OV7725 support sensor.IOCTL_SET_READOUT_WINDOW

OpenMV Products
1

Hello, everyone! Should ov7725 sensor now can be support the function IOCTL_SET_READOUT_WINDOW ?

2

No the OV7725 doesn’t support any ioctl’s.

3

Does the MT9M114 sensor support this function ?

I tried it but here is what I got :
Image before IOCTL_SET_READOUT_WINDOW :
test2

Image after IOCTL_SET_READOUT_WINDOW :
test1

4

Yes it should be supported. Can you post the script that you ran ?

5

Hi, it does in limited cases. Depending on the window size this will cause all kinds of issues. Unlike other cameras you cannot move the window around as freely as you want.

6

Here is my code :


import sensor, image, time

sensor.reset()                      # Reset and initialize the sensor.
sensor.set_pixformat(sensor.RGB565) # Set pixel format to RGB565 (or GRAYSCALE)
sensor.set_framesize(sensor.QQVGA)   # Set frame size to QVGA (320x240)
sensor.set_auto_gain(False)
sensor.set_auto_whitebal(False)
sensor.ioctl(sensor.IOCTL_SET_READOUT_WINDOW, (0,0,160,120))
print(sensor.ioctl(sensor.IOCTL_GET_READOUT_WINDOW))

sensor.skip_frames(time = 2000)
clock = time.clock()

while(True):
    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.
7

Yes, to be clear. I implemented the code but the method flat out doesn’t actually work. The MT9M114 won’t let you change around the readout window as you please.

8

Thanks for your answer. As I can’t use IOCTL to improve the fps, is there another way to go over the limit of 80 fps ?

9

There’s a way to go above that. The frame rate for the camera is controlled by a frame rate control register. However, there’s quite a few registers that you have to modify to change the FPS. But, it’s not really that hard.

Are you comfortable reading the register programming manual? I can share that.

10

Thanks for your answer and your time. I have never done that but I will try.