Image capturing apparatus having a function for encoding raw image control method therof, and non-transitory computer-readable storage medium

A control method of an image capturing apparatus having an image capturing unit, a transforming unit configured to transform RAW image data obtained by the image capturing unit into a plurality of channels, and an encoding unit configured to perform a frequency transformation, quantization, and encoding for each channel, the method comprising:

• based on a sub-band of a low-frequency component obtained by the frequency transformation for a channel, in which a luminance component is predominant, obtained by the transforming unit, classifying a luminance of each region in a case where one screen is divided into a plurality of regions;
• computing, for each luminance, an index value representing a degree of difference between data before/after the quantization for each region;
• estimating an image quality based on the index value;
• and
• displaying on a display unit an estimation result in the estimating.

A non-transitory computer-readable storage medium storing a program which causes a computer having an image capturing unit, a transforming unit configured to transform RAW image data obtained by the image capturing unit into a plurality of channels, and an encoding unit configured to perform a frequency transformation, quantization, and encoding for each channel, to execute to

• classify, based on a sub-band of a low-frequency component obtained by the frequency transformation for a channel, in which a luminance component is predominant, obtained by the transforming unit, a luminance of each region in a case where one screen is divided into a plurality of regions;
• compute, for each luminance, an index value representing a degree of difference between data before/after the quantization for each region;
• estimate an image quality based on the index value;
• and
• displaying on a display unit an estimation result in the estimating.

An image capturing apparatus having an image capturing unit, a transforming unit configured to transform RAW image data obtained by the image capturing unit into a plurality of channels, and an encoding unit configured to perform a frequency transformation, quantization, and encoding for each channel, the image capturing apparatus comprising:

• a classifying unit configured to, based on a sub-band of a low-frequency component obtained by the frequency transformation for a channel, in which a luminance component is predominant, obtained by the transforming unit, classify a luminance of each region in a case where one screen is divided into a plurality of regions;
• and
• an estimation unit configured to, for each luminance, compute an index value representing a degree of difference between data before/after the quantization for each region, and estimate an image quality based on the index value,
• wherein the estimation unit estimates an image quality by giving preference to an index value having a lower luminance among the index values for each luminance.

An image capturing apparatus having an image capturing unit, a transforming unit configured to transform RAW image data obtained by the image capturing unit into a plurality of channels, and an encoding unit configured to perform a frequency transformation, quantization, and encoding for each channel, the image capturing apparatus comprising:

• a classifying unit configured to, based on a sub-band of a low-frequency component obtained by the frequency transformation for a channel, in which a luminance component is predominant, obtained by the transforming unit, classify a luminance of each region in a case where one screen is divided into a plurality of regions;
• and
• an estimation unit configured to, for each luminance, compute an index value representing a degree of difference between data before/after the quantization for each region, and estimate an image quality based on the index value,
• wherein the estimation unit derives, as the index value of the luminance, a PSNR value based on the RAW image data obtained by decoding the RAW image data before quantization.