1. A method performed by a software process executing on a computer system, the method comprising: obtaining a digital image comprising a plurality of pixels encoded in a YUV color space, each pixel having a luma component of value Y, a blue color-difference component of value U and a red color-difference component of value V; for a specified pixel, calculating whether U is less than a first threshold and V is greater than a second threshold; and determining whether the specified pixel potentially depicts an orange hue depending on a result of the calculation.