openmv/usr/examples/09-Feature-Detection/lines.py
2016-09-12 22:17:20 +02:00

50 lines
1.8 KiB
Python

# Hough Transform Example:
#
# This example demonstrates using the Hough transform to find lines in an image.
import sensor, image, time
kernel_size = 1 # kernel width = (size*2)+1, kernel height = (size*2)+1
kernel = [-1, -1, -1,\
-1, +8, -1,\
-1, -1, -1]
# This is a high pass filter kernel. see here for more kernels:
# http://www.fmwconcepts.com/imagemagick/digital_image_filtering.pdf
thresholds = [(200, 255)] # grayscale thresholds
sensor.reset() # Initialize the camera sensor.
sensor.set_pixformat(sensor.GRAYSCALE) # or sensor.RGB565
sensor.set_framesize(sensor.QQVGA) # or sensor.QVGA (or others)
sensor.skip_frames(30) # Let new settings take affect.
clock = time.clock() # Tracks FPS.
# On the OV7725 sensor, edge detection can be enhanced
# significantly by setting the sharpness/edge registers.
# Note: This will be implemented as a function later.
if (sensor.get_id() == sensor.OV7725):
sensor.__write_reg(0xAC, 0xDF)
sensor.__write_reg(0x8F, 0xFF)
while(True):
clock.tick() # Track elapsed milliseconds between snapshots().
sensor.set_pixformat(sensor.GRAYSCALE)
img = sensor.snapshot() # Take a picture and return the image.
img.morph(kernel_size, kernel)
img.binary(thresholds)
# Erode pixels with less than 2 neighbors using a 3x3 image kernel
img.erode(1, threshold = 2)
img.draw_rectangle((0, 0, 160, 120), color=0x00)
# Find lines.
lines = img.find_lines(threshold=40)
# Switch back to RGB to draw red lines.
sensor.set_pixformat(sensor.RGB565) # or sensor.RGB565
img = sensor.snapshot()
for l in lines:
img.draw_line(l, color=(0xFF, 0x00, 0x00))
print(clock.fps()) # Note: Your OpenMV Cam runs about half as fast while
img = sensor.snapshot() # Take a picture and return the image.