I added a button and check if it works. The result is, I still see the problem.

Well, it takes some time to modify my code. Before do that, please let me ask you the following question; "Is that the standard usage of Biometrics authentication to use a button action after back from background?"

Yes, it is the same.

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Thank you for your response. I understand I need to reload the cell to update its display.

Thank you for your response. The link you described is something related to face tracking. Is it correct link? Sorry for not clear description, but if I use the following, I can get complete color video. var colorSpace = CGColorSpaceCreateDeviceRGB() var bitmapInfo = CGBitmapInfo(rawValue: (CGBitmapInfo.byteOrder32Little.rawValue | CGImageAlphaInfo.premultipliedFirst.rawValue) as UInt32) I just replace those 2 parameters with above-mentioned parameters to get greyscale video. I just wonder if this is correct way to get greyscale video , or I should use other way.