display color image

[LogWell]

How to view color images stored in HDF5?

It is always inconvenient to only view one channel, and there is also a need to adjust the D0/1/2 and FlipY.

[axelboc]

Hi, we do support RGB images as defined by the HDF5 Image and Palette Specification. All you need is to add attribute CLASS="IMAGE" to your dataset and you should automatically see a new RGB tab in H5Web.

For an example, open H5Web's demo application, select /nD_datasets/threeD_rgb, and inspect the metadata.

[LogWell]

Is there a reload button in the current version?

[axelboc]

Closing/reopening the file doesn't work? Maybe try VS Code's Developer: Reload Webviews command?

[LogWell]

It would be more convenient to have a reload button during debugging (>_<

[LogWell]

There is another problem, if I save the encoded image, will it not be displayed?

import h5py
import cv2

path_jpg = ""
path_h5 = path_jpg[:-4] + "_v1.h5"

with h5py.File(path_h5, "w") as h5f:
    with open(path_jpg, 'rb') as fb:
        binary = fb.read()
        data = np.frombuffer(binary, dtype='uint8')
        dset = h5f.create_dataset('image', data=data)
        dset.attrs["CLASS"] = "IMAGE"

with h5py.File(path_h5, "r") as h5f:
    data = h5f['image'][:]
    img_jpg = cv2.imdecode(data, cv2.IMREAD_COLOR)
    print("img_jpg:", img_jpg.shape)
    cv2.imwrite(path_jpg[:-4] + "_v1.jpg", img_jpg)

[LogWell]

Furthermore, how to visualize depth (uint16) images? Only the palette was supported?

In this example, the color component numeric type is an 8 bit unsigned integer. While this is most common and recommended for general use, other component color numeric datatypes, such as a 16 bit unsigned integer , may be used. This type is specified as the type attribute of the palette dataset. (see H5Tget_type(), H5Tset_type())

[axelboc]

Currently, H5Web supports only IMAGE_SUBCLASS="IMAGE_TRUECOLOR" as well as the following features:

• n-dimensional RGB datasets (i.e. image stacks)
• RGB vs BGR
• transposition, dimension selection
• custom axes (label+values) via the NeXus convention (cf. NXdata)

We're happy to consider supporting more of the HDF5 Image and Palette specification, but the spec is quite dense and we don't want to bloat H5Web with features that few people use, so please know that we will require careful justification when considering feature requests. If you're up for it, please open an issue on the main H5Web repository.

---

Regarding adding a button to reload the file, this is not trivial because this VS Code extension is just a wrapper around H5Web. I'm also a bit reluctant to add a button to the UI that is meant for debugging, especially when it's so easy to close a file and re-open it (unless there's an issue with this that I'm not seeing).

That being said, we could add a VS Code command for this, like "H5Web: Reload" — that'd be fairly straightforward.

[axelboc]

There is another problem, if I save the encoded image, will it not be displayed?

Do you mean that you are storing a JPEG image as binary in HDF5? If so, then this is definitely not going to be supported. :wink: