kennethzhangml / boxfinder

BMP Image Edge Detection and Annotation

BoxFinder: BMP Image Edge Detection and Annotation

BoxFinder is a C program designed to detect and annotate rectangular objects in BMP images. It utilizes edge detection to find potential objects and marks them in the image.

Functions

Image* loadBMP(const char* filename)

Loads a BMP image from the specified file.

• Parameters
  • filename: Path to the BMP file.
• Returns
  • A pointer to an Image structure containing the loaded image data.

double colorMagnitudeDiff(unsigned char* pixel1, unsigned char* pixel2)

Calculates the color magnitude difference between two pixels.

• Parameters
  • pixel1: Pointer to the first pixel.
  • pixel2: Pointer to the second pixel.
• Returns
  • The Euclidean distance between the two pixels in color space.

void detectHorizontalEdges(Image* img, int y, double magThresh, int* leftEdge, int* rightEdge)

Detects horizontal edges in a given row of the image.

• Parameters
  • img: Pointer to the image.
  • y: The row in the image to check.
  • magThresh: Threshold for detecting an edge.
  • leftEdge: Pointer to store the left edge position.
  • rightEdge: Pointer to store the right edge position.

void calculateCentroid(int top, int bottom, int left, int right, double* centroidX, double* centroidY)

Calculates the centroid of a box defined by its edges.

• Parameters
  • top, bottom, left, right: Edges of the box.
  • centroidX, centroidY: Pointers to store the centroid coordinates.

void drawRectangle(Image* img, Box box, unsigned char color[3])

Draws a rectangle on the image.

• Parameters
  • img: Pointer to the image.
  • box: The box to draw.
  • color: Color of the rectangle (RGB).

void saveBMP(Image* img, const char* filename)

Saves the image to a BMP file.

• Parameters
  • img: Pointer to the image.
  • filename: Path where the image should be saved.

void detectBoxes(Image* img, double magThresh, int minWidth, int maxWidth, Box* box)

Detects boxes in the image based on edge detection.

• Parameters
  • img: Pointer to the image.
  • magThresh: Threshold for detecting an edge.
  • minWidth, maxWidth: Minimum and maximum width for a potential box.
  • box: Pointer to store the detected box.

Usage

1. Compile the program using a C compiler.
2. Run the program, providing a BMP image file as input.
3. The program will detect and annotate rectangular objects and save the modified image.

Contributing

Contributions are welcome. Please feel free to fork the repository and submit pull requests.

License

This project is open source and available under the MIT License.