What is imageData in JSON file which comes from labelme tool?

Question

I am trying to convert VIA (VGG Image Annotator) JSON file to Labelme JSON file, but the only problem is imageData attribute in Labelme. I am not able to upload my JSON file into Labelme tool without imageData. Does Anyone has idea how to get imageData or anything which is useful to solve this problem.

Answer 1

You were just not lucky enough to find this in Google :) . The functions can be found in , LabelMe's sources:

def img_b64_to_arr(img_b64):
    f = io.BytesIO()
    f.write(base64.b64decode(img_b64))
    img_arr = np.array(PIL.Image.open(f))
    return img_arr

def img_arr_to_b64(img_arr):
    img_pil = PIL.Image.fromarray(img_arr)
    f = io.BytesIO()
    img_pil.save(f, format='PNG')
    img_bin = f.getvalue()
    if hasattr(base64, 'encodebytes'):
        img_b64 = base64.encodebytes(img_bin)
    else:
        img_b64 = base64.encodestring(img_bin)
    return img_b64

I had problems with theirs if hasattr(base64, 'encodebytes'):..., it generates superfluous \n and b' ', so I rewrote the second one as

import codecs

def encodeImageForJson(image):
    img_pil = PIL.Image.fromarray(image, mode='RGB')
    f = io.BytesIO()
    img_pil.save(f, format='PNG')
    data = f.getvalue()
    encData = codecs.encode(data, 'base64').decode()
    encData = encData.replace('\n', '')
    return encData

Answer 2

First, you shoud install labelme, then try the following:

data = labelme.LabelFile.load_image_file(img_path)
image_data = base64.b64encode(data).decode('utf-8')

Output is the same as JSON file by manual.

Answer 3

It is called base64 type of an image, you can turn image into base64 data by the following code:

import base64
encoded = base64.b64encode(open(img_path, "rb").read())
print(encoded)