Basic operations of images

Coordinates

Get/set pixels

We can get the value of a pixel through the image.get_pixel(x, y) method.

• image.get_pixel(x, y)
  • For grayscale images: Returns the grayscale value of the (x, y) coordinate.
  • For color images: Returns a tuple of (r, g, b) of the (x, y) coordinate.

Similarly, we can set the value of a pixel through the image.set_pixel(x, y, pixel) method.

• image.set_pixel(x, y, pixel)
  • For grayscale images: Sets the grayscale value of the (x, y) coordinate.
  • For color images: Sets the (r, g, b) value of the (x, y) coordinate.

Example:

img = sensor.snapshot()
img.get_pixel(10,10)
img.set_pixcel(10,10,(255,0,0))#设置坐标(10,10)的像素点为红色(255,0,0)

Get the width and height of an image

• image.width()\ Returns the width of the image (in pixels)

• image.height()\ Returns the height of the image (in pixels)

• image.format()\ Grayscale images will return sensor.GRAYSCALE, and color images will return sensor.RGB565.

• image.size()\ Returns the size of the image (byte)

Image operations

• image.invert()

Inverts, for binary images, 0 (black) becomes 1 (white), and 1 (white) becomes 0 (black).

Note:\ image can be another image object, or an image object read from a (bmp/pgm/ppm) file.\ Both images must be of the same size and type (grayscale/color).

• image.nand(image)\ Performs a NAND operation with another image.

• image.nor(image)\ Performs a NOR operation with another image.

• image.xor(image)\ Performs an XOR operation with another image.

• image.xnor(image)\ Performs an XNOR operation with another image.

• image.difference(image)\ Subtracts another image from this one. For example, for each pixel in each channel, take the absolute value of the difference. This function is often used for motion detection.