TFLite INT8 docs and warning incorrectly require calibration data #1363

Search before asking

• I searched the RF-DETR issues and found no similar bug report.

#1024 discusses export formats broadly but does not track this problem.

Bug

RF-DETR’s TFLite documentation says INT8 export requires representative calibration images for good accuracy. Export also warns that omitting calibration_data will produce poor quantization accuracy.

RF-DETR does not use calibration for INT8 export. quantization="int8" produces a dynamic-range model with INT8 weights and floating-point activations.

Actual behavior:

model.export(
    format="tflite",
    quantization="int8",
    calibration_data=None,
)

Export succeeds and produces a *_dynamic_range_quant.tflite artifact, but logs:

No calibration_data provided for INT8 quantization. Using random data — this will produce poor quantization accuracy.

That warning is incorrect. _quantize_dynamic_range() sets only:

converter.optimizations = [tf.lite.Optimize.DEFAULT]

It never sets converter.representative_dataset. RF-DETR also never passes output_integer_quantized_tflite to onnx2tf, so calibration data cannot affect the generated INT8 model.

I also checked every currently supported onnx2tf release (2.4.0–2.4.3). None defines the download_test_image_data() function that _patch_validation_download() tries to patch, so supplied calibration_data does not currently reach onnx2tf validation either.

Expected behavior:

• Do not warn when calibration_data is omitted.
• Document "int8" as dynamic-range quantization that needs no calibration data.
• Describe calibration_data and max_images according to their current behavior.
• Keep static/full-integer INT8 unsupported.

Environment

• RF-DETR 1.9.3
• develop at 50f21220
• Python 3.12
• onnx2tf 2.4.3

Minimal Reproducible Example

from rfdetr import RFDETRSmall

model = RFDETRSmall()
model.export(
    format="tflite",
    quantization="int8",
    calibration_data=None,
)

Are you willing to submit a PR?

• Yes, I'd like to help by submitting a PR!