Removing any previously draw roi on an image

Hello. I have an image in a UIAxes component (app designer) and have the code below. Everytime I run the code (via pushButton callback), I want tod elete any previous roi ellipses and create a new one, hence I try and delete any previous ones. The way I've done doesn't do anything

            [sx,sy]=size(app.imgArray{1})
            ax=app.UIAxes3;
            g=get(ax,'children')
            findall(g, 'type', 'Ellipse');
            t = findall(g, 'type', 'Ellipse'); delete(t);
            h = images.roi.Ellipse(app.UIAxes3,'Center',[round(sy/2) round(sx/2)],'Semiaxes',[round(sx/2) round(sx/2)],'Color','r','StripeColor','b','LineWidth',1);
            

Have also tried (but didn't work)

            findall(g, 'type', 'line');
            t = findall(g, 'type', 'line'); delete(t);

Answer 1

[Mehmed Saad]

findobj(ax,'Type','images.roi.Ellipse')

[Jason]

Perfect, thankyou