Front-end image preprocessing

At a front-end preprocessor of a computing device, the front-end preprocessor disposed electrically between an image sensor and an image signal processor, a method, comprising:

• receiving a first image from the image sensor;
• preprocessing the first image to produce a quantification of content of the first image;
• storing the quantification of the content of the first image;
• receiving a second image from the image sensor;
• preprocessing the second image to produce a quantification of content of the second image;
• comparing the quantification of the content of the second image to the quantification of content of the first image to determine a difference;
• and
• responsive to the difference satisfying a threshold condition, causing a power state of the image signal processor to be changed from a lower power state to a higher power state.

A computing device, comprising:

• an image sensor;
• an image signal processor;
• a front-end preprocessor disposed electrically between the image sensor and the image signal processor;
• a logic subsystem;
• and
• a storage subsystem comprising instructions executable by the logic subsystem to
• receive a first image from the image sensor at the front-end preprocessor;
• convert the first image from a first color space to a second color space;
• preprocess the first image to produce a quantification of content of the first image in the second color space;
• store, at the front-end preprocessor, the quantification of the content of the first image;
• receive a second image from the image sensor at the front-end preprocessor;
• convert the second image from the first color space to the second color space;
• preprocess the second image to produce a quantification of content of the second image in the second color space;
• compare the quantification of the content of the second image to the quantification of content of the first image to determine a difference;
• and
• responsive to the difference satisfying a threshold condition, cause a power state of the image signal processor to be changed from a lower power state to a higher power state.