Image stitching blender image format

Question

I am using OpenCV 3.1 w/ contrib in C++. Trying to recreate the program outlined within the "Learning Image Processing with OpenCV pg 152-161. I copied the code line by line but am getting this resulting error.

//-Create a blender-//S10
    Ptr<Blender> blender = Blender::createDefault(blend_type,false);
    Size dst_sz = resultRoi(corners, sizes).size();
    float blend_width = sqrt(static_cast<float>(dst_sz.area()))* blend_strength / 100.f;
    if(blend_width < 1.f){
        blender = Blender::createDefault(Blender::NO,false);
    }
    else if(blend_type == Blender::MULTI_BAND){
        MultiBandBlender* mb = dynamic_cast<MultiBandBlender*>(blender.get());
        mb->setNumBands(static_cast<int>(ceil(log(blend_width)/log(2.))-1.));
        cout << "Multi-band blender, number of bands: " << mb->numBands() << endl;
    }
    else if(blend_type == Blender::FEATHER){
        FeatherBlender* fb = dynamic_cast<FeatherBlender*>(blender.get());
        fb->setSharpness(1.f/blend_width);
        cout << "Feather blender, sharpness: " << fb->sharpness() << endl;
    }
    blender->prepare(corners,sizes);
    //-Compositing step-//S11
    cout << "Composting..." << endl;
    t = getTickCount();
    Mat img_warped, img_warped_s;
    Mat dilated_mask, seam_mask, mask, mask_warped;
    for(int img_idx = 0; img_idx < num_images; img_idx++){
        cout << "Compositing image #" << indices[img_idx]+1 << endl;

        //-Read image and resize it if necessary-//S11.1
        full_img = imread(img_names[img_idx]);
        if(abs(scale - 1)> 1e-1){
            resize(full_img, img, Size(),scale,scale);
        }
        else{
            img = full_img;
        }
        full_img.release();
        Size img_size = img.size();

        Mat K;
        cameras[img_idx].K().convertTo(K, CV_32F);

        //-Warp the current image-//S11.2
        warper->warp(img,K,cameras[img_idx].R,INTER_LINEAR,BORDER_REFLECT,img_warped);
        //Warp the current image mask
        mask.create(img_size, CV_8U);
        mask.setTo(Scalar::all(255));
        warper->warp(mask,K,cameras[img_idx].R,INTER_NEAREST,BORDER_CONSTANT,mask_warped);

        //-Compenstae exposure error step-//S11.3
        compensator->apply(img_idx,corners[img_idx],img_warped,mask_warped);
        img_warped.convertTo(img_warped, CV_16S);
        img_warped.release();
        img.release();
        mask.release();

        dilate(masks_warped[img_idx], dilated_mask, Mat());
        resize(dilated_mask, seam_mask, mask_warped.size());
        mask_warped = seam_mask & mask_warped;

        //-Blending images step-//S11.4
        blender->feed(img_warped_s,mask_warped,corners[img_idx]);
    }

The issue is occurring on the final line saying:

error: (-215) img.type() == CV_16SC3 || img.type() == CV_8UC3 in function feed

AS the blender::feed function tasks in an img, mask, and tl I assumed the issue was with the img img_warpedvariable and tried converting it to type CV_16SC3 and CV_8UC3 but didn't work. Any help is appreciated.

You never set `img_warped_s` to anything which is causing your issue. — Dmitrii Z., Jul 30 '18 at 20:19
@DmitriiZ. I declared them as Mat's at the beginning of step 11. Do they need to be set to a specific type? — C.Radford, Jul 31 '18 at 14:25
img_warped_s is the rotated image which you feed to the blender. Declaring is not enough, you need to put an image into it. — Dmitrii Z., Jul 31 '18 at 14:27
Your line of code `img_warped.convertTo(img_warped, CV_16S);` should instead be `img_warped.convertTo(img_warped_s , CV_16S);` — Dmitrii Z., Jul 31 '18 at 14:28

score 0 · Accepted Answer · answered Jul 31 '18 at 14:32

0

As stated in the comments I wasn't populating img_warped_s.

answered Jul 31 '18 at 14:32

C.Radford

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Image stitching blender image format

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