CIDetector：CIFaceFeature的边界始终为零

Question

I have no idea why CIFaceFeature I get always returns zero Rectangle:

import Cocoa
import QuartzCore

let url = NSURL(string:"http://cs620522.vk.me/v620522149/12b59/ijvZ6XJWrw0.jpg");
let ciimg:CIImage = CIImage(contentsOfURL:url);
let cid:CIDetector = CIDetector(ofType:CIDetectorTypeFace, context:nil, options:[CIDetectorAccuracy: CIDetectorAccuracyHigh]);
let results:NSArray = cid.featuresInImage(ciimg, options: NSDictionary());
for r in results {
    let face:CIFaceFeature = r as CIFaceFeature;
    NSLog("Face found at (%f,%f) of dimensions %fx%f", face.bounds.origin.x, face.bounds.origin.y, face.bounds.width, face.bounds.height);
}

According to amount of NSLogs it seems CIDetector.featuresInImage works.

Answer 1

You should use println to log the info. Or you can use the following,

NSLog("%@ face", face.bounds.origin.x.description)

Answer 2

A few questions the might inform an answer:

• Is the call to CIImage(contentsOfURL:url) resulting in a valid image? For example, is the resulting image extent a non empty rect?
• Does the image have orientation metadata?