If you set the camera into RAW Bayer mode you may be able to approach that FPS. The calculation is correct from the data sheet. However, the camera has an exposure time window which slows things down. If you want to go that fast you have to kill the exposure.
Try out the below code with the frame buffer disabled. You'll see the frame rate up at 92 FPS or so. The actual camera FPS is higher however. It's just we are dropping frames due to the next frame coming right after the first one. If you want to capture all frames you have to do everything in C world. In particular, you have to do all your processing during the line interrupt. See sensor.c.
Note that things like USB, etc. cause the processor to miss turning on the frame capture logic in time. You'll need to cut a lot of interrupt sources out of your special code.
Code: Select all
# Sensor Exposure Control
# This example shows off how to cotnrol the camera sensor's
# exposure manually versus letting auto exposure control run.
# What's the difference between gain and exposure control?
# Well, by increasing the exposure time for the image you're getting more
# light on the camera. This gives you the best signal to noise ratio. You
# in general always want to increase the expsoure time... except, when you
# increase the exposure time you decrease the maximum possible frame rate
# and if anything moves in the image it will start to blur more with a
# higher exposure time. Gain control allows you to increase the output per
# pixel using analog and digital multipliers... however, it also amplifies
# noise. So, it's best to let the exposure increase as much as possible
# and then use gain control to make up any remaining ground.
import sensor, image, time
# Change this value to adjust the exposure. Try 10.0/0.1/etc.
EXPOSURE_TIME_SCALE = 1.0
sensor.reset() # Reset and initialize the sensor.
sensor.set_pixformat(sensor.BAYER) # Set pixel format to RGB565 (or GRAYSCALE)
sensor.set_framesize(sensor.QQVGA) # Set frame size to QVGA (320x240)
# Print out the initial exposure time for comparison.
print("Initial exposure == %d" % sensor.get_exposure_us())
sensor.skip_frames(time = 2000) # Wait for settings take effect.
clock = time.clock() # Create a clock object to track the FPS.
# You have to turn automatic gain control and automatic white blance off
# otherwise they will change the image gains to undo any exposure settings
# that you put in place...
# Need to let the above settings get in...
sensor.skip_frames(time = 500)
current_exposure_time_in_microseconds = sensor.get_exposure_us()
print("Current Exposure == %d" % current_exposure_time_in_microseconds)
# Auto exposure control (AEC) is enabled by default. Calling the below function
# disables sensor auto exposure control. The additionally "exposure_us"
# argument then overrides the auto exposure value after AEC is disabled.
exposure_us = 0)
print("New exposure == %d" % sensor.get_exposure_us())
# sensor.get_exposure_us() returns the exact camera sensor exposure time
# in microseconds. However, this may be a different number than what was
# commanded because the sensor code converts the exposure time in microseconds
# to a row/pixel/clock time which doesn't perfectly match with microseconds...
# If you want to turn auto exposure back on do: sensor.set_auto_exposure(True)
# Note that the camera sensor will then change the exposure time as it likes.
# Doing: sensor.set_auto_exposure(False)
# Just disables the exposure value update but does not change the exposure
# value the camera sensor determined was good.
clock.tick() # Update the FPS clock.
img = sensor.snapshot() # Take a picture and return the image.
print(clock.fps()) # Note: OpenMV Cam runs about half as fast when connected
# to the IDE. The FPS should increase once disconnected.