Optical under display fingerprint scanners (UDFPS) are used for user authentication. The device screen provides illumination to UDFPS when capturing fingerprints through local high brightness mode (LHBM). However, on device screens that suffer from first frame dimming (FFD), this causes latency in reaching the target luminance required to accurately capture the fingerprint. Further, the latency may vary with the initial image being displayed on the screen or other factors such as ambient light, display brightness setting, etc. when the fingerprint authentication process is initiated. This disclosure describes techniques to dynamically apply different levels of compensation to the screen depending on the initial state of the device to compensate for first frame dimming. In the first technique, the actual luminance in the UDFPS region in the initial state is determined and is used to determine the required compensation. Content-dependent compensation is then applied. In the second technique, an image of known luminance is applied between after initiating authentication and before applying the target LHBM luminance. Due to the introduction of a pre-configured fixed value, overexposure and underexposure are automatically avoided.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.