Im having an issue with template matching.

Question

Farshad Bolouri 2020-7-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/564629-im-having-an-issue-with-template-matching

评论： Image Analyst 2020-7-14

Hello,

I am currently using an template matching algorithm to detect quail calls from a spectrogram.

This algorithm was originally written for spectrograms created from a 10 second audio segments. I am trying to use the same algorithm on a spectrogram created from a 25 minute audio segment. I am not getting the correct results. And I am not sure if the algorithm is giving me the problem. I persnoally don't have a good image processing knowledge yet, so I'd be happy if you could help out.

Here's the code:

function [CallA,CallB,CallC,CallD,Calls] = QCallDetection(app)
Calls = cell(1,4);
pos = cell(1,4);
curtime = app.curLoadInterval*app.loadIntervalRate;% this part is basically setting up the correct time for 25 mins
time = curtime:1:(curtime+app.loadIntervalRate);   %changed for Parallel
%% Template Reading
value = app.QuailCallTemplateDropDown.Value;
if isempty(app.template) || strcmp(value,"Real Bird")
    template=mat2gray(double(imread('template_combined_real_bird_2.jpg')));
else
    template = app.template;
end
if strcmp(value,"Real Bird") || strcmp(value,"Import")
    ceil_x = 30;
    MinProm_x = 0.25;
    temp_length_x = 0.5;
else
    ceil_x = 10;
    MinProm_x = 0.5;
    temp_length_x = 2/3;
end
temp_width=size(template,1);
temp_length=size(template,2);
spec_duration = 10;
%figure;imshow(template,[])
%title('Template')
CallA = [];CallB = [];CallC = [];CallD = [];
%% Quail Call Detection
Spectrograms = app.Spectrograms;
parfor i = 1:4
    Ispec= Spectrograms{i};
    if ~isempty(Spectrograms{i})
        spec_len=size(Ispec,2);
        spec_width=size(Ispec,1);
             figure();imshow(Ispec)
        
        band=round((spec_width-temp_width)/3);
        spec_seg_size=ceil(spec_len/ceil_x);
         
        call_candidates=[];
        %call_locations=[];
        no_seg=ceil(spec_len/spec_seg_size)*2-1;
        for s=1:no_seg
            spec_seg=Ispec(band:end-band,(s-1)*ceil(spec_seg_size/2)+1:min((s-1)*ceil(spec_seg_size/2)+1+spec_seg_size,spec_len));
            
            cc=xcorr2(spec_seg,template);
            cc_signal=mat2gray(max(cc));
            cc_signal=cc_signal(round(temp_length/2)-1:end-round(temp_length/2));
            
            TF = islocalmax(cc_signal,'MinProminence',MinProm_x,'ProminenceWindow',temp_length/2);
            locs=find(TF);
            call=(((s-1)*ceil(spec_seg_size/2)+1)+locs)';
            call_candidates=[call_candidates;call];
            
            %         figure;imshow(spec_seg)
            %         x=1:length(cc_signal);
            %         figure;plot(x,cc_signal,x(TF),cc_signal(TF),'r*')
            %         waitforbuttonpress;
        end
        if ~isempty(call_candidates)
            if length(call_candidates)>1
                [L,n]=bwlabel(squareform(pdist(call_candidates))<temp_length*temp_length_x,4);
                for k=1:n
                    [rows,~]=find(L==k);
                    rows=unique(rows);
                    spec_seg=Ispec(band:end-band,max(call_candidates(min(rows))-...
                        round(temp_length/2),1):min(call_candidates(min(rows))+round(temp_length/2),spec_len));
                    
                    cc=xcorr2(spec_seg,template);
                    cc_signal=mat2gray(max(cc));
                    cc_signal=cc_signal(round(temp_length/2)-1:end-round(temp_length/2));
                    
                    TF = islocalmax(cc_signal,'MinProminence',MinProm_x,'ProminenceWindow',temp_length/2);
                    location=find(TF);
                    
                    if call_candidates(min(rows)) <round(temp_length/2)
                        call=(time(1)+(spec_duration/spec_len)*location);
                        Calls{i}=[Calls{i};call'];
                        %call_locations=[call_locations;location'];
                    else
                        call=(time(1)+(spec_duration/spec_len)*(call_candidates(min(rows))+location-round(temp_length/2)));
                        Calls{i}=[Calls{i};call'];
                        %call_locations=[call_locations;call_candidates(min(rows))+location'-round(temp_length/2)];
                    end
                    
                    %                 figure;imshow(spec_seg)
                    %                 x=1:length(cc_signal);
                    %                 figure;plot(x,cc_signal,x(TF),cc_signal(TF),'r*')
                    %                 waitforbuttonpress;
                end
            else
                spec_seg=Ispec(band:end-band,max(call_candidates(1)-round(temp_length/2),1):min(call_candidates(1)+round(temp_length/2),spec_len));
                
                cc=xcorr2(spec_seg,template);
                cc_signal=mat2gray(max(cc));
                cc_signal=cc_signal(round(temp_length/2)-1:end-round(temp_length/2));
                
                
                TF = islocalmax(cc_signal,'MinProminence',MinProm_x,'ProminenceWindow',temp_length/2);
                location=find(TF);
                
                if call_candidates(1) <round(temp_length/2)
                    call=(time(1)+(spec_duration/spec_len)*location)';
                    Calls{i}=[Calls{i};call'];
                    %call_locations=[call_locations;location'];
                else
                    call=(time(1)+(spec_duration/spec_len)*(call_candidates(1)+location-round(temp_length/2)));
                    Calls{i}=[Calls{i};call'];
                    %call_locations=[call_locations;max(call_candidates(1)+location'-round(temp_length/2),1)];
                end
                
                %             figure;imshow(spec_seg)
                %             x=1:length(cc_signal);
                %             figure;plot(x,cc_signal,x(TF),cc_signal(TF),'r*')
                %             waitforbuttonpress;
            end
        end
        
        % For Drawing Bounding Boxes
        %pos{i} = [Calls{i} 1200*ones(length(Calls{i}),1) ...
        %    0.5*ones(length(Calls{i}),1) 1900*ones(length(Calls{i}),1)];
        
    end
end