Error occurred when converting the image to Array3: ShapeError/IncompatibleShape: incompatible shapes

[AAlieZZ]

Importing Image with image-rs

use std::path::Path;
use image::{io::Reader, imageops};

let img = Reader::open(path)?.decode()?;
let resized_img = imageops::resize(&img, 512, 512, imageops::FilterType::Lanczos3);
let mut data: Vec<u8> = resized_img.into_raw();

Add more images.

for i in 0..255 {
        let img = Reader::open(path)?.decode().unwrap();
        data.extend(img.to_bytes());
}

to Array3

let inp_data: Array3<f32> = Array3::from_shape_vec((256, 512, 512), data)
        .expect("Error converting data to 3D array")
        .map(|x| *x as f32/256.0);

error

thread 'main' panicked at 'Error converting data to 3D array: ShapeError/IncompatibleShape: incompatible shapes'

I don't think I filled in the "shape" parameter incorrectly :(

[Adam Reichold]

What is the length of of data? Are you sure that each pixel is a single byte instead of e.g. four for RGB32?

[AAlieZZ]

What is the length of of data? Are you sure that each pixel is a single byte instead of e.g. four for RGB32?

They're grayscale image, each pixel is typically represented by a single byte of data.

[Adam Reichold]

So what is the length of data just be you call from_shape_vec?

[AAlieZZ]

So what is the length of data just be you call from_shape_vec?

...
for i in 0..255 {
        let img = Reader::open(path)?.decode().unwrap();
        data.extend(img.to_bytes());
}
println!("Data length is {}", data.len());
...

cargo run

Data length is 202375168

[Nil Goyette]

I don't understand how the data length can be 202 375 168. You load a 512x512 image 256 times, and you add it in bytes

256 * 512 * 512 * 4 = 268 435 456

With your number

(202375168 / 512) / 512 = 772
772 / 4 = 193

At least one of your number is wrong

[Adam Reichold]

I'd suggest checking the intermediate images added to the data array, e.g.

...
for i in 0..255 {
        let img = Reader::open(path)?.decode().unwrap();
        let bytes = img.to_bytes();
        assert_eq(bytes.len(), 512 * 512);
        data.extend(bytes);
}
...

Maybe you are just missing a resize operation in the loop?

(If I understand your approach correctly, you would actually expect data to end up with length 256 * 512 * 512 == 67108864 for single-byte-per-pixel gray scale images.)

[AAlieZZ]

I'm also puzzled as to why this number was obtained.

        let img = Reader::open(path)?.decode()?;
        let resized_img = imageops::resize(&img, 512, 512, imageops::FilterType::Lanczos3);
        let data: Vec<u8> = resized_img.into_raw();
        println!("{}", data.len());

The length of the individual image turned out to be 1048576 instead of 512 * 512 == 262144.

[Adam Reichold]

The length of the individual image turned out to be 1048576 instead of 512 * 512 == 262144.

1048576 = 512 * 512 * 4, so

Are you sure that each pixel is a single byte instead of e.g. four for RGB32?

as suggested above.

[AAlieZZ]

Oops! I got confused. Thanks for your help!