Is it possible to add background images in the training set that do not have any classes?

[abhisheksgumadi]

Hi,

Is it possible to add images that are labeled as background (the background node in its annotation xml file) image and annotate the whole image as a bounding box as background in the training set?

I see that after I have trained the SSD to detect a particular kind of object (object v/s background 2 classes) it is throwing a lot of false positives on human faces (that do not contain my object).

So I want SSD to consider human faces as background images. Is it possible to somehow do this?

[abhisheksgumadi]

I was thinking of it is possible to include annotation files for additional background images and not include any

[leosteets]

I was wondering the same thing. Even with a threshold of 0.9 I'm still finding a lot of false positives.

I add some noise to the image in order to preserve the aspect ratio, I found that it increases the precision but it decreases the recall, maybe because I didn't use this technique on training, IDK.

Anyway if it is possible to train the model providing negative samples it would be great. Please let us know if it is possible.

[weiliu89]

Currently, it only samples negatives from images which have ground truth annotation. It is possible to hack the multibox_loss_layer to also select negatives from images which do not have any ground truth (background images).

[abhisheksgumadi]

@weiliu89 can you please suggest what changes in the code is required? That would be of great help. I can make those changes, give it a try and report back my findings. Thanks.

[gurkirt]

Did anybody figured it out?

[YvesSchoenberg]

@weiliu89, could you please give us a pointer to the code where we can add this change? The multibox loss layer did change and #145 does not seem to apply anymore. Thanks.

[weiliu89]

You can search MineHardNegative in the bbox_util.cpp

[abhisheksgumadi]

Hi Wei Liu,

Do you mean MineHardExamples function here? https://github.com/weiliu89/caffe/blob/ssd/src/caffe/util/bbox_util.cpp#L850

Thanks Abhishek S

Thank you!

With Regards, Abhishek S

On Thu, Feb 23, 2017 at 4:50 PM, Wei Liu notifications@github.com wrote:

You can search MineHardNegative in the bbox_util.cpp

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[weiliu89]

Yes.

[guoxiaolu]

Is it possible to add some images with 'background' label, instead purely background image without any label? @weiliu89

[sirluckyluke]

@abhisheksgumadi : i am running in similar problems like you. Did you get your solution running?

[MyVanitar]

Anybody could solve this?