Camera-based hemoglobin detection

A method for detecting hemoglobin in a stool sample, the method comprising:

• capturing an image of the stool sample with a camera;
• applying a first bandpass filter to the image at a first wavelength as the image is captured;
• applying a second bandpass filter to the image at a second wavelength as the image is captured;
• applying a third bandpass filter to the image at a third wavelength as the image is captured, wherein the first, second, and third wavelengths are between 450 nm and 690 nm, and wherein the third wavelength is between the first and second wavelengths;
• detecting a spectral signature for the hemoglobin in the stool sample in the image after the first, second, and third bandpass filters are applied to the image, wherein the spectral signature comprises an absorption feature, and wherein detecting the spectral signature comprises:
• performing continuum removal on the spectral signature between 450 nm and 690 nm using linear interpolation to remove a slope from the spectral signature while maintaining the absorption feature, wherein performing the continuum removal comprises:
• determining a first product of a weight and a value of the absorption feature at the first wavelength;
• determining a second product of a complement of the weight and a value of the absorption feature at the second wavelength;
• and
• determining a sum of the first product and the second product;
• and
• determining a band ratio of the absorption feature for each pixel in the image, wherein the band ratio comprises a ratio of the sum and the value of the absorption feature at the third wavelength;
• aggregating the band ratios for the pixels in the image;
• and
• determining that the hemoglobin is present in the stool sample based at least partially upon the aggregation of the band ratios.