## Calculate width of each bar of Barcode in Matlab

matlab code for barcode recognition

matlab bar graph labels

side by side bar graph - matlab

I have a barcode and I would like process it in matlab and calculate the width of each bar in a 1-D barcode in pixels.

I have tried converting the image to gray scale through graythresh level and converted it to binary as well.

%read the image code3 barz=imread('barcode1.jpg'); grayBarz=rgb2gray(barz); binImage = imbinarize(barz,graythresh(barz)); s = regionprops(binImage == 0,'Area','PixelIdxList'); imshow(barz);

I want the width in pixels of each bar in the barcode.

Sometime it is fun to be able to do things without needing the full *image processing toolbox*.

The solution below allows you to count the pixel width of every black bar, without needing any additional toolbox:

%% Read the image barz=imread('barcode.jpg'); grayBarz=rgb2gray(barz); %% Extract an horizontal line in the middle sz = size(grayBarz) ; idxMidLine = round(sz(1)/2) ; % index of a line roughly in the middle eline = grayBarz(idxMidLine,:) ; % extract a line eline(eline<128) = 0 ; % sharpen transitions eline = ~logical(eline) ; % convert to logical (0=white / 1=black) %% Now count the pixels npts = numel(eline) ; % number of points in the line % Find every transition: % high to low => -1 % no change => 0 % low to high => +1 idd = find( diff(eline) ) ; % this contain the start and end indices of every interval ddd = [ 1 , idd ; ... idd , npts ] ; % This contains the width of every bar (white and black), % in order from left to right barWidth = diff(ddd) ; if ~eline(1) % The first interval is 0 (is white) pixBarWhite = barWidth( 1:2:end ) ; pixBarBlack = barWidth( 2:2:end ) ; else % The first interval is 1 (is black) pixBarBlack = barWidth( 1:2:end ) ; pixBarWhite = barWidth( 2:2:end ) ; end nBarWhite = numel(pixBarWhite) ; nBarBlack = numel(pixBarBlack) ; %% Display results fprintf('Found a total of %d black pixels along the horizontal,\n',sum(pixBarBlack)) fprintf('spread over %d black bars,\n',nBarBlack) fprintf('Individual bar pixel thickness:\n') for k=1:nBarBlack fprintf('Bar %02d : Thickness: %02d pixels\n',k,pixBarBlack(k)) end

For your image it will return:

Found a total of 599 black pixels along the horizontal, spread over 49 black bars, Individual bar pixel thinchness:, Bar 01 : Thickness: 13 pixels Bar 02 : Thickness: 07 pixels Bar 03 : Thickness: 20 pixels % [edited to keep it short] Bar 47 : Thickness: 20 pixels Bar 48 : Thickness: 07 pixels Bar 49 : Thickness: 13 pixels

Note that the variable `pixBarWhite`

also contain the pixel thickness of all the white intervals between the black bars. It might come handy for later ...

**Width of bar in bar plotting is very high,** I am using following piece of code in my GUI to plot a bar in an axes, the above to compute the width parameter that will create that bar width. Bar width, specified as a fraction of the total space available for each bar. The default of 0.8 means the bar width is 80% of the space from the previous bar to the next bar, with 10% of that space on each side. If the width is 1, then the bars within a group touch one another.

Assuming that you alread have the regionprops of the bars the width can be easily obtained through

'MinFeretProperties'

or

'MinorAxisLength'

If your bars are paralell to the image raster you can also use the smaller dimension of the `'BoundingBox'`

https://de.mathworks.com/help/images/ref/regionprops.html

**barcode reader using image processing - File Exchange,** abhas vyas (view profile) · 1 file; 11 downloads. 3.0. decodes a bar code using thickness variation of lines. 3.0. 2 Ratings. 11 Downloads. Updated 05 Apr 2011. Relative width of individual bars, specified as a scalar value in the range [0,1]. Use this property to control the separation of bars within a group. The default value is 0.8, which means that MATLAB separates the bars slightly. If you set this property to 1, then adjacent bars touch. Example: 0.5

**Barcode detection by webcam. - MATLAB Answers,** My functions are based on a demo of Matlab vision, how could i read and decode vidRes = get(obj, 'VideoResolution'); [Center, Width, Num] = Bar(F);. For today's lab, do the following Download BarCodel.png, BarCode2.png, and BarCodeLookUpTable.m and copy them to your working directory in MATLAB In a new MATLAB script, do the following Use imread to open one of the bar code images - Find the width and height of the image using size - Find the column index of the left edge of the first black bar Starting from the first black bar, save the width (in pixels) of each bar and space to a vector - Divide all the widths found by the first width

**[PDF] Real-Time Barcode Recognition,** input, color conversion, feature calculations, barcode recognition, barcode tries to identify a black bar, if it is not there, then the first bar has zero width. If there Generate a barcode image (BMP file) using GS1-128 symbology specifications (section 5.3)

**Adjust bar width according to the x values,** Hello, I have a probem with my bar plot. I group my data with the histc function (groups not evenly spread) and calculate the x and y average for This Matlab code acquires code 39 barcode image from user, reads the barcode and outputs the result. Every line is commented on the program so that it will be easy for others to understand how it works. A cool feature about this program is it refines the barcode image in case the barcode doesn't look clear in the picture, then it reads the barcode.

**Electrical Engineering in Context: Smart Devices, Robots & ,** A scientific calculator has 50 keys for digits and logarithmic and trigonometric functions In Example 2.21, if a laser spot moves across the bar code at 10 m/s, and the width of the thinnest 2.11 Matlab Projects 2.1 2.2 2.3 Acquire microphone hT= [hT text (hB (i).XData+hB (i).XOffset,hB (i).YData,num2str (hB (i).YData.','%.3f'), The text command does the two groups with the two bars of each group labeled in the one call for each bar group. The x position is that of the data plus the offset and the y position is the data value.

##### Comments

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`barcode1.jpg`

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