<ol>
<li>Yes. But if you want to export the log and make a chart out of it, you can try this command:</li>
</ol>
<p><code>./darknet detector train data/obj.data cfg/yolov4.cfg yolov4.weights -map | tee results.log</code></p>
<ol start="2">
<li><p>The <strong>blue curve</strong> is the training loss or the error on the training dataset (specifically Complete Intersection-Over-Union or CIoU loss for YOLOv4). For more details on CIoU loss, <a href="https://arxiv.org/abs/1911.08287" rel="noreferrer">check this paper</a>. The <strong>red line</strong> is the mean average precision at 50% Intersection-over-Union threshold (mAP@0.5), which checks if your model it is generalizing well on a <em>never-before-seen dataset</em> or <em>validation set.</em> If you want to understand mAP more, you can refer to this <a href="https://jonathan-hui.medium.com/map-mean-average-precision-for-object-detection-45c121a31173" rel="noreferrer">easy-to-understand blogpost.</a></p>
</li>
<li><p>Are you using a custom dataset? The drop near iteration 1200 might be caused by some problems in your dataset. To check, try these:</p>
<p>(a) Check your dataset - run training with flag <code>-show_imgs</code> i.e. <code>./darknet detector train ... -show_imgs</code> and look at the <code>aug_...jpg</code> images, do you see correct truth bounded boxes?</p>
<p>(b) Check generated files <code>bad.list</code> and <code>bad_label.list</code> if they exist. These files contain the label files that may have problems.</p>
</li>
<li><p>Yes. But if you enable the log file (check my answer - no. 1), then, no.</p>
</li>
</ol>
Loss and mAP chart in YOLOv4
<p>I'm still new to &quot;You Only Look Once&quot; object detection algorithm (YOLOv4 to be exact). I have some questions regarding the mAP and loss chart.</p>
<p>I tried to follow the instructions from <a href="https://github.com/AlexeyAB/darknet#how-to-train-to-detect-your-custom-objects" rel="noreferrer">AlexeyAB Darknet</a>, and train my custom object detector using Google Colabs. After the training, it shows the loss and mAP chart as shown below.</p>
<p>Loss and mAP chart:</p>
<p><a href="https://i.stack.imgur.com/ftGtE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ftGtE.png" alt="image" /></a></p>
<p>My questions are:</p>
<ol>
<li>Is there any chart other than this?</li>
<li>Is this loss for training or validation?</li>
<li>Why is there a sudden drop near iteration 1200?</li>
<li>Is the output of the training only that chart and the weight files?</li>
</ol>