ios - 为什么 CIDetector 无法检测到最大的矩形？

Question

CIDetector 无法检测到最大的矩形。左图为原始图像，右图为矩形检测图像。它没有检测到完整的矩形。我该如何解决？

- (CIDetector *)highAccuracyRectangleDetector
{
    static CIDetector *detector = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^
    {
        detector = [CIDetector detectorOfType:CIDetectorTypeRectangle 
 context:nil options:@{CIDetectorAccuracy : CIDetectorAccuracyHigh}];
    });
    return detector;
}

- (CIRectangleFeature *)_biggestRectangleInRectangles:(NSArray 
*)rectangles
{
    if (![rectangles count]) return nil;

    float halfPerimiterValue = 0;

    CIRectangleFeature *biggestRectangle = [rectangles firstObject];

    for (CIRectangleFeature *rect in rectangles)
    {
        CGPoint p1 = rect.topLeft;
        CGPoint p2 = rect.topRight;
        CGFloat width = hypotf(p2.x - p1.x, p2.y - p1.y);

        CGPoint p3 = rect.topLeft;
        CGPoint p4 = rect.bottomLeft;
        CGFloat height = hypotf(p4.x - p3.x, p4.y - p3.y);
        CGFloat currentHalfPerimiterValue = (height)+(width);
        _RectHeight = height;
        _RectWidth = width;
        if (halfPerimiterValue < currentHalfPerimiterValue)
        {

            halfPerimiterValue = currentHalfPerimiterValue;
            biggestRectangle = rect;
            NSLog(@"height    %@", @(height));
            NSLog(@"width    %@", @(width));
        }
    }

    return biggestRectangle;
}

Answer 1

最后我通过添加 CIDetectorAspectRatio: @1.667, CIDetectorMaxFeatureCount: @5 解决了这个问题

- (CIDetector *)highAccuracyRectangleDetector
{
    static CIDetector *detector = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^
    {
            detector = [CIDetector detectorOfType:CIDetectorTypeRectangle context:nil options:@{CIDetectorAccuracy : CIDetectorAccuracyHigh, CIDetectorAspectRatio: @1.667, CIDetectorMaxFeatureCount: @5}];
    });
    return detector;
}