Table of contents
a picture format
The commonly used formats of pictures are as follows:
BMP: Bitmap, a standard format for image processing in Windows system
JPEG: Chinese meaning is Joint Photographic Experts Group, which is a lossy picture compression format, the higher the compression ratio, the better the image quality Lower
PNG: The Chinese meaning is portable network graphics, which is a lossless compression format WebP: a
picture format with lossy and lossless compression provided by Google
TIFF: bitmap format, independent of hardware, with portability
two-color model
Several commonly used color models:
1. RGB: Using the additive color mixing method, the three colors of red, green and blue are mixed and superimposed in proportion to produce a new color. The
values of the three colors are 0~255 (each channel has 256 color values), which can represent about 16.77 million colors;
2. CMY/CMYK
CMY: Use subtractive color mixer, adopt reflective color mode, and display colors through light reflection
CMYK: Add black on the basis of CMY, through The three primary colors plus the four colors of black are mixed to achieve color printing, and CMYK is the commonly used mode for printing.
3. HSI/HSL (hue saturation lightness/hue saturation light intensity), this model can better digitally process colors, where: H represents the color
range that the human eye can perceive, S represents the saturation of the color, and L represents the color bright.
4. HSV/HSB (hue saturation hue/this model can better digitally process colors, where:
H stands for hue, S stands for saturation, V stands for brightness
5, Lab: the color space is very large and can represent the colors in nature For any color, the Lab color model takes the coordinate Lab, where L represents brightness, a is positive for red,
a is negative for green, b is positive for yellow, and b is negative for blue.
6. YUV/YCbCr: through brightness and color difference To describe the color, where
Y represents brightness, U and V represent chroma, and CbCr represents two independent signals of chroma
Three opencv common modules
All opencv modules are stored in the modules folder. Commonly used modules are:
calib3d: camera calibration and 3D vision
core: kernel module, defining basic data structures and basic operations
dnn: deep learning reasoning
feature2d: feature point processing
flann: fast and recent Neighboring algorithm
gapi: image processing acceleration (not a function module of opencv)
highgui: graphical interface
imgcodecs: reading and writing of graphic files
imgproc: image processing
ml: machine learning
objdetect: image target detection
photo: photo processing
stitching: image stitching
video: video Analysis
videoio: video reading and writing
In addition, the opencv extension library is placed in the opencv-contrib code library.