Image does not fit the frame buffer

OpenMV Products
1

Hi,
I am using H7 R2, and trying to upload a photo and work on it for debugging purposes. I understand that I should use BMP format but am unable to upload the image properly.
Adding the code and the image i’m using. I have also an sd card inside the module.
I can only upload jpg here but I converted it to bmp using this site:

pool
pool955×515 23.9 KB

This is the code:

# Copy image to framebuffer.
#
# This example shows how to load and copy an image to framebuffer for testing.

import sensor, image, time

# Still need to init sensor
sensor.reset()
# Set sensor settings
sensor.set_contrast(1)
sensor.set_gainceiling(16)

# Set sensor pixel format
sensor.set_framesize(sensor.VGA)
sensor.set_pixformat(sensor.GRAYSCALE)

# Load image
img = image.Image("/pool.bmp", copy_to_fb=True)
img.draw_line((100,100,400,100), color = (255, 0, 0))
# Add a small delay to allow the IDE to read the loaded image.
time.sleep_ms(500)
2

What’s the error? The image is too big, then you need to make it smaller.

3

The error is what’s written in the headline. What’s the maximum size that can be handled? And is there an option to use other file types?
Thanks

4

hi there,

you have already declared the frame to be vga resolution.
this means that maximum size can handle will be 640x480.
You can change sensor.set_framesize(sensor.VGA) to much your creteria or import vga res images.

5

Note that if you ask for a larger image than the camera has RAM for it will just crop the image coming in to keep working.

6

What is the maximum size that can be handled for H7 R2 without it begin cropped?
This is the link to the file i’m using:

I get this error using the file:
OSError: Unexpected value read!

# Copy image to framebuffer.
#
# This example shows how to load and copy an image to framebuffer for testing.

import sensor, image, time

# Still need to init sensor
sensor.reset()
# Set sensor settings
sensor.set_contrast(1)
sensor.set_gainceiling(16)

# Set sensor pixel format
sensor.set_framesize(sensor.VGA)
sensor.set_pixformat(sensor.GRAYSCALE)

# Load image
img = image.Image("/picture.bmp", copy_to_fb=True)
img.draw_line((100,100,400,100), color = (255, 0, 0))
# Add a small delay to allow the IDE to read the loaded image.
time.sleep_ms(500)

Also I am saving the file(~300kB) in a memory card attached to the device(if it matters)

7

Just try a VGA image size and the code will work out the maximum result.

As for the error, what line? Please, forums are a two way street. Posting, it doesn’t work and then not being specific about what is wrong won’t help me help you.

8

Oh, okay, I see, you are not using the sensor API.

I apologize, responding to a lot of forum posts from folks putting minimal effort in.

Yeah, we don’t have the smart controls on loading the image yet. So, this is more failure prone.

I think you should be able to do a grayscale VGA image or QVGA with RGB565. There’s a lite 400KB of space available