JSON_to_txt.py

# -*- coding: utf-8 -*-
"""
Created on Sun May 31 00:44:00 2020

@author: nikhi
"""


import os
import json
from os import listdir, getcwd
from os.path import join

classes = ["person","bicycle","car","motorcycle","airplane","bus","train",
	   "truck","boat","traffic light","fire hydrant","stop sign","parking meter",
	   "bench","bird","cat","dog","horse","sheep","cow","elephant","bear","zebra",
	   "giraffe","backpack","umbrella","handbag","tie","suitcase","frisbee","skis",
	   "snowboard","sports ball","kite","baseball bat","baseball glove","skateboard",
	   "surfboard","tennis racket","bottle","wine glass","cup","fork","knife","spoon",
	   "bowl","banana","apple","sandwich","orange","broccoli","carrot","hot dog","pizza",
	   "donut","cake","chair","couch","potted plant","bed","dining table","toilet","tv",
	   "laptop","mouse","remote","keyboard","cell phone","microwave","oven","toaster","sink",
	   "refrigerator","book","clock","vase","scissors","teddy bear","hair drier","toothbrush"]

#box form[x,y,w,h]
def convert(size,box):
    #dw = 1./size[0]
    #dh = 1./size[1]
    x = box[0]
    y = box[1]
    w = box[2]
    h = box[3]
    return (x,y,w,h)

def convert_annotation():
    with open('G:\My Drive\ML_DL_Stuff\Object Detection\MSCOCO_data\instances_val2017.json','r') as f:
        data = json.load(f)
    for item in data['images']:
        image_id = item['id']      
        file_name = item['file_name']
        width = item['width']
        height = item['height']
        value = filter(lambda item1: item1['image_id'] == image_id,data['annotations'])
        outfile = open('G:\My Drive\ML_DL_Stuff\Object Detection\MSCOCO_data/val2017_yolo_GT_text_files/%s.txt'%(file_name[:-4]), 'a+')
        for item2 in value:
    	    category_id = item2['category_id']
    	    value1 = list(filter(lambda item3: item3['id'] == category_id,data['categories']))
    	    name = value1[0]['name']
    	    class_id = classes.index(name)
    	    box = item2['bbox']
    	    bb = convert((width,height),box)
    	    outfile.write(str(class_id)+" "+" ".join([str(a) for a in bb]) + '\n')
        outfile.close()
			
if __name__ == '__main__':
    convert_annotation()