Measuring the width and hight for smallest Bounding Boxes of detected objects

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Abdussalam Elhanashi 2020-1-20

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/501084-measuring-the-width-and-hight-for-smallest-bounding-boxes-of-detected-objects

评论： Abdussalam Elhanashi 2020-5-19

Hi guys,

Kindly looking for Measuring the width and highth for the smallest Bounding Boxex of detected object in the following code

load('Detector.mat');
vidReader = VideoReader('vs_002_00.avi');
vidPlayer = vision.DeployableVideoPlayer;
i = 1;
results = struct('Boxes',[],'Scores',[]);
while(hasFrame(vidReader)) 
I = readFrame(vidReader); 
 % PROCESS
    [bboxes, scores, label] = detect(detector,I,'MiniBatchSize', 128);
    
 % Select strongest detection 
% New - Find those bounding boxes that surpassed a threshold
T = 0.5; % Define threshold here
idx = scores >= T;
% Retrieve those scores that surpassed the threshold
s = scores(idx);
% Do the same for the labels as well
lbl = label(idx);
bboxes = bboxes(idx, :); % This logic doesn't change
for ii = 1 : size(bboxes, 1)
    annotation = sprintf('%s: (Confidence = %f)', lbl(ii), s(ii)); % Change    
    I = insertObjectAnnotation(I, 'rectangle', bboxes(ii,:), annotation); % New - Choose the right box
end
boundingBoxArea = prod(boundingBox(3:4));
step(vidPlayer,I);
 i = i+1;
end
 results = struct2table(results);
 release(vidPlayer);

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Guillaume 2020-1-20

Is the variable boundingBox defined somewhere in your code? It's not clear what its relationship is to bboxes.

You haven't actually asked a question, so I'm not exactly sure what you want.

Abdussalam Elhanashi 2020-1-20

Guillaume yes what i mean by bboxes is the boundingBox that are used for object detection in fact there are many objects detected in the video and i want to measure the hight and width for the smallest bboxes of these detected objects in this code

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采纳的回答

Guillaume 2020-1-20

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/501084-measuring-the-width-and-hight-for-smallest-bounding-boxes-of-detected-objects#answer_411068

编辑：Guillaume 2020-1-20

For the area of Bounding Boxes what is the unit used?

pixel squared. If you want to convert to physical unit (e.g.

) you need to know the scale of your images.

You still haven't explained where boundingBox come from. As far as I can tell, your code uses the variable before defining it.

Using the bboxes variable, this is how you would find the bounding with the smallest area:

bboxes = bboxes(idx, :); % This line from your code. Unchanged
bboxesarea = prod(bboxes(:, 3:4), 2);  %calculate the area of all the bounding boxes by multiplying height by width. produces a column vector
[smallestarea, boxindex] = min(bboxarea);  %get index of smallest bounding box (and area if you need it).
%optional: label the bounding box in red
I = insertObjectAnnotation(I, 'rectangle', bboxes(boxindex,:), sprintf('%s: (Confidence = %f), Area (pixel^2) = %d', lbl(boxindex), s(boxindex), smallestarea), 'Color', 'red');

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Guillaume 2020-1-20

bboxesarea contain the area of all the bounding boxes that you've kept.

Abdussalam Elhanashi 2020-1-20

Hi Guillaume

It gives only the last detected bounding box from the video but not history for all bounding boxes detected with pixel squared measurment

I need the whole history of all detected boxes with pixel squared

i attached image captured from Matlab

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更多回答（1 个）

Image Analyst 2020-1-20

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/501084-measuring-the-width-and-hight-for-smallest-bounding-boxes-of-detected-objects#answer_411042

If you want boxes aligned with the image edges, then use regionprops() and ask for 'BoundingBox'.

If you want boxes at any angle, use bwferet().

Or you could use John's program. https://www.mathworks.com/matlabcentral/fileexchange/34767-a-suite-of-minimal-bounding-objects

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Abdussalam Elhanashi 2020-1-20

Hi Image Analyst

Thanks for your reply

Herein the code Iam using

load('Detector.mat');
vidReader = VideoReader('vs_002_00.avi');
vidPlayer = vision.DeployableVideoPlayer;
i = 1;
results = struct('Boxes',[],'Scores',[]);
while(hasFrame(vidReader)) 
I = readFrame(vidReader); 
 % PROCESS
    [bboxes, scores, label] = detect(detector,I,'MiniBatchSize', 128);
    
 % Select strongest detection 
% New - Find those bounding boxes that surpassed a threshold
T = 0.5; % Define threshold here
idx = scores >= T;
% Retrieve those scores that surpassed the threshold
s = scores(idx);
% Do the same for the labels as well
lbl = label(idx);
bboxes = bboxes(idx, :); % This logic doesn't change
for ii = 1 : size(bboxes, 1)
    annotation = sprintf('%s: (Confidence = %f)', lbl(ii), s(ii)); % Change    
    I = insertObjectAnnotation(I, 'rectangle', bboxes(ii,:), annotation); % New - Choose the right box
end
boundingBoxArea = prod(boundingBox(3:4));
step(vidPlayer,I);
 i = i+1;
end
 results = struct2table(results);
 release(vidPlayer);

I am using deep learning for detecting smoke

in fact regardless what is the object is to be detected what i need is to measure the width and hight for the bounding box appeared in the video even in milimeters

Image Analyst 2020-1-23

Like I said, yes. Make sure you understand my last comment though.

Abdussalam Elhanashi 2020-5-19

@ImageAnalyst

I am using yolov2 for object detection and i want to implement the following issue for my code

i want to make a condition in the time when two or more bounding boxes are near each other for instance 6 feet or less , the color of bounding box need to change its color from green to red. And once these bounding boxes of detected objects get away from each other more than 6 feet the color of these bounding boxes change back from red to green color

6 feet from bounding box to another

Herein my code

close all
clc
load('detectorYolo2.mat');
vidReader = VideoReader('vn_045_00.avi');
vidPlayer = vision.DeployableVideoPlayer;
i = 1;
results = struct('Boxes',[],'Scores',[]);
while(hasFrame(vidReader))    
    % GET DATA
    I = readFrame(vidReader);    
     fps = 0;
     avgfps = [];
     tic;
    % PROCESS
    [bboxes, scores,label] = detect(detectorYolo2,I,'Threshold',0.4);
     newt = toc;
% fps
fps = .9*fps + .1*(1/newt);
avgfps = [avgfps, fps]; %#ok<AGROW>
    
    % Select strongest detection 
    T = 0.0; % Define threshold here
idx = scores >= T;
% Retrieve those scores that surpassed the threshold
s = scores(idx);
% Do the same for the labels as well
lbl = label(idx);
bboxes = bboxes(idx, :); % This logic doesn't change
for ii = 1 : size(bboxes, 1)
    annotation = sprintf('%s: (Confidence = %f)', lbl(ii), s(ii)); % Change    
    I = insertObjectAnnotation(I, 'rectangle', bboxes(ii,:), annotation); % New - Choose the right box
    I  = insertText(I , [1, 1],  sprintf('FPS %2.2f', fps));    
end
step(vidPlayer,I);
 i = i+1;
end
 results = struct2table(results);
 release(vidPlayer);