#Opencv write text on image how to
#Opencv write text on image code

#Opencv write text on image code

In the example code below, you annotate the image with:Īs you can see again, the drawing functions in OpenCV are so similar and therefore so easy to master.

These angles let us draw just a portion of the arcĮllipse(image, centerCoordinates, axesLength, angle, startAngle, endAngle, color, thickness).

starting and ending angle of the ellipse.

major and minor axis lengths of the ellipse.

Except, instead of a radius, you need to specify the: The syntax for the ellipse() function is quite similar to that for the circle. You can also draw an ellipse on the image, using the ellipse() function in OpenCV. Output image of the puppy with a rectangle drawn over the face. Imshow('Rectangle on Image', rect_image) Draw a rectangle using the rectangle() function Define the starting and end points for the rectangle To study other optional arguments, do visit the OpenCV documentation page here.

Specify its color to be a mixture of blue and green, and its thickness is specified as 3.

Specify the start and end points, to draw a line that is 250-pixels long, horizontally on the image.The y-axis represents the vertical direction or the rows of the image.The x-axis represents the horizontal direction or the columns of the image.Look at the top left corner of the image, you’ll find there the origin of the xy coordinate system. The next two arguments are the starting point and ending point for the line.ĭraw a line from point A(x1, y1) to point B(x2, y2), where A and B represent any two points in the image.Line(image, start_point, end_point, color, thickness) Here’s the syntax for the line() function: In C++, you first create a matrix for the copy of the original image. Before calling the line() function, create a copy of the original image by using:Ī copy will ensure that any changes you make to the image will not affect the original image. In this first example, let’s annotate the image with a color line, using the line() function in OpenCV. To know them in detail, please refer to the OpenCV documentation pages. Each function comes with several optional arguments.

#Opencv write text on image how to

Next, we describe how to annotate images, using the various drawing functions in OpenCV. The top left corner of the image corresponds to the origin of the XY coordinate system having (x=0, y=0). Each line in the code will be discussed in detail so that you understand it fully. Annotate Images With Text Using Different Font Faces and Stylesįirst, take a quick look at this code to annotate an image.Overlay Images With Outlined and Filled Up Half-Ellipses.Input image we are going to use throughout this post. This is the image we will be using in all the example here. We will demonstrate here how to annotate images with geometric shapes and text. That’s because each frame in a video is represented as an image. Once you learn to annotate images, annotating video frames will seem just as easy. Highlighting pixels with different colors for image segmentation.Drawing bounding boxes around objects in case of object detection.Annotating images and videos serves more than one purpose, and OpenCV makes the process straightforward and easy.