Error while using foreground detection in matlab with webcam video?

3 次查看（过去 30 天）
Aravind
Aravind 2014-9-17
评论： Aravind 2014-9-18
clear all
% video object to grab frame from live video
vidobj = imaq.VideoDevice('winvideo', 1);
detector = vision.ForegroundDetector(...
'NumTrainingFrames', 50, ... %
'InitialVariance', 30*30); % initial standard deviation of 30
blob = vision.BlobAnalysis(...
'CentroidOutputPort', false, 'AreaOutputPort', false, ...
'BoundingBoxOutputPort', true, ...
'MinimumBlobAreaSource', 'Property', 'MinimumBlobArea', 250);
shapeInserter = vision.ShapeInserter('BorderColor','White');
videoPlayer = vision.VideoPlayer();
for n=1:500
f = step(vidobj);
frame = rgb2gray(f);
fgMask = step(detector, frame);
bbox = step(blob, fgMask);
%out = step(shapeInserter, frame, fgMask); % draw bounding boxes
step(videoPlayer, fgMask); % view results in the video player
end
release(vidobj);
release(videoPlayer);
This is the initial code I've written, I'm trying to display the masked frame, so it should come in black and white where the white ones are the foreground object. But all I get is a completely black output stream. Where have I gone wrong?

请先登录，再回答此问题。

采纳的回答

Dima Lisin
Dima Lisin 2014-9-17
编辑：Dima Lisin 2014-9-17
Hi Aravind,
This is probably because the 'InitialVariance' of the foreground detector is not appropriate for the frame datatype. The value of 30^2 works for 'uint8'. However, the default data type of the frame returned by the step() method of imaq.VideoDevice is 'single'. So you should either do
vidobj = imaq.VideoDevice('winvideo', 1, 'ReturnedDataType', 'uint8');
or set 'InitialVariance' to (30 / 255)^2.

更多回答（0 个）

类别

在 Help Center 和 File Exchange 中查找有关 Computer Vision Toolbox 的更多信息

标签

产品

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by