1D Barcode Quick Recognition

## 1D Barcode Quick Recognition

Identifies barcode information within a specified region of an image.

## Module Principle
Typically, a complete barcode consists of quiet zones on both sides, start characters, data characters, and stop characters. This module performs the localization and decoding process for 1D barcodes.

### Algorithm Workflow
1. Locate the region containing the 1D barcode within the image.
2. If the barcode is tilted in the image, rotate it to a horizontal orientation to facilitate decoding.
3. Along the localized horizontal direction, select pixel data from a single row (or an average of multiple rows) for analysis.
4. Scan the row of pixels from left to right, recording the positions of transitions from white to black and black to white (i.e., edge positions).
5. Calculate the distance between adjacent edges, which represents the width of bars or spaces (in pixels).
6. Since the image may be scaled (due to varying distances between the barcode and the camera), the measured width values must be normalized to standard unit module widths.
7. Match the start character from the beginning of the sequence and the stop character from the end of the sequence according to the encoding rules of the specific symbology. If matched successfully, the range of the data area is determined.
8. According to the symbology's encoding rules, each character consists of a fixed number of bar/space units. Group the bar/space sequence by this fixed unit count.
9. Match each group of bar/space units against the symbology's character set to obtain the corresponding digits or characters.
10. Verify the correctness of the decoding using the check digit (if applicable). If verification fails, other rows may be attempted, or decoding may be retried.
11. Output the decoded string, potentially accompanied by the verification result.

## Usage Scenarios
The barcode recognition module is used to locate and identify barcodes within specified regions. It tolerates barcodes rotated at arbitrary angles and those with a certain degree of tilt. This module is commonly applied in scenarios such as logistics code reading, product labeling, and part marking.

### Preceding Modules
The preceding modules for this module are typically camera image acquisition or image preprocessing modules.

## Parameter Configuration Description

### Barcode Type:
*   **Auto:** Automatically infers the barcode type based on the code information.
*   **Codabar:** An early, highly readable numeric barcode.
*   **Code 39:** A highly reliable alphanumeric barcode.
*   **Code 93:** A high-efficiency, high-density alphanumeric barcode.
*   **Code 128:** An extremely high-density, highly reliable, and powerful alphanumeric barcode.
*   **EAN-8:** A product identification code specifically used for retail products with very small packaging areas.
*   **EAN-13:** The most universal and core retail product identification code worldwide.
*   **UPC-A:** A standard barcode for retail products in North America.
*   **UPC-E:** A zero-compressed short version of UPC-A.

### Max Barcodes per ROI:
The maximum number of barcodes to identify within a single detection region.

### Prefix Character Filter:
Filters barcode recognition results to include only those starting with specified characters.

### Character Count Judgment:
Criteria for judging the number of characters in the barcode recognition result.

### Barcode Position Filter:
*   **Ignore:** No position filtering is applied to the recognition results.
*   **Topmost Barcode:** Retains only the barcode located at the topmost position in the results.
*   **Bottommost Barcode:** Retains only the barcode located at the bottommost position in the results.
*   **Leftmost Barcode:** Retains only the barcode located at the leftmost position in the results.
*   **Rightmost Barcode:** Retains only the barcode located at the rightmost position in the results.

### Barcode Check Digit:
*   **None:** No verification is performed on the recognition results.
*   **Enable Verification:** Performs verification on the recognition results.
*   **Verify and Output:** Performs verification on the recognition results and outputs the check digit.

![](/media/202602/读码高级参数_1770100543.png)

### Max Read Attempts:
The maximum number of times to preprocess the image and re-attempt recognition if no barcode result is found.

### Min Scan Lines:
The minimum number of scan lines required for the same barcode during scanning. This parameter is used to filter out potential false barcodes detected in the image.

### Min Line Width:
The minimum width of the narrowest bars and spaces in the barcode, measured in pixels.

### Max Line Width:
The maximum width of the narrowest bars and spaces in the barcode, measured in pixels.

### 1D Barcode Center Filter:
*   **Center X:** Filters recognition results where the horizontal coordinate of the barcode center falls within this range.
*   **Center Y:** Filters recognition results where the vertical coordinate of the barcode center falls within this range.

### Output String on Failure:
The character string to output when no barcode is recognized.

### Display Center Info:
Displays the center coordinates of all recognized barcodes to facilitate viewing for center filtering.

![](/media/202602/条码识别显示设置_1770101971.png)

### Display Settings:
Configures parameters related to ROI, barcode regions, and barcode information display.

![](/media/202602/位置调整_1770106939.png)

### Position Adjustment:
Manually adjusts ROI-related parameters.

### ROI Type:
*   **Rotated Rectangle:** A rectangle that can be moved, resized, and rotated. Its angle can be any value from 0 to 360 degrees.

### ROI Mode:
*   **Single ROI:** Only one barcode recognition detection region.
*   **Array ROI:** Supports multiple barcode recognition regions.

### ROI Source:
*   **Manual ROI:** In this mode, ROI-related parameters can be directly set within this module.
*   **Referenced ROI:** In this mode, ROI-related parameters cannot be modified in this module; they must be imported from an upstream module.

### Position Correction:
*   **Disabled:** No position adjustment is made to the set ROI.
*   **Pose Correction:** Adjusts the position of the set ROI based on the input value.

## Output Description

### Run Result:
Indicates whether the barcode recognition was successful.

### 1D Barcode Count:
The number of barcodes recognized.

### Character Count:
The number of characters in the recognized barcode result.

### Character Output:
The recognized barcode result string.

### 1D Barcode Region Array:
The image regions where the recognized barcodes are located.

### ROI Count:
The number of ROIs.

### ROI Status Array:
Indicates whether a barcode was recognized in each ROI.

## Precautions
1. When using this module, please place the licensed `halcon.dll` and `halconc.dll` files obtained from MVTec into the software release package, then restart the software to enable functionality.
2. This module is only supported on Windows 10 or later operating systems.

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