1. iOS 自己實(shí)現(xiàn) 名片識(shí)別 一 功能分析,模塊劃分

2. iOS 自己實(shí)現(xiàn) 名片識(shí)別 二 相機(jī)模塊制作

3. iOS 自己實(shí)現(xiàn) 名片識(shí)別 三 圖片處理

4. iOS 自己實(shí)現(xiàn) 名片識(shí)別 四 圖片轉(zhuǎn)文字以及歸類

timg.png

主題:相機(jī)模塊制作

• 1. 框架的選擇與使用
     1.1 相機(jī)功能 使用 AVFoundation
     1.2 矩形檢測(cè): 由于AVFoundation 里面并沒(méi)有矩形檢 測(cè),CoreImage中有矩形檢測(cè),Vision中也有矩形檢測(cè),但是Vision需要iOS11+才行,最終選中 CoreImage 框架來(lái)實(shí)現(xiàn)矩形檢測(cè)
• 2. 相機(jī)的使用
     2.1 展示到屏幕上
     2.2 實(shí)現(xiàn)代理獲取到視頻數(shù)據(jù)
     2.3 由于矩形的檢測(cè)并不需要每一幀都去檢測(cè),所以我采取10幀檢測(cè)一次的辦法
     2.4 篩選最大矩形
     2.5 展示最大矩形
     2.6 點(diǎn)擊拍照后,將照片與特征傳入Result

效果

效果圖.gif

下面來(lái)看看具體實(shí)現(xiàn)

1. 代理的實(shí)現(xiàn)

- (void)captureOutput:(AVCaptureOutput *)output didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{
    // 實(shí)現(xiàn)10幀檢測(cè)一次
    static long count = 0;
    count ++;
    if (count % 10 != 0 ) {
        return;
    }
    
    //1. 生成CIImage
    CVImageBufferRef imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
    CIImage *ciimg = [CIImage imageWithCVImageBuffer:imageBuffer];
    
    //2. 生成矩形特征數(shù)組
    NSArray *rectFeatures = [self.detector featuresInImage:ciimg];
    
    //3. 找出最大矩形
    CIRectangleFeature *rectFeature = [self biggestRectInRects:rectFeatures];
    
    NSLog(@"%@---%@",NSStringFromCGRect(rectFeature.bounds) ,NSStringFromCGRect(ciimg.extent));
    
    _currentImg = ciimg;
    _currentRectFeature = rectFeature;
    
    //4. 顯示在屏幕上
    [self showRectWithImg:ciimg feature:rectFeature];
}

2.從矩形數(shù)組中獲取最大矩形

- (CIRectangleFeature *)biggestRectInRects:(NSArray *)rects
{
    if (rects.count == 0) {
        return nil;
    }
    if (rects.count == 1) {
        return rects.firstObject;
    }
    
    float halfPerimiterValue = 0;
    CIRectangleFeature *biggestRect = [rects firstObject];
    for (CIRectangleFeature *rect in rects)
    {
        CGPoint p1 = rect.topLeft;
        CGPoint p2 = rect.topRight;
        CGFloat width = hypotf(p1.x - p2.x, p1.y - p2.y);
        
        CGPoint p3 = rect.topLeft;
        CGPoint p4 = rect.bottomLeft;
        CGFloat height = hypotf(p3.x - p4.x, p3.y - p4.y);
        
        CGFloat currentHalfPerimiterValue = height + width;
        
        if (halfPerimiterValue < currentHalfPerimiterValue)
        {
            halfPerimiterValue = currentHalfPerimiterValue;
            biggestRect = rect;
        }
    }
    
    return biggestRect;
}

3.根據(jù)特征,屏幕上畫出矩形

- (void)showRectWithImg:(CIImage *)img feature:(CIRectangleFeature *)rectFeature
{
    //當(dāng)連續(xù)2次沒(méi)有檢測(cè)到矩形的時(shí)候 清楚屏幕上的矩形
    static int rectIsNullCount = 0;
    if (rectFeature == nil) {
        rectIsNullCount++;
        if (rectIsNullCount >= 2) {
            rectIsNullCount = 0;
            [self.rectView drawWithPointsfirst:CGPointZero
                                        second:CGPointZero
                                         thrid:CGPointZero
                                         forth:CGPointZero];
            dispatch_async(dispatch_get_main_queue(), ^{
                [self.rectView setNeedsDisplay];
            });
            return;
        }
        return;
    }
    rectIsNullCount = 0;   //檢測(cè)到矩形,計(jì)數(shù)清零
    
    CGRect previewRect = self.rect;
    CGRect imageRect = img.extent;
    
    CGFloat scaleW = CGRectGetWidth(previewRect) / CGRectGetHeight(imageRect);
    CGFloat scaleH = CGRectGetHeight(previewRect) / CGRectGetWidth(imageRect);
   
    
    // 由于ciimage 與屏幕 是旋轉(zhuǎn)90度的,所有需要進(jìn)行調(diào)校和等比例縮放才能畫出點(diǎn)
    [self.rectView
     drawWithPointsfirst:CGPointMake(rectFeature.topLeft.y * scaleW, rectFeature.topLeft.x * scaleH) second:CGPointMake(rectFeature.topRight.y * scaleW, rectFeature.topRight.x * scaleH) thrid:CGPointMake(rectFeature.bottomRight.y * scaleW, rectFeature.bottomRight.x * scaleH) forth:CGPointMake(rectFeature.bottomLeft.y * scaleW, rectFeature.bottomLeft.x * scaleH)];
    
    dispatch_async(dispatch_get_main_queue(), ^{
        [self.rectView setNeedsDisplay];
    });
}