Incorrect id and image_id after merging

[Dipankar1997161]

Hey,
I was merging 2 json files, one file image_id starts from 600 to 999. second one has image_id from 000 to 399.

After merging the 2 files, the image id for the first file (600 to 999) is generated correctly.
However, for the second file, the image_ids are wrong. for example, for image_id 399, the generated id is 601 and it follows till 900

Becoz of this, the number of samples for me is reduced to 401 which in reality after merging should be at least over 600.

Could you tell me why is this the case?? how can I resolve this?

Note: I did direct installation using pip install coco-assistant for python 3.6

I have added two snippets

Thank you

[tak-sakumoto]

@Dipankar1997161 I tested a tiny case by merging the below two files(a.json, b.json), and I got merged.json.
I think it's similar to your problem because the first file a.json has higher numbers for image IDs, the second file b.json has the lower that, and there is a gap between the end and the start.
In the result merged.json, no samples were lost, although the start of image IDs got higher.
What is the difference from yours? Just for your information.

a.json

{
    "images": [
        {
            "id": 7,
            "file_name": "0007.jpg"
        },
        {
            "id": 8,
            "file_name": "0008.jpg"
        },
        {
            "id": 9,
            "file_name": "0009.jpg"
        }
    ],
    "annotations": [
        {
            "id": 0,
            "image_id": 7,
            "category_id": 1
        },
        {
            "id": 1,
            "image_id": 8,
            "category_id": 0
        },
        {
            "id": 2,
            "image_id": 9,
            "category_id": 0
        }
    ],
    "categories": [
        {
            "id": 0,
            "name": "aaa",
            "supercategory": "A"
        },
        {
            "id": 1,
            "name": "bbb",
            "supercategory": "B"
        }
    ]
}

b.json

{
    "images": [
        {
            "id": 0,
            "file_name": "0000.jpg"
        },
        {
            "id": 1,
            "file_name": "0001.jpg"
        },
        {
            "id": 2,
            "file_name": "0002.jpg"
        }
    ],
    "annotations": [
        {
            "id": 0,
            "image_id": 0,
            "category_id": 1
        },
        {
            "id": 1,
            "image_id": 1,
            "category_id": 0
        },
        {
            "id": 2,
            "image_id": 2,
            "category_id": 0
        }
    ],
    "categories": [
        {
            "id": 0,
            "name": "aaa",
            "supercategory": "A"
        },
        {
            "id": 1,
            "name": "bbb",
            "supercategory": "B"
        }
    ]
}

merged.json

{
    "images": [
        {
            "id": 7,
            "file_name": "0007.jpg"
        },
        {
            "id": 8,
            "file_name": "0008.jpg"
        },
        {
            "id": 9,
            "file_name": "0009.jpg"
        },
        {
            "id": 10,
            "file_name": "0000.jpg"
        },
        {
            "id": 11,
            "file_name": "0001.jpg"
        },
        {
            "id": 12,
            "file_name": "0002.jpg"
        }
    ],
    "annotations": [
        {
            "id": 0,
            "image_id": 7,
            "category_id": 1
        },
        {
            "id": 1,
            "image_id": 8,
            "category_id": 0
        },
        {
            "id": 2,
            "image_id": 9,
            "category_id": 0
        },
        {
            "id": 3,
            "image_id": 10,
            "category_id": 1
        },
        {
            "id": 4,
            "image_id": 11,
            "category_id": 0
        },
        {
            "id": 5,
            "image_id": 12,
            "category_id": 0
        }
    ],
    "info": null,
    "licenses": null,
    "categories": [
        {
            "id": 0,
            "name": "aaa",
            "supercategory": "A"
        },
        {
            "id": 1,
            "name": "bbb",
            "supercategory": "B"
        }
    ]
}

Env

• Python 3.6.8
• coco-assistant 0.3.5