOfPlane(imageBuffer, 0);
        } else { // expect kCVPixelFormatType_32BGRA
            format_opencv = CV_8UC4;
            bufferAddress = CVPixelBufferGetBaseAddress(imageBuffer);
            width = CVPixelBufferGetWidth(imageBuffer);
            height = CVPixelBufferGetHeight(imageBuffer);
            bytesPerRow = CVPixelBufferGetBytesPerRow(imageBuffer);
        }
        // delegate image processing to the delegate
        cv::Mat image((int)height, (int)width, format_opencv, bufferAddress, bytesPerRow);
        CGImage* dstImage;
        if ([self.delegate respondsToSelector:@selector(processImage:)]) {
            [self.delegate processImage:image];
        }
        // check if matrix data pointer or dimensions were changed by the delegate
        bool iOSimage = false;
        if (height == (size_t)image.rows && width == (size_t)image.cols && format_opencv == image.type() && bufferAddress == image.data && bytesPerRow == image.step) {
            iOSimage = true;
        }

        // (create color space, create graphics context, render buffer)
        CGBitmapInfo bitmapInfo;
        // basically we decide if it's a grayscale, rgb or rgba image
        if (image.channels() == 1) {
            colorSpace = CGColorSpaceCreateDeviceGray();
            bitmapInfo = kCGImageAlphaNone;
        } else if (image.channels() == 3) {
            colorSpace = CGColorSpaceCreateDeviceRGB();
            bitmapInfo = kCGImageAlphaNone;
            if (iOSimage) {
                bitmapInfo |= kCGBitmapByteOrder32Little;
            } else {
                bitmapInfo |= kCGBitmapByteOrder32Big;
            }
        } else {
            colorSpace = CGColorSpaceCreateDeviceRGB();
            bitmapInfo = kCGImageAlphaPremultipliedFirst;
            if (iOSimage) {
                bitmapInfo |= kCGBitmapByteOrder32Little;
            } else {
                bitmapInfo |= kCGBitmapByteOrder32Big;
            }
        }
        if (iOSimage) {
            context = CGBitmapContextCreate(bufferAddress, width, height, 8, bytesPerRow, colorSpace, bitmapInfo);
            dstImage = CGBitmapContextCreateImage(context);
            CGContextRelease(context);
        } else {
            NSData *data = [NSData dataWithBytes:image.data length:image.elemSize()*image.total()];
            CGDataProviderRef provider = CGDataProviderCreateWithCFData((__bridge CFDataRef)data);
            // Creating CGImage from cv::Mat
            dstImage = CGImageCreate(image.cols,                                 // width
                                     image.rows,                                 // height
                                     8,                                          // bits per component
                                     8 * image.elemSize(),                       // bits per pixel
                                     image.step,                                 // bytesPerRow
                                     colorSpace,                                 // colorspace
                                     bitmapInfo,                                 // bitmap info
                                     provider,                                   // CGDataProviderRef
                                     NULL,                                       // decode
                                     false,                                      // should interpolate
                                     kCGRenderingIntentDefault                   // intent
                                     );
            CGDataProviderRelease(provider);
        }

        // render buffer
        dispatch_sync(dispatch_get_main_queue(), ^{
            self.customPreviewLayer.contents = (__bridge id)dstImage;
        });

        // cleanup
        CGImageRelease(dstImage);
        CGColorSpaceRelease(colorSpace);
        CVPixelBufferUnlockBaseAddress(imageBuffer, 0);
    }
}

@end