How to Remove Black From Background of Cropped Image

7 次查看（过去 30 天）
Brian Peoples
Brian Peoples 2020-7-9
回答： Image Analyst 2020-7-10
Hello--
This is not important to the analysis of the picture I am doing, but more for a visual aspect. I was wondering if you had an idea on how I could remove the black background from this already cropped image. My image is as follows:
Here's the already cropped image (1st part of subplot):
My code is as follows (thank you image analyst for all the help thus far):
% Demo to mask of hair switch.
% By Image Analyst.
clc; % Clear the command window.
close all; % Close all figures (except those of imtool.)
clearvars;
workspace; % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 16;
fprintf('Beginning to run %s.m ...\n', mfilename);
%-----------------------------------------------------------------------------------------------------------------------------------
% Read in image.
%file = 'C:\Users\bpeoples\Downloads\MATLAB GLOSS MEASUREMENTS\Sample_Image_Folder\Measurements\Blonde_Hair_Diffused\3CROP_trial 3';
file = 'C:\Users\bpeoples\Downloads\MATLAB GLOSS MEASUREMENTS\Sample_Image_Folder\Measurements\Blonde_Hair_Diffused\3CROP_trial 3';
filename = dir(fullfile(file, '*.jpg'));
total_images = numel(filename);
f = fullfile(file, filename(1).name);
rgbImage = imread(f);
[rows, columns, numberOfColorChannels] = size(rgbImage);
% Display the RGB image full size.
subplot(2, 2, 1);
imshow(rgbImage, []);
axis('on', 'image');
caption = sprintf('Original Image : "%s"', filename(1).name);
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
hp = impixelinfo(); % Set up status line to see values when you mouse over the image.
% Set up figure properties:
% Enlarge figure to full screen.
hFig1 = gcf;
hFig1.Units = 'Normalized';
hFig1.WindowState = 'maximized';
% Get rid of tool bar and pulldown menus that are along top of figure.
% set(gcf, 'Toolbar', 'none', 'Menu', 'none');
% Give a name to the title bar.
hFig1.Name = 'Demo by Image Analyst';
% Do color segmentation to get the blue tape.
[BW,maskedRGBImage] = createMask(rgbImage);
mask = ~BW;
% Get rid of blobs smaller than 10,000 pixels.
mask = bwareaopen(mask, 10000);
% Display the binary image.
subplot(2, 2, 2);
imshow(mask, []);
axis('on', 'image');
caption = sprintf(' Mask Image');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
hp = impixelinfo(); % Set up status line to see values when you mouse over the image.
% Get the area and centroid.
labeledImage = bwlabel(mask);
props = regionprops(labeledImage, 'Area', 'Centroid');
allAreas = [props.Area]
xy = vertcat(props.Centroid);
% Find out which one is closest to the middle.
x = xy(:, 1);
middlex = columns/2
distanceFromMiddle = abs(x - middlex)
[minDistance, indexOfMiddle] = min(distanceFromMiddle)
% Keep the middle blob.
hairMask = ismember(labeledImage, indexOfMiddle);
hairMask = imfill(hairMask, 'holes');
%convert masked image to rgb
I4 = cat(3,hairMask,hairMask,hairMask);
I5 = uint8(I4(500:3499,1:4500,3)).*rgbImage(500:3499,1:4500,1:3);
%_________ divide into 3 equal segments
Top = uint8(I4(500:1500,2250:3750,3)).*rgbImage(500:1500,2250:3750,1:3); %might have to change horizontal scale(.,!,)
Middle = uint8(I4(1500:2500,2250:3750,3)).*rgbImage(1500:2500,2250:3750,1:3);
Bottom = uint8(I4(2500:3499,2250:3750,3)).*rgbImage(2500:3499,2250:3750,1:3);
%__________ transform the 3 segments into rectangles
% Top_Rectangle = Top(1:1001,500:1250,1:3);
% Middle_Rectangle = Middle(1:1001,480:1200,1:3);
% Bottom_Rectangle = Bottom(1:650,400:1200,1:3);
%_________
figure(3);
subplot(2,2,1);
imshow(I5, []);
axis('on', 'image');
caption = sprintf('crop');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
subplot(2,2,2);
imshow(Top, []);
axis('on', 'image');
caption = sprintf('Top');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
subplot(2,2,3);
imshow(Bottom, []);
axis('on', 'image');
caption = sprintf('Bottom');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
subplot(2,2,4);
imshow(Middle, []);
axis('on', 'image');
caption = sprintf('Middle');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
%__________
% Display the RGB image full size.
figure(1)
subplot(2, 2, 3);
imshow(hairMask, []);
axis('on', 'image');
caption = sprintf('Hair Mask');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
% Display the RGB image full size.
subplot(2, 2, 4);
imshow(I5, []);
axis('on', 'image');
caption = sprintf('RGB Hair Mask');
title(caption, 'FontSize', fontSize, 'Interpreter', 'None');
drawnow;
%=====================================================================================================
function [BW,maskedRGBImage] = createMask(RGB)
%createMask Threshold RGB image using auto-generated code from colorThresholder app.
% [BW,MASKEDRGBIMAGE] = createMask(RGB) thresholds image RGB using
% auto-generated code from the colorThresholder app. The colorspace and
% range for each channel of the colorspace were set within the app. The
% segmentation mask is returned in BW, and a composite of the mask and
% original RGB images is returned in maskedRGBImage.
% Auto-generated by colorThresholder app on 06-Jul-2020
%------------------------------------------------------
% Convert RGB image to chosen color space
I = rgb2hsv(RGB);
% Define thresholds for channel 1 based on histogram settings
channel1Min = 0.580; %orig .410
channel1Max = 0.670; %orig. .670
% Define thresholds for channel 2 based on histogram settings
channel2Min = 0.000;
channel2Max = 1.000;
% Define thresholds for channel 3 based on histogram settings
channel3Min = 0.000;
channel3Max = 1.000;
% Create mask based on chosen histogram thresholds
sliderBW = (I(:,:,1) >= channel1Min ) & (I(:,:,1) <= channel1Max) & ...
(I(:,:,2) >= channel2Min ) & (I(:,:,2) <= channel2Max) & ...
(I(:,:,3) >= channel3Min ) & (I(:,:,3) <= channel3Max);
BW = sliderBW;
% Initialize output masked image based on input image.
maskedRGBImage = RGB;
% Set background pixels where BW is false to zero.
maskedRGBImage(repmat(~BW,[1 1 3])) = 0;
end

请先登录，再回答此问题。

回答（1 个）

Image Analyst
Image Analyst 2020-7-10
When you get your top, middle, and bottom images, you can crop each by finding the non-black mask.
% Find where at least one pixel in Red, Green, or Blue Channel is not zero.
nonBlackMask = Top(:, :, 1) ~= 0 | Top(:, :, 2) ~= 0 | Top(:, :, 3) ~= 0;
nonBlackMask = bwareafilt(nonBlackMask, 1); % Take largest region only.
% Measure the Bounding Box.
props = regionprops(nonBlackMask, 'BoundingBox');
% Now crop
Top = imcrop(Top, props.BoundingBox);
Do the same for Middle and Bottom.

类别

在 Help Center 和 File Exchange 中查找有关 Image Processing and Computer Vision 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