## 1 Introduction  
Reducing red blood cells (RBCs) mass in human blood causes anemia. It is the most common blood disease that occurs worldwide. It is responsible for reducing blood's oxygen-carrying capacity, which leads to tissue hypoxia [1]. Changes in morphological and textural features, like the reduction in the size of circulating RBCs or diminishing red color, cause microytic hypochromic anemia (MHA) [2]. Iron deficiency in the human body is the main stimulus of these morphological changes (shape, size, and number of RBCs per unit area) in RBCs. anemia is a global health problem with major consequences related to health, working capacity, and quality of life. According to the World Health Organization (WHO) [3], anemia affects 1.62 billion people, 24.8% of the world's total population, with a financial burden of $3.5 trillion annually worldwide. Changes in the size of RBC elements is the alarming condition for reducing hemoglobin quantity in blood. The normal range of RBC size is 80 to 100 femtolitre/RBC (fl/RBC). RBC's normal diameter and thickness range from 6.2 to 8.2 um and 2 to 2.5 um, respectively [4]. Macrocytosis (size of RBCs greater than normal reference range) and microcytosis (size of RBCs less than normal reference range) defects depend on the size of RBCs. The reference size of RBCs is expressed by an index called mean corpuscular volume (MCV). The normal size of healthy RBCs in terms of MCV is 80 to 100 fl [5]. RBCs with MCV levels below 80 fl cause MHA anemia, while MCV levels above 100 fl cause macroyctic anemia [6]. Anemic patients can be classified into three categories: severe (with hemoglobin <7.0 g/dL), moderate (with hemoglobin <7.0-8.9 g/dL), and mild (with hemoglobin <9.0-10.9 g/dL), based on WHO classification [5]. The hypochromic condition is also initiated due to the varying hemoglobin concentration in the blood. The hypochromic concentration is indicated by mean corpuscular hemoglobin concentration (MCHC). The reduced MCHC causes hypochromatism in single RBCs from the normal range, i.e., MCHC < 32 [7; 8; 9]. Many laboratory tests were carried out for the identification of anemia. Some of the tests are listed in Figure 1.  
The visual representation of normal RBC size is shown in Figure 2a. However, in micro-city hypochromic anemia, RBC size decreases below 80 fl/RBC [2], as shown in Figure 2b. The visual or morphological analysis of peripheral blood smear in the microscopic view is a major measure for diagnosing blood-related diseases like anemia, leukemia, thalassemia, etc. [10; 11]. Most of them become fatal, i.e., anemia, acute lymphoblastic leukemia (ALL), and acute myeloid leukemia (AML), if not treated in time [12]. So far, blood syndrome diagnosis greatly relies upon the hematologist's and pathologist's expertise and excellence. During manual blood cell analysis, a pathologist faces several issues. They require outstanding expertise and rich experience for accurate microscopic blood cell analysis. Figure 1: Clinical tests used for the diagnosis of anemia. Using a simple microscope, pathologists face challenges when identifying or predicting abnormal cell structures. Pathologists also face difficulties defining the percentage change of infected cells from the normal using a compound microscope. Approximately 5-10 min are required for the examination of one slide. In the case of the overlapped structure of RBCs, pathologists cannot accurately differentiate between normal and abnormal shape and size. Manual analysis can be affected due to the fallible nature of humans in terms of fatigue, etc. Current blood analyzers perform CBC counts but do not facilitate the pathologist to examine the blood cell shape and size. The automatic analyzers also show some limitations for abnormal or neoplastic cell detection [13]. According to [14; 15], an automated hematology analyzer cannot recognize abnormal red blood cell shapes and erroneously increase or decrease the results due to interfering factors.