Height measurement apparatus and height measurement method

A height measurement apparatus comprising:

• a bandpass filter configured to remove light from a measurement object in a wavelength range other than a predetermined wavelength range;
• an optical filter having a transmittance or a reflectance that monotonically changes with wavelength within the predetermined wavelength range, and configured to separate the light from the measurement object by transmission and reflection;
• a first light detector having a plurality of pixels and configured to detect the light from the measurement object via the bandpass filter and the optical filter and output a first detection signal;
• a second light detector having a plurality of pixels and configured to detect the light from the measurement object via the bandpass filter and the optical filter and output a second detection signal;
• a processor configured to calculate wavelength information for each of the plurality of pixels based on the first detection signal and the second detection signal;
• and an analyzer configured to calculate the height of the measurement object based on the wavelength information for each of the plurality of pixels.