True Random Number Generators (TRNGs) are essential for cryptographic applications. Which can be realized by extracting entropy from quantum systems that are inherently probabilistic. One way to do this is to collect quantum entropy from signals generated by complementary metal-oxide-semiconductor (CMOS) Image Sensors (CISs) while detecting photons emitted through radiative recombination in light-emitting diodes (LEDs). We propose a framework for constructing RNGs based on spontaneous emission and shot noise due to photon absorption using affordable commercial-off-the-shelf (COTS) CISs and LEDs. To verify the entropy of such RNG, we developed a performance analysis methodology based on the second-order correlation function, cross-correlation, and mutual information to study the spatial correlations on the CIS output. Our research simplifies implementing RNGs using COTS components, thereby increasing their adoption and use in various applications. We applied our methodology using COTS components and compared our results against the NIST SP 800-90B entropy estimation suite. Furthermore, we generated truly random numbers through entropy extraction and tested more than 140 GB using Dieharder testing suite, passing all statistical tests.