Matlab insertObjectAnnotation labels error

Question

I have this problem each time I try to display a text using insertObjectAnnotation or vision.TextInserter on a video in Matlab 2014b although the functions are defined in this version, does anyone knows what is the problem or how to fix that?

codes I tried %Draw the objects on the frame and label it

blob = vision.BlobAnalysis('BoundingBoxOutputPort', true,...
        'MinimumBlobAreaSource', 'Property', 'MinimumBlobArea', 250);
frame  = step(videoSource);
[bboxes] = step(blob, frame);
labels = 'Object';
frame = insertObjectAnnotation(frame, 'rectangle', bboxes, labels); 

also I tried those examples here

Error using matlab.system.StringSet/checkValues (line 127) The empty string is not a valid StringSet string.

Error in matlab.system.StringSet/setValues (line 113)

Error in matlab.system.StringSet (line 31)

Error in insertObjectAnnotation>getSystemObjects (line 539) textInserter = vision.TextInserter( ...

Error in insertObjectAnnotation (line 109) [textInserter, boxInserter, cache] = getSystemObjects(shape, ...

Error in distance (line 106) frame = insertObjectAnnotation(frame, 'rectangle',bboxes, labels);

Answer 1

By default, the step() method of vision.BlobAnalysis returns 3 outputs: areas, centroids, and the bounding boxes. So, what you have to do is this:

[~, ~, bboxes] = step(blob, frame);