CODEWITHSUNDEEP
iosswiftmachine-learningcoreml
csch0
csch0

Reputation: 573

Convert a VNCoreMLFeatureValueObservation result (3D Double Array) into multiple UIImages

I have a coreml model which after running, returns a VNCoreMLFeatureValueObservation object with 1 "MultiArray : Double 10 x IMG_SIZE x IMG_SIZE array"

How would I transform this into 10 UIImages each with IMG_SIZE x IMG_SIZE dimensions, and their values being a grayscale?

Upvotes: 1

Views: 1234

Answers (1)

csch0
csch0

Reputation: 573

After snooping around a bit I found I had to add these Helper Functions:

https://github.com/hollance/CoreMLHelpers to my Xcode Project. And from a MultiArray Initialization question: https://stackoverflow.com/a/44462908/403403

I then cobbled together this solution:

 let request = VNCoreMLRequest(model: model) { (request, error) in
            guard let results = request.results as? [VNCoreMLFeatureValueObservation] else {
                fatalError("Model failed to process image")
            }

            let obs : VNCoreMLFeatureValueObservation = (results.first)!
            let m: MLMultiArray = obs.featureValue.multiArrayValue!
            var mArrays = [MLMultiArray]()


            for i in 0..<10 {
                let start = i*(IMG_SIZE*IMG_SIZE) 
                guard let tmp : MLMultiArray = try? MLMultiArray(shape:[768,768], dataType:MLMultiArrayDataType.double) else {
                    fatalError("Unexpected runtime error. MLMultiArray")
                }
                for n in 0..<(IMG_SIZE*IMG_SIZE) {
                    tmp[n] = m[start+n]
                }
                mArrays.append(tmp)
            }



            self.imagePred0.image = mArrays[0].image(offset: 0, scale: 255)!
            self.imagePred1.image = mArrays[1].image(offset: 0, scale: 255)!
            self.imagePred2.image = mArrays[2].image(offset: 0, scale: 255)!
            self.imagePred3.image = mArrays[3].image(offset: 0, scale: 255)!
            self.imagePred4.image = mArrays[4].image(offset: 0, scale: 255)!
            self.imagePred5.image = mArrays[5].image(offset: 0, scale: 255)!
            self.imagePred6.image = mArrays[6].image(offset: 0, scale: 255)!
            self.imagePred7.image = mArrays[7].image(offset: 0, scale: 255)!
            self.imagePred8.image = mArrays[8].image(offset: 0, scale: 255)!
            self.imagePred9.image = mArrays[9].image(offset: 0, scale: 255)!



        }

wish there was a cleaner way, but works for now

Upvotes: 2

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