[sugar] [OLPC-GSoC] GSoC Status Report: Vision Processing

Nirav Patel olpc
Mon Jun 30 19:08:00 EDT 2008


Joel,

Thanks for testing it.  The python you were using looks fine.  I can't
say for sure without the hardware, but if it's crashing intermittently
during cam.start(), its very likely to be a driver issue.  Does the
webcam work with xawtv?  You might also check dmesg to see if the
driver is complaining about anything.

Nirav

>
> On 6/30/08, Joel Stanley <joel.stan at gmail.com> wrote:
>> Hello Nirav,
>>
>> On Thu, Jun 26, 2008 at 5:37 PM, Nirav Patel <nrpatel at gmail.com> wrote:
>>> functions to add.  Also, I only have the camera in the XO, vivi, and a
>>> poorly supported USB webcam, so if anyone could test it on other
>>> webcams, that would be great.
>>
>> I've had a play with your work on my laptop - a ThinkPad with a webcam
>> supported by the out-of-kernel uvcvideo driver.  The demos you wrote
>> are cool, and it's fun being able to play with the webcam using just a
>> few lines of python.
>>
>> It works well for the most part - I can use it to give me an image 9
>> out of 10 tries, but occasionally the process locks up, requiring me
>> to kill it (ctrl-c was ineffective).
>>
>> I've been trying to reproduce the lockup today, but can't get it to
>> trigger.  I have been able to get the following to happen every 3 or
>> 4th time:
>>
>> $ python test.py
>> Traceback (most recent call last):
>>   File "test.py", line 10, in <module>
>>     cam.start()
>> EnvironmentError: ioctl(VIDIOC_STREAMON) failure : 12, Cannot allocate
>> memory
>>
>> Occasionally when it succeeds, I will get a yellow tinted image.  Both
>> these errors have only happened in this session of testing; the other
>> night I ran it tens of times with only the lockup error.  I don't
>> think I've changed the version of pygame, I'm running git checkout
>> a109246de6.
>>
>> The python I used to test it is below. I'm new to pygame, and my
>> python knowledge is limited, so please point out any mistakes I'm
>> making.
>>
>> Sorry for the vague bug reports.  I'd be glad to help test any patches.
>>
>> Joel
>>
>> --
>>
>> #!/usr/bin/env python
>>
>> import pygame
>> from time import sleep
>> from pygame import camera
>>
>> pygame.init()
>>
>> cam = camera.Camera("/dev/video0", (640, 480), "RGB")
>> cam.start()
>>
>> frame = cam.get_image()
>>
>> disp = pygame.display.set_mode((640, 480))
>> disp.blit(frame, (0,0))
>> pygame.display.flip()
>>
>> sleep(2)
>>
>



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