Image acquisition apparatus and electronic apparatus including same, and method of controlling image acquisition apparatus
An image acquisition apparatus includes a multispectral imaging sensor for acquiring images of at least four channels based on a wavelength band of about 10 nm to about 1000 nm and a processor for setting an exposure time for each of the four channels based on transmission efficiency and quantum efficiency for each wavelength of each of the four channels and generating an HDR image using image signals corresponding to the four channels and obtained according to the set exposure time.
1 . An image acquisition apparatus comprising:
a multispectral imaging (MSI) sensor configured to acquire a plurality of image signals corresponding to at least four channels based on a wavelength band of about 10 nm to about 1000 nm; and
a processor configured to:
set an exposure time for each of the at least four channels based on transmission efficiency for each of a plurality of wavelengths of each of the at least four channels and quantum efficiency for each of the plurality of wavelengths of each of the at least four channels, and
generate a high dynamic range (HDR) image based on the plurality of image signals corresponding to the at least four channels, the plurality of image signals being obtained based on the set exposure time,
wherein the exposure time is separately set for each of the at least four channels based on transmission efficiency and the quantum efficiency.
2 . The image acquisition apparatus of claim 1 , wherein the processor is further configured to set a different exposure time for each of the at least four channels based on a value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths.
3 . The image acquisition apparatus of claim 1 ,
wherein each of the at least four channels comprises N×N pixels,
wherein the processor is further configured to set a different exposure time for each of the N×N pixels, and
wherein N is a natural number greater than or equal to 2.
4 . The image acquisition apparatus of claim 3 , wherein the processor is further configured to extract a first image signal, among the plurality of image signals, from a first pixel for which a shortest exposure time is set among the N×N pixels when a brightness of an object is greater than or equal to a first threshold value.
5 . The image acquisition apparatus of claim 3 , wherein the processor is further configured to extract a second image signal, among the plurality of image signals, from a second pixel for which a longest exposure time is set among the N×N pixels when a brightness of an object is less than a first threshold value.
6 . The image acquisition apparatus of claim 1 , wherein a maximum value of the exposure time is set based on a value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths.
7 . The image acquisition apparatus of claim 1 , wherein a value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths is a magnitude of a signal of the MSI sensor, the signal being output per unit time.
8 . The image acquisition apparatus of claim 7 , wherein the processor is further configured to:
set a first exposure time for a first channel in which the value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths of the first channel is equal to or greater than a first threshold value, and
set a second exposure time for a second channel, in which the value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths of the second channel is less than the first threshold value, the second exposure time being longer than the first exposure time.
9 . The image acquisition apparatus of claim 1 , wherein the processor is further configured to:
group channels having similar wavelength bands among the at least four channels, and
set a different exposure time for each of the grouped channels.
10 . The image acquisition apparatus of claim 1 , wherein respective areas of the at least four channels of the MSI sensor are different from each other.
11 . The image acquisition apparatus of claim 1 , wherein the processor is further configured to set a different analog gain value for each of the at least four channels.
12 . An electronic apparatus comprising an image acquisition apparatus of claim 1 .
13 . A method of controlling an image acquisition apparatus a multispectral imaging (MSI) sensor configured to acquire a plurality of image signals corresponding to at least four channels based on a wavelength band of about 10 nm to about 1000 nm, the method comprising:
setting an exposure time for each of the at least four channels based on transmission efficiency for each of a plurality of wavelengths of each of the at least four channels and quantum efficiency for each of the plurality of wavelengths of each of the at least four channels; and
generating a high dynamic range (HDR) image based on the plurality of image signals corresponding to the at least four channels the plurality of image signals being obtained based on the set exposure time,
wherein the exposure time is separately set for each of the at least four channels based on transmission efficiency and the quantum efficiency.
14 . The method of claim 13 , wherein the setting of the exposure time comprises setting a different exposure time for each of the at least four channels based on a value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths.
15 . The method of claim 13 ,
wherein each of the at least four channels includes N×N pixels,
wherein the setting of the exposure time comprises setting an exposure time differently for each of the N×N pixels, and
wherein N is a natural number greater than or equal to 2.
16 . The method of claim 15 , wherein the generating of the HDR further comprises extracting a first image signal, among the plurality of image signals, from a pixel for which a shortest exposure time is set among the N×N pixels if a brightness of an object is greater than or equal to a first threshold value.
17 . The method of claim 15 , wherein the generating of the HDR further comprises extracting a second image signal, among the plurality of image signals, from a pixel for which a longest exposure time is set among the N×N pixels if a brightness of an object is less than a first threshold value.
18 . The method of claim 13 , wherein a maximum value of the exposure time is set based on a value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths.
19 . The method of claim 13 , wherein a value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths is a magnitude of a signal of the MSI sensor, the signal being output per unit time.
20 . The method of claim 19 , wherein the setting of the exposure time comprises:
setting a first exposure time for a first channel, in which, the value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths of the first channel is equal to or greater than a first threshold value; and
setting a second exposure time for a second channel, in which, the value obtained by multiplying the transmission efficiency for each of the plurality of wavelengths and the quantum efficiency for each of the plurality of wavelengths of the second channel is less than the first threshold value, the second exposure time being longer than the first exposure time.