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readBarcode

Detect and decode 1-D or 2-D barcode in image

Since R2020a

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Syntax

msg = readBarcode(I)
msg = readBarcode(I,roi)
msg = readBarcode(___,format)
[msg,detectedFormat,loc] = readBarcode(___)

Description

msg = readBarcode(I) detects and decodes a 1-D or 2-D barcode in the input image and returns the message associated with that barcode.

If the input image contains multiple barcodes, the readBarcode function decodes only the first barcode detected.

example

msg = readBarcode(I,roi) specifies a rectangular region of interest (ROI) to reduce the area in which the function searches for a barcode. The ROI must be fully contained in the input image.

msg = readBarcode(___,format) specifies barcode formats to reduce the types of barcodes for which the function searches. Specify this argument in addition to any of the input argument combinations in previous syntaxes.

[msg,detectedFormat,loc] = readBarcode(___) additionally returns the format, detectedFormat, and location, loc, of the detected barcode.

Examples

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Open Live Script

Read an image containing a barcode into the workspace.

I = imread("barcode1D.jpg");

Detect the barcode and decode its message.

msg = readBarcode(I);

Display the decoded barcode message. 

disp("Decoded barcode message: " + msg)
Decoded barcode message: 1234567890128
Open Live Script

Read an image containing a barcode into the workspace. 

I = imread("barcode1D.jpg");

Search the image for a 1-D barcode, returning its message, format, and location.

[msg,detectedFormat,loc] = readBarcode(I,'1D');

Display the detected barcode format.

disp("Barcode format: " + detectedFormat)
Barcode format: EAN-13

Annotate the image with the decoded barcode message.

xyBegin = loc(1,:);
Imsg = insertText(I,xyBegin,msg,'BoxOpacity',1,'FontSize',30);

Insert a line to show the scan row. 

imSize = size(Imsg);
Imsg = insertShape(Imsg,'Line',[1 xyBegin(2) imSize(2) xyBegin(2)],'LineWidth',5);

Display the image. 

imshow(Imsg)

Figure contains an axes object. The hidden axes object contains an object of type image.

Open Live Script

Read an image containing a barcode. 

I = imread("barcodeQR.jpg");

Define the ROI in the image that contains the barcode. 

roi = [470, 300, 720, 620];

Search for a QR barcode within the ROI. 

[msg,~,loc] = readBarcode(I,roi,"QR-CODE");

Annotate the image with the decoded message from the detected barcode.

xyText =  loc(2,:);
Imsg = insertText(I,xyText,msg,"BoxOpacity",1,"FontSize",25);

Insert red circles onto the image to indicate the finder pattern locations.

Imsg = insertShape(Imsg, "FilledCircle", [loc, ...
     repmat(10, length(loc), 1)],"ShapeColor","red","Opacity",1);

Display the image. 

imshow(Imsg)

Figure contains an axes object. The hidden axes object contains an object of type image.

Input Arguments

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Input image, specified as a truecolor or grayscale image.

Region of interest, specified as a four-element row vector of the form [x, y, width, height]. The rectangular ROI must be fully contained in the input image. [x,y] specifies the starting point for the ROI relative to the upper-left corner of the image.

If an image contains multiple barcodes, specifying an ROI can help the function detect a particular barcode. For more information, see Read Barcodes In Image.

Barcode format, specified as one of these options. The table lists valid barcode formats.

  • 'all' — Use this option to specify all valid barcode formats. If you do not specify a format, the function uses this option.

  • '1D' — Use this option to specify all valid 1-D barcode formats.

  • '2D' — Use this option to specify all valid 2-D barcode formats.

  • A character vector or string scalar of a valid format — Use this option to specify one barcode format.

  • A cell array of character vectors or vector of strings of valid formats — Use this option to specify multiple barcode formats. The function prioritizes its search for specific barcode formats based on the order of the elements in this array.

Specifying a format can reduce the run time of the function by restricting the barcode search.

1-D Formats2-D Formats
UPC-AQR-CODE
UPC-EDATA-MATRIX
EAN-8AZTEC
EAN-13PDF-417
CODE-39 
CODE-93 
CODE-128 
CODABAR 
ITF 
RSS-14 
RSS-EXPANDED 

Output Arguments

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Barcode message, returned as a string scalar.

Detected barcode format, returned as a string scalar of one of the formats in this table.

1-D Formats2-D Formats
UPC-AQR-CODE
UPC-EDATA-MATRIX
EAN-8AZTEC
EAN-13PDF-417
CODE-39 
CODE-93 
CODE-128 
CODABAR 
ITF 
RSS-14 
RSS-EXPANDED 

Location of barcode, returned as an M-by-2 matrix for 2-D barcodes or a 2-by-2 matrix for 1-D barcodes. The matrix elements represent finder pattern locations.

Barcodeloc ValueFinder Pattern Locations
2-DM-by-2 matrix. M represents the number of [x, y] locations of finder patterns.

1-D2-by-2 matrix of the form [x1, y1;x2, y2], where each row represents the location of a finder pattern.

Tips

  • The function detects only clearly visible barcodes.

  • Specifying a format can reduce the run time of the function by restricting the barcode search.

  • For noisy images with unclear barcodes, use image preprocessing functions, such as imsharpen.

  • The function detects only horizontally or vertically aligned barcodes. Use imrotate to correct poorly aligned barcodes.

Extended Capabilities

Version History

Introduced in R2020a

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See Also

Functions

Topics